Textbook of Nutrition & Dietics [Third Edition] 9349057107, 9789349057104

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3rd Edition

Monika Sharma MSc (CHN), MA, BSc Principal Shree Balaji Hospital and College of Nursing Kangra, Himachal Pradesh Director Monika’s Nursing Academy Hamirpur, Himachal Pradesh

CBS Publishers & Distributors Pvt Ltd • New Delhi • Bengaluru • Chennai • Kochi • Kolkata • Lucknow • Mumbai • Hyderabad • Nagpur • Patna • Pune • Vijayawada

Disclaimer Science and technology are constantly changing fields. New research and experience broaden the scope of information and knowledge. The authors have tried their best in giving information available to them while preparing the material for this book. Although, all efforts have been made to ensure optimum accuracy of the material, yet it is quite possible some errors might have been left uncorrected. The publisher, the printer and the authors will not be held responsible for any inadvertent errors, omissions or inaccuracies. eISBN: 978-93-490-5710-4 Copyright © Authors and Publisher Third e Book Edition: 2022

All rights reserved. No part of this eBook may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system without permission, in writing, from the authors and the publisher. Published by Satish Kumar Jain and produced by Varun Jain for CBS Publishers & Distributors Pvt. Ltd. Corporate O ice: 204 FIE, Industrial Area, Patparganj, New Delhi-110092 Ph: +91-11-49344934; Fax: +91-11-49344935; Website: www.cbspd.com; www.eduport-global.com; E-mail: [email protected] Head O ice: CBS PLAZA, 4819/XI Prahlad Street, 24 Ansari Road, Daryaganj, New Delhi-110002, India. Ph: +91-11-23289259, 23266861, 23266867; Fax: 011-23243014; Website: www.cbspd.com; E-mail: [email protected]; [email protected].

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Dedicated to My family members for their unconditional support and constant encouragement throughout the venture .

Preface to the Third Edition Our body is very important to us and we should take utmost care of it. If we take proper care of it, the performance of our body will be at its best. The human body is like a finely-tuned engine. To function properly, it requires the right fuel in the form of right food and right fluids. Nurses require a great deal of training and knowledge regarding nutrition due to the fact that there is a connection between nutrition, diet and health. Knowledge regarding nutrition is even helpful for the wellbeing of the nurses too. Nursing is a challenging career with long working hours. The most obvious reason why nurses should be well versed in nutrition is that it can help them in making their patients to learn more about nutrition and nutrition-related problems. This can be made possible only, when they are themselves well-equipped with the basic concepts of nutrition. To fulfil this motive, this book has been updated and designed to meet the requirements of BSc (Nursing) and post-basic BSc nursing students in the best manner possible. This textbook has been written keeping in mind the revised curriculum framed by the Indian Nursing Council. This textbook has been written in simple language and styled in well-organized and systematized way. It is hoped that the content of this book will be useful for all the nursing students and will meet the requirements of students effectively in accordance with the advancements in the field of nursing. This book not only provides information regarding the basics of nutrients, but also provides information regarding cooking rules and preservation of nutrients, balanced diet and the role of nurses in nutritional programs, food additives, food standards, assessment of nutritional status, etc. This book also covers recent guidelines regarding RDAs, updated Health Policies and Acts. Not even a single topic is missed in this book according to INC syllabus. After reading each chapter, student can assess herself or himself by using questions given at the end of each chapter. I believe that this book will become a standard book for nutrition in nursing. Constructive criticism for the book is always welcome.

Monika Sharma

Preface to the First Edition Rich or poor, wise or foolish we all are having one body to take care of. The body’s performance depends on the intelligent care we give to it. The human body is like a finely-tuned engine. To function properly, it requires the right fuel, the right food and the right fluids. Nurses require a great deal of training and knowledge regarding nutrition due to the fact that there is a connection between nutrition, diet and health. Even knowledge regarding nutrition is helpful for the wellbeing of the nurses too. Nursing is a stressful career with long working hours. The most obvious reason why nurses should be well versed in nutrition is that it can help them to help their patients to learn more about nutrition and nutrition related problems. This can be possible only, when they are themselves knowledgeable regarding basic concept of nutrition. To fulfill this motive, this book has been designed to meet the requirements of BSc nursing and post basic BSc nursing students. This textbook has been written keeping in view the curriculum framed by the nursing council of India. This textbook has been written in simple language and styled in well organized and systematized way. It is hoped that content of this book will be useful for all the nursing students and will meet the requirement of students effectively. This book not only provides nutrients information but also provides information regarding cooking rules and preservation of nutrients, balanced diet and role of nurse in nutritional programs, food additives, food standards, assessment of nutritional status, etc. This book also covers recent guidelines regarding RDAs. Not even a single topic is missed in this book according to INC syllabus. After reading each chapter, student can assess herself or himself by using questions given at the end of each chapter. I believe that this book will become a standard book for nutrition in nursing. Monika Sharma

Acknowledgments “I have planted, Apollo watered; but God gave the increase. So then neither is he that planteth any thing, neither he that watereth; but God that giveth the increase”. —1 Cor. 3:6 Project like this is a massive task, takes time and requires help of many hands to accomplish it successfully. I acknowledge my indebtedness to all of them. First of all I want to owe my deepest gratitude to my husband Mr Vikas, my parents, sister, brother and all those loved ones who prayed throughout, for this project. They inspired me in my difficult time and kept me motivated. A very special thanks to a very young contributor, my son, Hardik, who is five, for giving me time for writing and completing this book, which decreased the amount of time I could have spent with him. I am deeply thankful to Ms Sona (Lecturer) and Mrs Madhu Sharma for giving their contributions at many places during working for this project. I wish to express my appreciation and gratitude to all my colleagues who spared their valuable time and provided their critical reviews, without which this project probably would not have been possible. Above all I thank to the Almighty God because He is our refuge and strength. Last but not the least, I extend my special thanks to Mr Satish Kumar Jain (Chairman) and Mr Varun Jain (Managing Director), M/s CBS Publishers and Distributors Pvt Ltd for their wholehearted support in publication of this book. I have no words to describe the role, efforts, inputs and initiatives undertaken by Mr Bhupesh Aarora [Sr. Vice President – Publishing & Marketing (Health Sciences Division)] for helping and motivating me. I sincerely thank the entire CBS team for bringing out the book with utmost care and attractive presentation. I would like to thank Ms Nitasha Arora (Publishing Head & Content Strategist – PGMEE & Nursing), and Dr Anju Dhir (Product Manager cum Commissioning Editor – Medical) for their editorial support. I would also extend my thanks to Mr Shivendu Bhushan Pandey (Sr. Manager & Team Lead), Mr Manoj K Yadav (Production Manager), Mr Ashutosh Pathak (Sr. Proofreader cum Team Coordinator) and all the production team members for devoting laborious hours in designing and typesetting the book.

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Special Features of the Book

LEARNING OBJECTIVES • Describe the classification, functions, sources and recommended daily allowances (RDA) of carbohydrates • Explain BMR and factors affecting BMR

Learning Objectives enlist what the students will learn after studying the entire chapter.

CHAPTER OUTLINE Every chapter starts with a Chapter Outline to give a brief view of the content covered in the chapter.

Concepts • Terminology of Nutrition • History of Nutrition • Concepts of Nutrition • Importance of Food in Health and Disease • Role of Nutrition in Maintaining Health

KEY TERMS • Acidosis: The accumulation of acid and hydrogen ions or depletion of the alkaline reserve (bicarbonate content) in the blood and body tissues, resulting in a decrease in pH. • Allowances: Something permitted or allowed. • Anthocyanins: Anthocyanins arenatural pigments that occur in plants, fruits and vegetables. They give plants the blue and red colors as seen in blueberries and plums. They belong to a group of plant compounds called flavonoids, and are believed to behave as antioxidants.

Important Key Terms used in the chapters are highlighted in the beginning to make students familiar with the basic terms and concepts.

INTRODUCTION A brief Introduction to the chapter has been added in the beginning to arise the interest of the students.

Carbohydrates are hydrates of carbon. The presence of carbon, hydrogen and oxygen in carbohydrates is in the ratio of 1:2:1. Chemically, carbohydrates are defined as polyhydroxy aldehydes or polyhydroxy ketones or substances that yield compounds on hydration. The general formula is CnH2nOn. The term saccharide is derived from the Latin word “Sacchararum” means the sweet taste of sugars. Carbohydrates are widely distributed in plants in which they are formed from carbon dioxide of the atmosphere by photosynthesis. Carbohydrates are sources of quick and sustained energy for our body.

Textbook of Nutrition and Dietetics for BSc Nursing Students

Supplemented with numerous Figures for easy grasp of the relevant topic.

Fig. 6.1  Dietary sources of minerals

Table 6.1: Vitamins and minerals: A comparison Vitamins

Minerals

Chemical composition

Complicated, organic substances

Simple, inorganic substances

Source

From plants and animals

Found in soil and rock

Vulnerability

Destroyed by cooking with heat or chemical reaction

Not vulnerable to heat, chemical reactions

Nutritional requirement

All vitamins are necessary for the body to function properly

Not all minerals required for nutrition

Numerous Tables are used to supplement the text for easy and quick understanding.

Assess Yourself At the end of every chapter, Assess Yourself section covering Long Answer Qs, Short Answer Qs and Multiple Choice Qs have been added for self-evaluation.

Long Answer Questions 1.

Give classification of carbohydrates. Discuss disaccharides in details.

2.

What do you mean by energy? Write down factors affecting energy requirement.

Short Answer Questions  1.

What are carbohydrates mostly made of?

 2.

What are the seven types of carbohydrates?

Multiple Choice Questions 1.

Simplest form of carbohydrate is:

a. Aldehyde and Ketone groups c. Carboxyl group 2. Major function of carbohydrates is: a. To transport material c. To storage and structural framework

xvi

b. d. b. d.

Carboxyl and Alcohol group Hydrogen and Hydroxyl group Storage For structural framework

NATIONAL NUTRITION POLICY

Important Appendices including High yield topics and facts have been covered to keep yourself abreast of the Important facts.

It is a set of nationwide guidelines that specify how the nutritional needs of the population will be met. National nutrition policy was adopted by Government of India in 1993 under the department of women and child development. It advocated a multisectoral strategy for eradicating malnutrition and achieving optimum nutrition for all. Policy advocates the monitoring of nutrition levels across the country. Also sensitizing government machinery on the needs for good nutrition and prevention of malnutrition.

In the Beginning of Book special section on Nutshell have been given for a quick glance to facts and information related to nutrition and dietetics in one go.

Special Features of the Book

ANNEXURE II

Types of Carbohydrates Concentrated forms of simple and compound sugars are a poor source of energy. They get into the blood too fast and cause an insulin over-reaction.

•

Simple sugars: Monosaccharide—single sugar unit ƒ Glucose: Blood sugar ƒ Fructose: Mostly fruits, berries and honey ƒ Galactose: Does not occur free in nature, it is always bonded to something else.

xvii

Syllabus Nutrition and Dietetics Placement: II Semester

Theory: 3 credits (60 hours)

Course description: The course is designed to assist the students to acquire basic knowledge and understanding of the principles of Nutrition and Dietetics and apply this knowledge in the practice of Nursing. Unit Time (Hrs)

Learning objectives

Content

Teaching learning activities

Assessment methods

I

2 (T) Define nutrition and Introduction to Nutrition • Lecture cum its relationship to Concepts discussion health • Definition of nutrition and health • Charts/slides • Malnutrition—under nutrition and over nutrition • Role of nutrition in maintaining health • Factors affecting food and nutrition Nutrients • Classification • Macro and micronutrients • Organic and inorganic • Energy yielding and non-energy yielding Food • Classification—food groups • Origin

• Essay • Short answers • Very short answer

II

3 (T) • Describe the classification, functions, sources and recommended daily allowances (RDA) of carbohydrates • Explain BMR and factors affecting BMR

Carbohydrates • Composition—starches, sugar and cellulose • Recommended daily allowance (RDA) • Dietary sources • Functions Energy • Unit of energy—Kcal • Basal metabolic rate (BMR) • Factors affecting BMR

• Lecture cum discussion • Charts/slides • Models • Display of food items

• Essay • Short answer • Very short answer

III

3 (T) Describe the classification, functions, sources and RDA of proteins

Proteins • Composition • Eight essential amino acids • Functions • Dietary sources • Protein requirements—RDA

• Lecture cum discussion • Charts/slides • Models • Display of food items

• Essay • Short answer • Very short answer

Contd…

Textbook of Nutrition and Dietetics for BSc Nursing Students

xx

Unit Time (Hrs)

Learning objectives

Content

Teaching learning activities

Assessment methods

• Lecture cum discussion • Charts/slides • Models • Display of food items

• Essay • Short answer • Very short answer

3 (T) Describe the Vitamins classification, • Classification—fat soluble and water functions, sources soluble and RDA of vitamins • Fat soluble—vitamins A, D, E, and K • Water soluble—thiamine (vitamin B1), riboflavin (vitamin B2), nicotinic acid, pyridoxine (vitamin B6), pantothenic acid, folic acid, vitamin B12, ascorbic acid (vitamin C) • Functions, dietary sources and requirements—RDA of every vitamin

• Lecture cum discussion • Charts/slides • Models • Display of food items

• Essay • Short answer • Very short answer

VI

3 (T) Describe the Minerals classification, • Classification—major minerals functions, sources (calcium, phosphorus, sodium, and RDA of minerals potassium and magnesium) and trace elements • Functions • Dietary sources • Requirements—RDA

• Lecture cum discussion • Charts/slides • Models • Display of food items

• Short answer • Very short answer

VII

7 (T) Describe and plan 8 (L) balanced diet for different age groups, pregnancy, and lactation

Balanced Diet • Lecture cum • Definition, principles, steps discussion • Food guides—basic four food • Meal planning groups • Lab session on: • RDA—definition, limitations, uses ƒ Preparation • Food exchange system of balanced • Calculation of nutritive value of foods diet for • Dietary fiber different Nutrition Across Life Cycle categories • Meal planning/menu planning— ƒ Low cost definition, principles, steps nutritious • Infant and young child feeding dishes (IYCF) guidelines—breastfeeding, infant foods • Diet plan for different age groups— children, adolescents and elderly • Diet in pregnancy—nutritional requirements and balanced diet plan

• Short answer • Very short answer

IV

2 (T) Describe the classification, functions, sources and RDA of fats

V

Fats • Classification—saturated and unsaturated • Calorie value • Functions • Dietary sources of fats and fatty acids • Fat requirements—RDA

Contd…

Learning objectives

Content

Teaching learning activities

Assessment methods

• Anemia in pregnancy—diagnosis, diet for anemic pregnant women, iron and folic acid supplementation and counseling • Nutrition in lactation—nutritional requirements, diet for lactating mothers, complementary feeding/ weaning VIII

6 (T) Classify and describe Nutritional Deficiency Disorders the common • Protein energy malnutrition— nutritional deficiency magnitude of the problem, causes, disorders and classification, signs and symptoms, identify nurses‘ severe acute malnutrition (SAM), role in assessment, management and prevention and management and nurses‘ role prevention • Childhood obesity—signs and symptoms, assessment, management and prevention and nurses‘ role • Vitamin deficiency disorders— vitamin A, B, C and D deficiency disorders—causes, signs and symptoms, management and prevention and nurses‘ role • Mineral deficiency diseases—iron, iodine and calcium deficiencies— causes, signs and symptoms, management and prevention and nurses‘ role

• Lecture cum discussion • Charts/slides • Models

• Essay • Short answer • Very short answer

IX

4 (T) Principles of diets in 7 (L) various diseases

Therapeutic Diets • Definition, objectives, principles • Modifications—consistency, nutrients • Feeding techniques. • Diet in diseases—obesity, diabetes mellitus, CVD, underweight, renal diseases, hepatic disorders constipation, diarrhea, pre- and post-operative period

• Lecture cum discussion • Meal planning • Lab session on preparation of therapeutic diets

• Essay • Short answer • Very short answer

X

3 (T) Describe the rules and preservation of nutrients

Cookery Rules and Preservation of Nutrients • Cooking—methods, advantages and disadvantages • Preservation of nutrients • Measures to prevent loss of nutrients during preparation • Safe food handling and storage of foods

• Lecture cum discussion • Charts/slides

• Essay • Short answer • Very short answer

Contd…

Syllabus

Unit Time (Hrs)

xxi

Textbook of Nutrition and Dietetics for BSc Nursing Students

Unit Time (Hrs)

Learning objectives

Content

Teaching learning activities

• Food preservation • Food additives and food dulteration • Prevention of Food Adulteration Act (PFA) • Food standards XI

4 (T) Explain the methods of nutritional assessment and nutrition education

Nutrition Assessment and Nutrition • Lecture cum Education discussion • Objectives of nutritional assessment • Demonstration • Methods of assessment—clinical • Writing examination, anthropometry, nutritional laboratory and biochemical assessment assessment, assessment of dietary report intake including food frequency questionnaire (FFQ) method • Nutrition education—purposes, principles and methods

• Essay • Short answer • Evaluation of nutritional assessment report

XII

3 (T) Describe nutritional problems in India and nutritional programs

National Nutritional Programs and Lecture cum Role of Nurse discussion • Nutritional problems in India • National nutritional policy • National nutritional programs— vitamin A supplementation, anemia Mukt Bharat Program, Integrated Child Development Services (ICDS), Midday Meal Scheme (MDMS), National Iodine Deficiency Disorders Control Program (NIDDCP), Weekly Iron Folic Acid Supplementation (WIFS) and others as introduced • Role of nurse in every program

• Essay • Short answer • Very short answer

XIII

2 (T) • Discuss the Food Safety Guided reading on • Quiz importance of • Definition, food safety related Acts • Short answer food hygiene and considerations and measures food safety • Food safety regulatory measures in India—Relevant Acts • Five keys to safer food • Food storage, food handling and cooking • General principles of food storage of food items (ex. milk, meat) • Role of food handlers in food borne diseases • Essential steps in safe cooking practices

Food born diseases and food poisoning are dealt in Community Health Nursing I.

xxii

Assessment methods

Contents Preface to the Third Edition ............................................................................................................................................................ v Preface to the First Edition .............................................................................................................................................................. vii Acknowledgments ........................................................................................................................................................................... ix Special Features of the Book ......................................................................................................................................................... xv Syllabus ............................................................................................................................................................................................... xix

CHAPTER 1

Introduction to Nutrition

1–23

Terminology of Nutrition ........................................................................................................................... History of Nutrition ...................................................................................................................................... Concepts of Nutrition ................................................................................................................................. Importance of Food in Health and Disease ......................................................................................... Role of Nutrition in Maintaining Health ............................................................................................... Factors Affecting Food and Nutrition .................................................................................................... Malnutrition .................................................................................................................................................... Role of Food and its Medicinal Value ..................................................................................................... Classification of Nutrients .......................................................................................................................... Macronutrients and Micronutrients....................................................................................................... Organic and Inorganic Nutrients ............................................................................................................ Energy Yielding and Non-energy Yielding Nutrients....................................................................... Origin of Food ................................................................................................................................................ Food Groups ..................................................................................................................................................

CHAPTER 2

Carbohydrates

3 5 6 7 8 9 11 11 13 14 19 20 20 20

25–43

Classification of Carbohydrates .............................................................................................................. Caloric Value of Carbohydrates............................................................................................................... Recommended Dietary Allowances ..................................................................................................... Dietary Sources ............................................................................................................................................ Functions of Carbohydrates..................................................................................................................... Digestion and Absorption of Carbohydrates .................................................................................... Storage and Metabolism of Carbohydrates ...................................................................................... Energy .............................................................................................................................................................. Units of Energy ............................................................................................................................................. Energy Value of Food.................................................................................................................................. Calorie ............................................................................................................................................................. Energy Requirement of Different Categories of People ................................................................ Factors Affecting Energy Requirement ................................................................................................ Basal Metabolism.........................................................................................................................................

27 30 30 32 32 32 33 36 36 36 36 37 38 38

Textbook of Nutrition and Dietetics for BSc Nursing Students

Chapter 3

Proteins

45–57

Types of Amino Acids ................................................................................................................................. Classification of Proteins ........................................................................................................................... Recommended Dietary Allowance ....................................................................................................... Dietary Sources of Protein ........................................................................................................................ Essential Amino Acids ................................................................................................................................ Functions of Proteins.................................................................................................................................. Digestion, Absorption, Metabolism and Storage of Proteins ......................................................

CHAPTER 4

Fats

59–70

Composition of Fats .................................................................................................................................... Classification of Fats.................................................................................................................................... Caloric Value of Fats .................................................................................................................................... Recommended Dietary Allowances for Fats ...................................................................................... Dietary Sources of Fats .............................................................................................................................. Functions of Fats in Body .......................................................................................................................... Digestion, Absorption and Storage of Fats ........................................................................................ Metabolism of Fat ........................................................................................................................................

CHAPTER 5

Vitamins

xxiv

Minerals

61 61 63 63 63 65 65 66

71–103

Characteristics of Vitamins ....................................................................................................................... Functions of Vitamins ................................................................................................................................. Classification of Vitamins .......................................................................................................................... Vitamin C (Ascorbic Acid).......................................................................................................................... Thiamine (Vitamin B1)................................................................................................................................. Riboflavin (Vitamin B2) ............................................................................................................................... Niacin (B3) ....................................................................................................................................................... Pyridoxine (Vitamin B6) .............................................................................................................................. Cyanocobalamin (Vitamin B12) ............................................................................................................... Folate— Folic Acid (Vitamin B9) .............................................................................................................. Biotin (Vitamin B7) ....................................................................................................................................... Pantothenic Acid (Vitamin B5) ................................................................................................................. Vitamin A ........................................................................................................................................................ Vitamin D ........................................................................................................................................................ Vitamin E ......................................................................................................................................................... Vitamin K .........................................................................................................................................................

CHAPTER 6

46 47 49 50 51 53 53

72 73 73 75 77 81 81 83 84 86 87 89 90 94 98 100

105–129

Classification of Minerals .......................................................................................................................... 107 Sources and Functions of Minerals ....................................................................................................... 108 Absorption, Synthesis, Metabolism, Storage and Excretion of Minerals ................................. 109

Balanced Diet

131–184

Balanced Diet ............................................................................................................................................... Principles of Balanced Diet ...................................................................................................................... Steps in Preparing a Balanced Diet ....................................................................................................... Elements ......................................................................................................................................................... Food Guides................................................................................................................................................... Food Groups .................................................................................................................................................. Food Exchange System.............................................................................................................................. Recommended Dietary Allowance ....................................................................................................... Nutritive Value of Foods ............................................................................................................................ Meal Planning ............................................................................................................................................... Meal Planning for Different Categories of People ........................................................................... According to WHO and UNICEF Recommendation ......................................................................... Nutrition during Adulthood .................................................................................................................... Classification of Work Based on Occupation (ICMR, 1990) ........................................................... Nutrition during Pregnancy ..................................................................................................................... Anemia in Pregnancy ................................................................................................................................. Nutrition for Aged Person/Geriatric Nutrition................................................................................... Food Budget ..................................................................................................................................................

CHAPTER 8

Nutritional Deficiency Disorder

185–194

Malnutrition due to Proteins ................................................................................................................... Malnutrition due to Fat.............................................................................................................................. Childhood Obesity ...................................................................................................................................... Malnutrition due to Vitamins .................................................................................................................. Malnutrition due to Minerals...................................................................................................................

CHAPTER 9

Therapeutic Diet

132 132 133 133 134 134 137 144 150 158 159 168 169 170 173 177 179 181

Contents

CHAPTER 7

186 190 190 192 192

195–225

Objectives....................................................................................................................................................... Principles ........................................................................................................................................................ Modification in Therapeutic Diets ......................................................................................................... Therapeutic Diet for Different Categories........................................................................................... Special Feeding Methods ......................................................................................................................... Types of Therapeutic Diets in Various Disorders .............................................................................. Dietary Management in Cardiovascular Diseases ........................................................................... Dietary Management in Chronic Renal Failure ................................................................................. Dietary Management in Obesity ............................................................................................................ Dietary Management in Diabetes Mellitus......................................................................................... Dietary Management in Gout ................................................................................................................. Diet Management during Radiotherapy ............................................................................................. Patient Daily Diet According to Consistency .....................................................................................

197 197 197 198 201 204 205 206 208 210 211 213 214

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Textbook of Nutrition and Dietetics for BSc Nursing Students

Diet Management for Patient with Allergy ........................................................................................ Nutrition in Liver Disease .......................................................................................................................... Dietary Management in Liver Disease ................................................................................................. Dietary Management in Gastrointestinal Disorders ....................................................................... Naturopathy ..................................................................................................................................................

CHAPTER 10 Cookery Rules and Preservation of Nutrients

227–262

Objectives of Cooking................................................................................................................................ Basic Principles of Cooking ...................................................................................................................... Purposes of Cooking .................................................................................................................................. Methods of Cooking ................................................................................................................................... Microwave Cooking .................................................................................................................................... Solar Cooking ................................................................................................................................................ Food Processing ........................................................................................................................................... Preserving Nutrients in Food ................................................................................................................... Food Hygiene ................................................................................................................................................ Food Toxicity.................................................................................................................................................. Storage of Food ............................................................................................................................................ Storage Conditions ..................................................................................................................................... Technology ................................................................................................................................................... Storage of Dry Foods .................................................................................................................................. Principles of Food Storage........................................................................................................................ Food Preservation........................................................................................................................................ Principles of Food Preservation .............................................................................................................. Food Additives .............................................................................................................................................. Food Adulteration ....................................................................................................................................... Food Standards ............................................................................................................................................ Food Laws in India ....................................................................................................................................... Beverages and Other Food Preparation .............................................................................................

CHAPTER 11 Nutritional Assessment and Nutrition Education

228 228 229 229 233 234 236 237 240 242 244 245 246 247 248 249 251 252 254 256 257 260

263–272

Objectives of Nutritional Assessment .................................................................................................. Methods of Nutritional Assessment ..................................................................................................... Principle of Nutrition Education ............................................................................................................. Purposes of Nutritional Education ........................................................................................................ Methods of Nutrition Education ............................................................................................................ Role of Nurse in Nutritional Care............................................................................................................

xxvi

214 216 216 217 221

264 264 270 270 270 271

273–301

Various Nutritional Programs Running in India ................................................................................ Anemia Mukt Bharat Program................................................................................................................. Weekly Iron and Folic Acid Supplementations ................................................................................. National and International Agencies Working toward Food/Nutrition ................................... Road to Health Card/Growth Chart .......................................................................................................

CHAPTER 13 Food Safety

274 281 286 287 298

Contents

CHAPTER 12 National Nutritional Program and Role

303–306

5 Keys to Safer Food.................................................................................................................................... 304 Annexures ..................................................................................................................................................... 307 Index .............................................................................................................................................................. 337

xxvii

Nutrition and Dietetics in a Nutshell

Types of Carbohydrates Concentrated forms of simple and compound sugars are a poor source of energy. They get into the blood too fast and cause an insulin over-reaction.

•

•

•

Simple sugars: Monosaccharide—single sugar unit ƒ Glucose: Blood sugar ƒ Fructose: Mostly fruits, berries and honey ƒ Galactose: Does not occur free in nature, it is always bonded to something else. Compound sugars: Disaccharide—two sugar units ƒ Sucrose: Sugar cane and sugar beets ƒ Maltose: Germinating seeds ƒ Lactose: Milk sugar Complex carbohydrate (starch): Polysaccharide—many sugar units.

Textbook of Nutrition and Dietetics for BSc Nursing Students

Processed Sugar • • • • •

It is not a nutrient but sometimes it is confused as a carbohydrate. All nutrients are removed from sugar through the refinery process. Contains empty calories: It has no any nutritional value, but it fills you up. Processed sugar robs the body of vitamins and minerals. Vitamins and minerals are used up when we digest the food—usually we are repaid by the nutrients in the food, but there are no nutrients in sugar. Sugar is hidden in many labels under a variety of different names. Add all the sugar together and they equal to the number one ingredient: Brown sugar, dextrose, beet sugar, maltose, glucose, corn syrup, fructose, molasses, galactose.

Processed Sugars Effect on Behavior • • • • • • •

First: Hyper activeness due to speed that sugar gets into the blood. Next: Drops glucose level due to an insulin over-reaction. Then: Low sugar levels in the blood shuts off the ‘cerebral brain’ which controls learning, attention span, moral values, etc. Now, the animal (hypothalamus) brain is left to run the body which controls survival instincts and selfgratification. Hypoglycemia: Low blood sugar due to an over secretion of insulin. Symptoms begin 2–5 hours after a meal. Symptoms: Rapid heartbeat, sweating, lack of energy, dizziness, shaking, faintness, and headaches.

Test for the Carbohydrates Test

Purpose

Molisch test

General test for all Carbohydrates

Benedict’s test

Test for reducing substances

Barfoed’s  test Moore’s test Fehling’s test

Test to differentiate monosaccharides and disaccharides

Seliwanoff’s test Foulger’s test rapid furfural test

Test to differentiate aldoses and ketoses

Feulgen staining

Test to detect deoxy sugar

Bial’s test

Test for pentoses

Mucic acid test

Test for galactose

Protein Requirements

xxx

• • • •

The Indian Council of Medical Research (ICMR) recommended 1 g/kg/day for an Indian adult. Average adult male—60 g/day and female—55 g/day. Pregnant women require additional 15 g/day and lactating women 25 g/day protein Infants and children require 2–2.2 g/kg/day for normal health and development.

Fibrous protein

Globular protein

Elongated/needle-shaped/cylindrical/rod-like

Spherical/oval/spheroidal

Minimum solubility in water

Easily water soluble

Mainly structural proteins (collagen, elastin, and keratin)

Metabolic proteins (transport protein—albumin and globulin; Hb; myoglobin, antibodies, enzymes and hormones)

Conjugated Protein Conjugated protein

Constituents

Example

Glycoproteins

Protein + carbohydrate

Blood group antigens, immune globulins, mucin of saliva, plasma proteins (except albumin, TSH, FSH, LH)

Lipoproteins

Protein + lipids

LDL, HDL, VLDL, chylomicrons

Nucleoproteins

Protein + nucleic acids

Histones

Phosphoprotein

Contains phosphorus

Casein of milk and vitelline of egg yolk

Nutrition and Dietetics in a Nutshell

Shapes of Proteins

Classification of Amino Acids Essential amino acids

Non-essential amino acids

Leucine

Alanine

Isoleucine

Aspartic acid

Histidine

Glutamine

Lysine

Glutamic acid

Methionine

Arginine

Phenylalanine

Asparagine 

Tryptophan

Serine

Valine

Cysteine

Threonine

Glycine Proline Tyrosine

Types of Fats • •

Saturated fats: Solid or semisolid at room temperature ƒ A fatty acid carrying the maximum possible number of hydrogen atoms. ƒ Source: Mostly from animal products—meats, poultry, fish, milk, cheese and eggs. Polyunsaturated fats: Liquid at room temperature: ƒ A fatty acid that has two or more hydrogen bonds missing

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•

•

•

ƒ Source: Mostly from plants ƒ Lowers cholesterol, but also slightly lowers HDL (good cholesterol) ƒ They supply essential fatty acids. Monounsaturated fats: Liquid at room temperature: ƒ A fatty acid that has one hydrogen bond missing ƒ Slightly lowers LDL cholesterol, but some studies show that it may slightly raise HDL ƒ Other studies show its effect on HDL in neutral ƒ Canola oil had both polyunsaturated a monounsaturated fat. Fish oils: Omega-3 polyunsaturated fatty acids that come from fish: ƒ They do not have much effect on cholesterol. ƒ They lower the total amount of fat in the blood (reduce triglycerides). ƒ They help prevent blood clots. ƒ Smart to eat fish 2 or 3 times a week. Trans fatty acids: The process of adding hydrogen to unsaturated fats to make it more solid and resistant to chemical change: ƒ Causes it to lose its polyunsaturated character and health benefits. Example: Butter: Margarine (partially hydrogenated vegetable oil).

Two Types of Cholesterol 1. Low-density lipoproteins (LDL): Bad cholesterol: ƒ Fat in the blood stream that is on its way to cell for storage, (including the cells that line the artery walls) ƒ Saturated fat causes the body to produce LDL 2. High-density lipoproteins (HDL) good cholesterol: ƒ Fat in the bloodstream that is en route to the liver where it is processed and excreted from the body. ƒ HDL works to minimize the harmful effects of LDL by causing it to be removed from the blood stream and excreted. ƒ Cannot get HDL from the foot you eat. ƒ The trick is to get your body to make it: ƒ Losing weight ƒ Not smoking ƒ Aerobic exercise

Normal Value of Different Lipoproteins • • • •

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• •

Total blood cholesterol should be less than 200 mg/dL (total blood cholesterol is the sum of the cholesterol in three lipoprotein) LDL cholesterol should be less than 130 mg/dL HDL cholesterol should be more than 40 mg/dL Organs whose major energy source is glucose is: Brain, RBC (in both in fed and starving state), cornea, retina, renal medulla and testes. Canola oil had both polyunsaturated and monounsaturated fats. PUFA are mostly found in vegetable oils and saturated fats mainly in animal fats.

• • • •

Trans fatty acids: the process of adding hydrogen to unsaturated fats to make it more solid and resistant to chemical change. Water soluble vitamins are excreted in urine and hence cannot accumulate to toxic levels in the body. All B-complex vitamins wash out easily from the body except B12 and folate (stored in liver) Sulfur containing vitamins are thiamine (B1) and biotin Folic acid and vitamin B12 are called hematopoietic vitamins since they are required for normal maturation of RBCs because of their role in DNA synthesis.

Kwashiorkor: The term Kwashiorkor is derived from the Ga language of Chana and means “the sickness of the weaning”. Williams first used the term in 1993, and it refers to an inadequate protein intake with reasonable caloric (energy) intake. Marasmus: The term, Marasmus, is derived from the Greek word ‘marasmos’, which means withering or wasting.

Nutrition and Dietetics in a Nutshell

•

Fluorine is a double-edged sword: Inadequate intake is associated with dental caries, whereas excess intake with dental and skeletal fluorosis. Level >1.5 ppm: Dental fluorosis (mottling) Level 3–6 ppm: Skeletal fluorosis Level >10 ppm: Crippling fluorosis

•

•

•

Double fortified/Twin salt fortified: ƒ Contains 40 mcg Iodine and 1 mg iron per gram of salt ƒ Developed by National Institute of Nutrition. ƒ The most recommended defluoridation method is Nalgonda Technique. Defluoridation is removal of excess fluorides from water. ƒ Best source of vitamin D is sunlight. ƒ Wernicke’s encephalopathy is due to the deficiency of vitamin thiamine. ƒ Magenta red tongue seen in the deficiency of riboflavin. ƒ Richest Source of essential fatty acids (EFA): Safflower oil Pellagra is characterized by 4Ds i. Diarrhea ii. Dementia iii. Death iv. Dermatitis ¾ First sign of vitamin A deficiency is conjunctival xerosis (dryness of eye) ¾ Kanawati index is used for protein-energy malnutrition.

Vitamins are Divided into Two Groups 1. Fat soluble vitamin (vitamin A, D, E, K) 2. Water soluble vitamin (vitamin B group & C) ƒ Fat-soluble vitamins deficiency mainly occurs in disease that interferes with the digestion of fat (such as steatorrhea), but it accumulates in organs, like the liver when taken in excess. ƒ Water-soluble vitamins are readily lost from the body in urine and sweat.

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ƒ Deficiency of any vitamin causes specific deficiency disease except vitamin E, which deficiency disease is yet not known.

ƒ Three vitamins, like pro-vitamin A (carotene), vitamin C & vitamin E are termed anti-oxidant vitamin because they inactivate or remove free radicals (o-) from body. Based on response to heat, vitamin is divided into the following two groups: 1. Heat stable vitamins (A, D, E, K) 2. Heat unstable vitamins [vitamin c and some vitamin B like thiamine (B1) and folic acid]

Vitamin A Deficiency Disease ƒ Night blindness: Deficiency of vitamin A causes night blindness. It is first clinical symptom. ƒ Conjunctival xerosis: Dryness of conjunctiva (a membrane which covers the eyeball and inner sides of eyelids). It is the first clinical sign of vitamin A deficiency.

ƒ Bitot’s spot: Triangular, pearly white or yellowish, foamy spots on conjunctiva on either side of cornea. ƒ Corneal xerosis: The cornea becomes dry and eventually opaque. It is a serious condition. ƒ Keratomalacia: Liquefaction or extremely softening of cornea called keratomalacia. It is a grave medical emergency.

ƒ All above ocular manifestation of vitamin A deficiency from night blindness to keratomalacia called xerophthalmia (dry eye).

ƒ The most frequent cause of blindness in developed countries are accidents, glaucoma, diabetic retinopathy, hypertensive retinopathy and cataract.

ƒ In south-east Asia, like India, the principal cause of blindness is cataract, responsible for 62.6% of all ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ

cases. Vitamin A deficiency, which is responsible for most of childhood blindness now declining slowly. There are two major forms of vitamins K—K1 & K2. Vitamin K1 mainly is found in fresh fruits and green vegetables, like dark green vegetable. Vitamin K2 is synthesized by intestinal bacterial flora. Cow milk (60 g/L) is the richest source of vitamin K, than human milk (15 g/L). Long-term administration of antibiotic may cause suppression of intestinal flora and may cause a deficiency of vitamin K. Vitamin K is stored in the liver. Vitamin K is essential for production of clotting factor II, VII, IX and X, so in deficiency of vitamin K, blood clotting time (CT) becomes prolonged. The newborn infants are deficient in vitamin K due to deficient intestinal bacterial flora and minimal stores of prothrombin (because of immature liver) at birth. IM injection (into vastus lateralis muscles) of menadione (vitamin K3, a synthetic vitamin that can be converted in the body to active vitamin K) 0.1–0.2 mg use at birth. Within the kidney, vitamin K acts to inhibit calcium oxalate stone formation.

Iron Requirement

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ƒ Adult male—28 mg/day (ICMR, 2001) ƒ Adult male—17 mg/day (ICMR, 2010) ƒ Adult female—30 mg/day (ICMR, 2001)

Nutrition and Dietetics in a Nutshell

ƒ Adult female—21 mg/day (ICMR, 2010) ƒ Pregnant women—38 mg/day (ICMR, 2001) ƒ Pregnant women—35 mg/day (ICMR, 2010)

Dietary Sources of Energy Source

Energy in kcal

Energy in kJ

1 g of protein

4 kcal

17 KJ

1 g of carbohydrate

4 kcal

17 KJ

1 g of fat

9 kcal

37 KJ

Recommended Daily Allowance for Energy According to 2010 • • • • • • • • •

Reference man (Weight 60 kg)—sedentary work—2425 kcal Moderate activities—2875 kcal Hard work—3800 kcal Reference female (weight 55 kg)—sedentary work—1875 kcal Moderate activities—2225 kcal Hard work—2925 kcal Pregnant Female—350 kcal/day additional energy Lactating Mother (0–6 month)—600 kcal/day Lactating Mother (after 6 month)—520 kcal/day

Principal Clinical Manifestation of Kwashiorkor and Marasmus Clinical features

Muscle wasting

Edema

Weight according height

Appetite

Serum albumin

Deficiency

Marasmus

Obviously

None

Very low due to loss of subcutaneous fat

Usually good

Slightly decreased

Severe energy deficiency

Low but hidden by edema

Poor

Very low, less than 3 g/dL (total protein—6–8 g/dL albumin—3.5–5.5 g/dL, globulin—1.5–3 g/dL)

Severe protein deficiency

Kwashiorkor Present but Pitting edema on lower hidden by edema leg, face and abdomen (due to decreased osmotic pressure in to blood)

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Protein Energy Malnutrition (PEM) Features

Skin change

Hair change

Face

Marasmus

Appears loose and sags

No

Sunken face and eye (monkey-like face)

Kwashiorkor

Flaky paint dermatosis

Band of hypopigmented and normal pigmented hair called “flag sign”

Moon face

Types of Marasmus According to progressive loss of subcutaneous fat from:

• • • •

Grade-1—buttocks Grade-2—grade 1+ axilla and groins Grade-3—grade 1+ grade 2 + abdomen, chest, spine Grade-4—grade 1+ grade 2 + grade 3 + buccal pad

Classification of PEM According indian academy of pediatrics:

• • • •

1st degree—weight between 70–80% of expected 2nd degree—weight between 60–70% of expected 3rd degree—weight between 50–60% of expected 4th degree—weight below 50% of expected

Mid-arm Circumference • • •

No more change in mid-arm circumference between first 5 years of age. Mid-arm circumference measure uses to assess nutrition status of children between 1 and 5 years of age. Not use in less than 1 year children

Shakir’s Tape • • •

Normal nutritional status—more than 13.5 cm (green) Border line PEM—12.5–13.5 cm (yellow) Severe PEM (wasted)—less than 12.5 cm (red)

Midday School Meal

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Food substance

Amount

Cereals and millets

75 g/day/child

Pulses

30 g/day/child

CHAPTER

1

Introduction to Nutrition

LEARNING OBJECTIVE Define nutrition and its relationship to health

CHAPTER OUTLINE Concepts Š Terminology of Nutrition Š History of Nutrition Š Concepts of Nutrition Š Importance of Food in Health and Disease Š Role of Nutrition in Maintaining Health Š Factors Affecting Food and Nutrition Š Malnutrition Š Role of Food and its Medicinal Value Nutrients Š Classification of Nutrients Š Macronutrients and Micronutrients Contd…

Textbook of Nutrition and Dietetics for BSc Nursing Students

Š Organic and Inorganic Nutrients Š Energy Yielding and Non-energy Yielding Nutrients Food Š Origin of Food Š Food Groups

KEY TERMS Š BMR (Poor nutrition): The basal metabolic rate (BMR) is the measurement of an organism’s energy expenditure when at rest. Amount of minimum energy required to carry on the basic involuntary work of the body is known as BMR. Š Carbohydrates: The organic compounds, sugar, starches and dietary fiber that occur in plant foods and provide energy to body. Š Dietetics: Practical applications of the principles of nutrition, including the planning of meals for well and sick. Š Energy: Capacity to do work. Š Food taboos: Religion-based food habits like vegetarianism in Hindu society and prohibition of pork in Muslim society. Š Health: State of complete physical, mental and social well-being and not merely an absence of disease and infirmity (WHO). Š Lipid: A small water insoluble biomolecule generally containing fatty acids, sterols or isoprenoid compounds. Š Macronutrients: Required in large quantity and from the bulk of our food, e.g., proteins, fats and carbohydrates. Š Malnutrition: Impairment of health resulting from a deficiency, excess or imbalance of nutrients. Š Micronutrients: Required in small amounts but play an important role in the regulation of metabolic activities, e.g., vitamins and minerals. Š Nutrient: A substance essential for the growth, maintenance, function and reproduction of a cell or of an organism. Š Nutrition: The science of food and its relationship to health. Š Protein: A macromolecule composed of one or more polypeptide chains, each with a characteristic sequence of amino acids linked by peptide bonds and is essential for muscle mass. Š Vitamin: An organic substance required in small quantities in the diet that generally functions as a component of a coenzyme.

INTRODUCTION In ancient times, even before the dawn of civilization, human beings believed in live to eat or eat to live notion, because probably, these were the first and fundamental lessons they could learn from the experience of existence and survival. According to Maharshi Charaka, the sage and physician of ancient times, emphatically observed: “The body is the outcome of the food”, the distinction between ease and disease arising, totally or partially, due to faulty food or diet” thus laying down the bedrock of foods, nutrition and health relationship. The study of how food nourishes the body is nutrition. It is a field of knowledge that consists of facts which scientists have obtained by systematically observing what people eat and noting how healthy they are. These facts have also been obtained and validated by experimentation to see the effects of various foods and diets on human health.

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TERMINOLOGY OF NUTRITION Nurses are important members of health team and committed to maintaining the good health status of the people. They are providing continuity of care in community settings also. Some important terms to understand the concept of nutrition are as follows: •

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• • • •

•

• •

• •

•

Food: Food refers to the materials of solid or liquid nature which, when ingested, serve one or more functions of growth, maintenance and energy provision. Consuming foods appropriate in both content and kind promotes nutrition and health. Health: According to World Health Organization (WHO), health is defined as the “state of complete physical, mental and social well-being and not merely the absence of disease or infirmity”. Nutrition: The science of food, the nutrients and the substances, their action, interaction and balance in relation to health and disease, the process by which the organism (i.e., body) ingests, digests, absorbs, transports, utilizes and excretes food substances. Or The process of taking food and using it for growth, metabolism, and repair. Nutritional stages are ingestion, digestion, absorption, transport, assimilation and excretion. Nutrients: Nutrients are the components in food that are essential for the body in suitable amounts. These include proteins, fat, carbohydrates, vitamins, minerals and water. Nutritionist: A person who advises about nutrition or works in the field of foods and nutrition. Nutrition labels: A label format that must be included on foods under certain circumstances, such as when nutrients are added to foods or when a nutritional claim is made for the food. Nutritional status: The condition of health of the individual as influenced by the intake and utilization of the nutrients is called nutritional status. It can be determined by the medical and dietary history, physical examination and through appropriate biochemical investigations. Nutritional index: Nutritional indices measure different aspects of growth failure (wasting, stunting and underweight). The main nutritional indices for children are weight-for-height, sex and height, height-for-age, weight-for-age, all compared to values from a reference population. In emergency situations, weight-for-height is commonly used for nutritional assessments. Nutritional requirement: Nutritional requirement refers to the amount of energy, protein, fat and micronutrients needed for an individual to sustain a healthy life. Nutritional screening: Nutritional screening refers to the individual-level assessment where each person is measured in order to identify and refer those needing further check-ups or such services as supplementary or therapeutic feeding. Nutrition surveillance: Nutrition surveillance is defined as the regular collection of nutrition information that is used for making decisions about actions or policies that will affect nutrition. Malnutrition: Malnutrition is the condition resulting from dietary nutrient deficiency, excess or imbalance of nutrients. It can either under nutrition or over nutrition: ƒ Under nutrition refers to the deficiency of calories and/or one or more essential nutrients, or ƒ Over nutrition refers to an excess of one or more nutrients especially calories. Balanced diet: A diet containing all essential (macro and micro) nutrients in optimum quantities and in appropriate proportions to meet the requirements.

Chapter 1  Introduction to Nutrition

CONCEPTS

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Textbook of Nutrition and Dietetics for BSc Nursing Students

• • • • • • •

•

• • • • • • • • • • •

•

4

Macronutrients: Fat, protein and carbohydrates that are needed for a wide range of body functions and processes. Micronutrients: Essential vitamins and minerals required by the body in small amounts throughout the life cycle. Food fortification: The addition of micronutrients to a food during or after processing to amounts greater than were present in the original food product. This is also known as ‘enrichment’. Food security: When all people at all times have access to sufficient, safe, nutritious food to maintain a healthy and active life (1996 World Food Summit definition). Obesity: A condition characterized by excess body fat, usually defined as body weight 20% above the desirable level. Wasting: It refers to the result of weight loss associated with an acute period of food shortage or disease and is defined as low weight for height. Chronic energy deficiency (CED): It is the condition of underweight among adults as a result of prolonged negative energy balance. It is measured through body mass index (BMI). A BMI value of less than 18.5 indicates CED in adults. Body mass index (BMI): It is the ratio of weight for height, which is often used to estimate body fat. It is obtained by dividing the weight in kilograms by the square of the height in meters. BMI is not an appropriate assessment for growing children, sedentary individuals or women who are pregnant and lactating. Calorie: Unit used to indicate the energy value of foods. Quantitative requirements are expressed in terms of energy, i.e., kilocalorie (kcal). Newer unit for energy is K joules. Kilocalorie (kcal): It is the amount of heat required to raise the temperature of 1 L of water by 1˚C; 1 kcal = 1000 cal. Basal metabolic rate (BMR): It is the rate of metabolism when an individual is at complete rest in a warm environment and is in postabsorptive state (12 hours after taking a meal). Therapeutic diet: It is the modification of food either in consistency, preparation or nutrients to meet the special nutritional needs of a person suffering from a particular disease or condition. Energy metabolism: The reactions by which the body obtains and spends the energy from food. Metabolism: The sum total of all the chemical reactions that go on in living cells; also the transformation by which energy is made available for the use of the organism. Digestion: Digestion is the mechanical and chemical process of breaking down of food into its smaller molecules, which can then be absorbed into the blood stream. Triglycerides: The scientific name for the common form of fat, found in both the body and in foods. Most body fat is stored in the form of triglycerides. Vitamins: Organic, essential nutrients required in small amounts. Minerals: Inorganic elements; some minerals are essential nutrients required in small amounts. Antioxidants: Antioxidants are synthetic or naturally occurring substances found in some foods and drinks. They are added to food to prevent oxidation, e.g., vitamin C in fruit juice prevents oxidation. They also may have protective effects on our body by counteracting the negative effects of free radicals (reactive atoms that may lead to cancer and other age-related diseases). Recommended dietary allowance (RDA): It is the amount of dietary energy and nutrients considered as sufficient for maintaining good health by the people of a country.

Humans have evolved as omnivorous hunter—gatherer over the past 250,000 years. The diet of early modern humans varied significantly depending on location and climate. The diet in the tropics tended to depend more heavily on plant foods, while the diet at higher latitudes tended more toward animal products. Agriculture developed about 10,000 years ago in multiple locations throughout the world, providing grains, farming also provided milk and dairy products, sharply increased the availability of meats and diversity of vegetables.

Landmarks in the Fields of Food and Nutrition • • • • • • • • • •

• •

• • • • • • • •

Around 3000 BC: Vedic texts mention of scientific research on nutrition. The Bibles Book of Daniel recounts first recorded nutritional experiment. Around 400 BC: Hippocrates said, “Let food be your medicine and medicine be your food”. 16th century: Leonardo da Vinci compared metabolism to a burning candle. 1747: Dr James Lind performed scientific nutrition experiment, discovering that lime juice saved sailors who had been at sea for years from scurvy, bleeding disorders. 1770: Antoine Lavoisier, the “Father of Nutrition and Chemistry”, discovered the details of metabolism, demonstrating that the oxidation of food is the source of body heat. 1790: George Fordyce recognized calcium as necessary for food survival. 19th century: The elements carbon, nitrogen, hydrogen and oxygen were recognized as primary components of food. 1840: Justus Liebig discovered the chemical makeup of carbohydrates (sugars), fats (fatty acids) and proteins (amino acids). 1860s: Claude Bernard discovered that body fat can be synthesized from carbohydrate and protein, showing that energy in body glucose can be stored as fat or a glycogen. 1880s: Takaki observed that Japanese sailor developed beriberi but British sailors and Japanese naval officers did not. Adding various types of vegetable meals to the diet of Japanese sailor prevented the disease. 1896: Baumann observed iodine in thyroid gland. 1912: Casimir Funk coined the term vitamin because he thought that these unknown substances were preventing beriberi and pellagra. The word vitamin has been dervied from Latin word, ‘vita’, means ‘life’ and ‘amine’ means containing amino acids. 1913: Elmer McCollum discovered the first vitamins fat-soluble vitamin A and water-soluble vitamin C. 1919: Sir Edward Mellanby incorrectly identified rickets as vitamin A deficiency, because he could cure it in dogs with Cod liver oil. 1922: McCollum destroyed the vitamin A in Cod liver oil but found it still cured rickets, thus identifying vitamin D. 1927: Adolf synthesized vitamin D, for which he won the Nobel Prize in Chemistry. 1928: Albert isolated ascorbic acid. 1930s: William identified essential amino acids, necessary protein components which the body cannot synthesize. 1941: The National Research Council established the first recommended dietary allowances. 1992: The US Department of Agriculture introduced the food guide pyramid.

Chapter 1  Introduction to Nutrition

HISTORY OF NUTRITION

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Textbook of Nutrition and Dietetics for BSc Nursing Students

Effect of Modernization on Nutrition In recent times, dietary habits of an individual have undergone drastic changes. Due to our changing nutritional pattern, most chronic diseases are spreading worldwide. Lifestyle changes have influenced our lives so much so that we rarely have time to think whether we are eating healthy or not. Due to globalization, people are moving toward junk foods. Although people are aware of the health hazards caused by such diet, unfortunately measures taken are not as effective as they need to be. There are so many disease conditions prevailing due to modernization in our dietary pattern such as cardiac problems, obesity, food poisoning, diabetes mellitus, hypertension, etc. Traditionally the main aim of nutrition was to prevent and treat nutritional deficiencies and to provide energy to the body for various functions. Modern diet mainly “Junk food” simply means an empty calorie food. An empty calorie food means food which is high in calorie but lacks macro and micro nutrients such as carbohydrates, proteins, vitamins, minerals, amino acids and fiber. These food items do not contain nutrients that our body needs to stay healthy. What makes these foods to be called junk is that it contains high level of refined sugar, white flour, trans fat and poly-unsaturated fat, salt and numerous food additives. Consumption of such kind of food is due to increasing urbanization and industrialization in various countries. Addition to that, person’s levels of physical activity, their body composition and physique, life expectancy and patterns of disease also have impact on nutritional status of the individual in modern world. Balanced diet, personal hygiene and regular exercise are very important to maintain good health. Drug and alcohol abuse in modern urbanization has also put bad impact on the health of people. It is not impossible to win battle with junk foods against healthy foods. However, one gets addicted to the food readily. The main key problems due to modernization on health are: • •

Under nutrition causes nutrition deficiency and over nutrition leads to obesity, hypertension, hyperlipidemia, diabetes and cancer. Lack of proper nutrition also impacts the nutrition of an individual’s immunity. Low immunity is observed in infants, children and elderly and in individuals with diseases and serious nutrition defects.

CONCEPTS OF NUTRITION According to Oxford Dictionary, term “concept” means abstract idea, general belief/view. To know the concepts behind nutrition, we need to understand some definitions and guidelines.

General Nutrition Concepts/Definitions This may seem so basic, but these words and principles are the foundation to understanding and practicing good nutrition. •

•

6

Calories: One calorie is the amount of heat that increases the temperature of one kilogram of water by 1°C. In other words, calories represent the amount of energy that a particular food provides to our bodies once it is digested. Excess calories are stored as fats. Over the time, storage of these extra calories will lead to obesity if not burned properly through physical activity. Calorie density: It is the amount of energy that a food provides per volume measure. Calorically certain foods are calorically dense foods.

• • • •

• •

Nutrient density: It is a ratio of nutrient content to the total energy content of food. Means how many nutrients a food is providing to individual as compared to amount of calories provided higher the nutrient density of food, more the food is better, e.g., spinach. Variety: A different food provides different nutrients. So for optimal nutrition, an individual must rely on variety of foods. Balance: One must eat foods from the entire food group daily for balanced diet. Balance the proteins, fats and carbohydrates in each meal. Moderation: Eat food in portions instead of eating one item in excess, eat each food in moderation or in other words in portions. Intake versus daily requirements: Compare your actual intake of food with your daily recommended diet. According to age, sex, weight, height and physical activity, make changes in your diet accordingly for healthy life. Human nutrition: Refers to provision of essential nutrients necessary to support human life and health. Malnutrition: It is a condition resulting from the deficiency, excess or imbalance of nutrients. It can be either under nutrition which refers to deficiency of calories of essential nutrients or over nutrition which refers to an excess of one or more nutrients, especially calories.

Chapter 1  Introduction to Nutrition

•

Basic Concepts of Nutrition • • • • • • • •

We eat food to live, to grow, to keep healthy and well and to get energy for work and play. Different nutrients when mixed together provide maximum benefits to an individual. Every nutrient has its specific role in body to perform. A single food itself cannot provide all nutrients required for full growth and health of individual. We need multiple food sources to complete our nutritional needs. Various kinds and combinations of food can lead to a well-balanced diet with proper nutrition. Requirement of nutrients depends upon age, sex, size, activity and state of health of an individual. Handling of food influences the amount of nutrient in food. Its safety, appearance and taste, etc. depend on its handling. Trained scientists or expert persons provide suggestions about nutrition.

IMPORTANCE OF FOOD IN HEALTH AND DISEASE Role of Food • •

Promotes health and prevents diseases Treats and controls disease condition

Food in the Prevention of Disease If a person takes balanced diet, i.e., the right kind of foods is consumed in the required amounts, he or she will maintain good health, provided no other factors intervene. Contrary to this, poor eating habits or eating too much or too little will result in poor health. Poor eating habits and malnutrition are like two sides of the same coin. • •

Reduced intake of food for specific nutrients leads to nutritional deficiency disorder such as proteinenergy malnutrition (PEM), vitamin A deficiency or anemia. Nutritional deficiency disorders such as PEM, vitamin A deficiency and anemia may lead to degenerative diseases. Fibers have a valuable role to play in the prevention of disease.

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Textbook of Nutrition and Dietetics for BSc Nursing Students

Food as Therapy Food as a whole and nutrients in medicinal form (oils, syrups, capsules and tablets) are used to treat disease. Diet is an important part of treatment for patients with metabolic disorders such as diabetes. Special dietary modifications are often necessary to maintain the lives of patients who have chronic kidney disease, heart, liver and gastrointestinal disorders. Similarly, dietary modifications are also essential in other situations such as burns, bone fracture and in surgical conditions. Deficiency of a single nutrient is rare. If it does exist, it can be corrected by adding the specific nutrient through the diet or supplementation.

Diseases have Different Origins •

Diseases are caused by nutrient deficiency. For example, protein-energy malnutrition, vitamin A deficiency, iron-deficiency anemia and other nutrient deficiency diseases. • Diseases are caused due to several factors out of which some are of food and nutrient related. For example, diabetes, coronary heart diseases, renal diseases, etc. Excessive consumption of sugar and refined carbohydrates precipitate diabetes in individuals who are genetically predisposed. Some diseases are not directly related to food and nutrients, for example, chicken pox, measles, malaria, infectious diseases, etc. Similarly, high intake of fats, especially saturated fats and cholesterol is believed to be a cause of deposition of fats in arteries which leads to narrowing of the vessels also known as atherosclerosis, a leading cause of cardiovascular diseases. In such diseases, diet cannot cure the disease but can prevent the progression and associated complications. Thus, diet therapy helps patient lead a quality life, without which the disease can become uncontrolled. Mild conditions can be controlled by diet alone. Some of these may be transmitted through food but food is not the root cause. In these conditions, diet therapy is either directly or indirectly prescribed. For example, in febrile conditions, high-energy and highprotein diet is advised due to increased basal metabolic rate.

ROLE OF NUTRITION IN MAINTAINING HEALTH Health is a state of complete physical, mental and social well-being and not merely the absence of disease and infirmity, according to WHO. Previously, the concept of health revolved around healing the sick and helping them to maintain their health by educating them regarding foods that can build strength in their bodies. Without good nutritional status of their citizens, no country can develop economically, socially and politically stable. Nutrition affects human health from birth to death, which may be understood by following points: •

•

•

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Foods rich in nutrient values provide strong immunity to individuals to fight against various dreadful diseases, like tuberculosis. Similarly, on other hand, poor nutritive food may lead to malnutrition. Also postoperative patient’s good nutrition helps in wound healing and quick child’s recovery. Good nutrition is important for optimal growth and development of child. Child’s physical growth, mental growth, his learning ability, behavior—all are affected by good nutrition. During pregnancy period, mother requires good amount of nutritional food for the prevention of growth retardation and other abnormalities of the fetus. An old person requires special nutrition to minimize age related disability and functional impairment. There are so many diseases which are directly or indirectly related to food and nutrition of an individual, such as diabetes mellitus, coronary heart diseases, renal diseases, etc. Excessive sugar intake and high intake of saturated fats and cholesterol precipitate diabetes and coronary heart diseases in individuals who are predisposed. In such diseases, diet cannot cure the disease but can prevent the progression and the associated complications.

There are various deficiency diseases which are caused by poor nutrition called nutritional deficiency diseases, like protein-energy malnutrition, goiter, anemia, blindness, etc. To prevent all these diseases, good nutrition is essential. If we structure our lifestyle with proper nutrition, healthy habits and exercise program, it will affect our health positively and will reduce medical care expenditures.

FACTORS AFFECTING FOOD AND NUTRITION The term, “food” is conventionally used while referring to the materials of solid or liquid nature which when ingested; serve one or more functions of growth, maintenance and energy provision. Consuming food must be appropriate in both content and kind that promotes nutrition and health. The social scientists, anthropologists and cultural geographers, etc. have been concerned with man’s culture, social activities and food habits. As we all know food habits develop from childhood period and continue thereafter throughout the life. A number of factors influence people’s food habits in their journey of life. These factors are as follows:

Chapter 1  Introduction to Nutrition

•

Socioeconomic Factors Fundamental need of life is nourishment through food. It depends upon family resources for adequate and nutritive food. Income of family decides the variety and amount of food to be purchased. Families having high income resources choose a high quality and a variety of foods in their diet, on the other hand, poor family having low income and large families, rely on cheaper variety of foods; which affects their nourishment and lead to malnutrition in many cases.

Cultural Factors Every culture has its own customs and beliefs regarding nutritional practices. Culture is transmitted from one generation to another. For some cultures food is a basic need to satisfy hunger but for some, cultures, it is a time for family and social sharing. Various religions of the world have some influence on the food habits. For example, Muslims are forbidden from eating pork and Hindus from eating beef. Vegetarians are given a place of honor in Hindu society. All these cultural beliefs affect the health of individuals directly or indirectly.

Traditional Factors Even in 21st century, traditional beliefs in food habits are still prevalent with larger population of our country who are illiterate or ignorant regarding the nutritive value of food. A social or religious custom prohibiting or restricting a particular practice is known as Taboos. Similarly, there are some food Taboos in our tradition or Indian culture which affect the health of vulnerable groups, like pregnant women and small children. On comparative basis, many food Taboos seem to make no sense at all, as to what may be declared unfit by one group may be declared fit by the other group. For example: • • • •

In India, consumption of papaya fruit by pregnant is believed to lead to abortion. Consumption of garlic by lactating mother will increase milk production. Classification of food into hot and cold food. Hot food produces more heat in body and leads to development of boils, whereas cold food leads to the development of cold, sore throat, etc. Eating clay or starch by pregnant womens is known as pica. There is a belief that baby will not be normal if one does not eat clay or starch.

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Textbook of Nutrition and Dietetics for BSc Nursing Students

System of Distribution Adequate availability of food at natural level does not necessarily lead to adequate availability in all the religions, especially in the deficit and inaccessible regions of country. Market imperfections (like transport problem, inadequate storage capacity, availability of credit and insurance) and governmental restrictions hamper free movement of food grains across intra-national borders. Due to these reasons, cost of food grains rises and availability of nutritional food decreases. Consumers in the deficient regions have to pay higher prices for food grains than those in the surplus regions, if there will not be proper distribution of food grains. For the poor consumers in the deficient regions, higher prices of food grains may imply lower consumption of food and consequent poor intake of nutrition.

Lifestyle and Food Habit Factors Evidence suggests that the habit of regularly eating healthy and well-balanced meals contributes to sustained weight maintenance, a better mood, increased energy level, positive inspiration to others and the potential for a quality of life. Scientific studies have shown that proper timing of food and choosing healthy foods can reduce the risk of heart disease, cancer and other diseases. A healthy diet is a lifestyle, not a fad that is dangerous or difficult to maintain. Abundant evidence suggests that the most healthy diets set aside animal products and also reduce fats in general, while including large amounts of vegetables and fruits. There is an impact of several lifestyle factors on health of an individual, for example, impact of age, weight, smoking, diet, exercise, psychological stress, alcohol consumption and exposure to environmental pollutants. • • •

•

Psychological stress: Stress is a feeling of strain and pressure. Small amounts of stress may be desired, beneficial and even healthy. Excessive amounts of stress, however, may lead to bodily harm. Stress can increase the risks of strokes, heart attacks, ulcers and mental disorders such as depression.

•

Alcohol consumption: Long-term use of alcohol is capable of damaging nearly every organ and system in the body. The food we eat gives our body the information and materials they need to function properly. If we do not get the right information, our metabolic processes suffer and our health declines. In short, what we eat is precursor to our health. Production and transport: Locally grown foods are consumed more and the availability of the locally grown produce is cheaper. It is readily available and hence forms the staple diet. Superstition: Many people try to avoid many foods due to their superstitions, e.g., papaya is avoided during pregnancy, as it is believed to cause abortions. Similarly, pregnant women drink milk with saffron to have a fair baby. Geographical area: People in the coastal areas of Karnataka, Kerala, Goa and West Bengal consume lots of sea food. Rice is the staple food in Andhra Pradesh and Tamil Nadu, as rice grows well in tropical areas. Wheat is the staple food in northern and eastern regions, as wheat is the main crop in temperate regions.

• •

•

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Age: Young children requires more protein for their growth and development and adolescents require more calories than adults. Weight: Obesity is associated with a range of adverse health consequences, widely recognized are the increased risk of cardiovascular disease, diabetes and some cancers. Exercise: There are strong scientific evidence that being physically active can help individual to lead a healthier and happier life. People who do regular activity/exercise have lower risks of many chronic diseases, such as heart disease, type-II diabetes, stroke and some cancers. It also boosts self-esteem, mood, sleep quality and energy, as well as reduces risk of stress and depression.

•

Specific dynamic action of food (SDA): It has been found that there is 8% increase in the production of energy in the form of heat after taking food. This is not due to digestion or absorption but due to stimulating effect of food on the basal metabolism. This stimulating effect is known as specific dynamic action of food. It varies according to different nutrients, e.g., SDA of carbohydrate is 5–6%, protein is 3%, fat is 4% and mixed diet is 12%. Physiological state: There is increased demand of food in certain physiological conditions, like in pregnant women, lactating mother, etc., due to increased BMR. The need of extra energy is associated with deposition of tissues during pregnancy and secretion of milk during lactation.

MALNUTRITION Details have been discussed in chapter 8. Please refer to the chapter.

Chapter 1  Introduction to Nutrition

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ROLE OF FOOD AND ITS MEDICINAL VALUE The nutrients in food enable the cells in our bodies to perform their necessary functions. Nutrients are the nourishing substances in food that are essential for growth and development of body. Nutrients give our bodies instructions about how to function. An individual needs to get a basic balance of nutrients every day for proper functioning of body. If a person takes balanced diet, i.e., the right kind of food in the required amounts, it will maintain good health and on the other hand, poor eating habits or eating too much or too little will result in poor health. Reduced intake of food leads to nutritional deficiency disorder such as PEM, vitamin A deficiency or anemia, which may lead to degenerative diseases.

Medicinal Value of Fruits in Diet Fruits are nature’s wonderful gift to mankind. They are life-enhancing medicines packed with vitamins, minerals, antioxidants and many phytonutrients. Fruits are composed of many antioxidants. These antioxidants protect us from many diseases, stress and cancers and help our body to develop capacity against these ailments by boosting our immunity level. • •

Fruits provide plenty of soluble dietary fibers, which help in lowering cholesterol and fat in body and help in smooth bowel movements to prevent constipation. Fruits richer in vitamins, minerals, micronutrients, antioxidants, help the body to prevent or at least prolong the natural changes of aging by protection from damage and rejuvenating cells, tissues and organs.

Medicinal Value of Dry Fruits Dry fruits are rich source of nutrients such as vitamins and minerals. Consumption of some dry fruits daily enhances the overall bioavailability of nutrients. Raisins, apricots, dates, figs are indeed very good in iron, calcium, zinc, selenium and manganese. In addition, mixing dry fruits with some fresh fruits would help in getting vitamin C which in turn facilitates complete absorption of iron inside the stomach.

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Textbook of Nutrition and Dietetics for BSc Nursing Students

Medicinal Value of Vegetable Like fruits, vegetables are also low in calories and fats but contain good amounts of vitamins and minerals. All green, yellow, orange vegetables are rich source of calcium, magnesium, potassium, iron, beta carotene, vitamin B complex, vitamin C, vitamin A and vitamin K. • •

Vegetables too have antioxidant property which help stay away from stress, diseases and cancers and develop capacity to fight against diseases. Vegetables are packed with dietary fibers such as cellulose, mucilage, hemicelluloses gums, pectin etc., which retain good amount of moisture in fecal matter and help its smooth passage out of body and prevent chronic constipation, hemorrhoids, colon cancer, irritable bowel syndrome and rectal fissures.

Cereals and its Medicinal Values Cereals have stored the elements for the germination and growth such as starch, fat, protein, organic mineral salts and vitamins. Cereals constituted the most important article of human food. Cereals are the cheapest and widely available sources of energy. Cellulose, hemicelluloses present in cereal help to improve peristalsis in the intestine and bulk to the stools. • • •

• • •

Cereals contain proteins like albumins, globulins, glutamines, etc. Cereals when consumed with pulses, improve the quality of protein. This protein is required to sustain growth and repair of body tissue. Cereals promote age reversal by virtue of their supply of vitamins B and E. These are helpful in providing good protection against heart disease. These are also potent sources of minerals especially calcium, phosphorous, magnesium, iron and zinc. High phosphorous is an important component of brain tissues. Generally, fruits and vegetables are poor sources of phosphorous and cereals supplement this deficiency. Brown rice supplies potassium which is needed for maintaining water balance and keeping blood pressure down. Oats contain rich soluble fibers and is digested slowly and releases slowly the glucose in the intestines for absorption. So it is prescribed in diabetic diets to prevent and control diabetes mellitus. Ragi preparation foods are good to eat in case of iron deficiency anemia.

Medicinal Value of Spices and Condiments Daily use of spices and condiments in Indian diet is very common for their rich flavor and their healing power. Their benefits are many, be it for spiritual reasons or to spice up our taste buds, or as a home remedy for ailments like cold, or sore throat, etc. •

• • • •

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Essential oils in them have been found to have anti-inflammatory function, preparing them for symptomatic relief in inflammatory health problems such as rheumatoid arthritis, osteoarthritis and ulcerative colitis. Many unique compounds in them can reduce blood sugar levels in diabetes. Garlic has certain compounds which help in reduction of cholesterol and blood pressure and help in cutting down coronary artery disease and stroke risk. Daily use of onion prevents heart attack. Ginger reduces pain and swelling in people with arthritis. It also works against migraines by blocking inflammatory substances called prostaglandin. It also plays a role in preventing and slowing down the growth of cancer.

•

Turmeric is also a potentially powerful cancer fighter. Research suggests that it may protect against colon cancer as well as melanoma, the deadliest form of skin cancer. Cinnamon has become most famous for its ability to improve blood sugar control in people with diabetes. Cinnamon can even help prevent blood clot, making it especially heart smart.

Medicinal Value of Curd or Yogurt Curd is taken in various forms throughout the world, as it has several benefits. No meal in India is complete without curd or buttermilk. It contains probiotic or friendly bacteria that thrive in our intestine and protect us against intestinal infections. It also increases digestibility.

Medicinal Value of Green Tea Green tea protects us from digestive and respiratory tract infections. It is also believed to have anticarcinogenic properties and prevents against colon and stomach cancers.

Chapter 1  Introduction to Nutrition

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NUTRIENTS CLASSIFICATION OF NUTRIENTS A nutrient is anything that nourishes a living being. We humans get our nutrients from what we eat, plants get it from the soil. It is important for our health to get the proper nutrients. Food pyramid shows the food items in a balanced amount for healthy diet (Fig. 1.1). Different foods contain different nutrients. They give us energy to perform daily functions, as well as fuel to build tissues and grow. These nutrients are broken up into two distinct categories. • •

Macronutrients Micronutrients

Fig. 1.1  Food pyramid

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Textbook of Nutrition and Dietetics for BSc Nursing Students

MACRONUTRIENTS AND MICRONUTRIENTS Macronutrients Macronutrients are substances that provide calories which are metabolized for energy. They are called macronutrients because human needs them in large amount. Macronutrients are vital for every function we perform in the body because they serve as fuel for the body. Main three macronutrients with their own caloric value are as follows: • • •

Carbohydrates = 4 kcal/g Fats = 9 kcal/g Proteins = 4 kcal/g

Carbohydrates Carbohydrates are the major source of energy. About 50–70% of energy value in the average diet is provided by carbohydrates. They are easily converted into fuel. Digestive system changes carbohydrates into glucose. Body uses this glucose for energy for cells, tissues and organs. Caloric Value of Carbohydrates

Humans need a minimum intake of food energy to sustain their metabolism and to drive their muscles. In our country, 60–80% of a day’s energy needs are met from carbohydrates in the form of starch derived from cereals and pulses. Calories are needed to provide energy for the functioning of the body. The number of calories in a food depends on the amount of energy the food provides. The number of calories a person needs depends upon his age, height, weight, gender and activity level. Foods are composed of mainly carbohydrates, fats, proteins, water, vitamins and minerals. Carbohydrates, fats, proteins and water represent all weight of food but vitamins and minerals make up only small percent of weight. These elements are produced different quantities of energy when burnt. The amount of energy produced when one gram of any of these elements is burnt is known as its calorific value. The caloric value of carbohydrate is 4 calories. Recommended Daily Allowances (RDA)

It is the amount of nutrient and calorie intake per day considered necessary for maintenance of good health, calculated for males and females of various ages and recommended by the food and nutrition board of National Research Council. Children and adults should consume 45–65% of their calorie intake as carbohydrates and at least 130 g of carbohydrates per day. To find out number of grams of carbohydrates needed each day calculate 45–65% of your total calorie intake and dividing by 4. For example, if we eat 2,000 calorie diet then the amount of carbohydrate is 225–325 g/day. Dietary Sources

The important sources of carbohydrates in the children and adults are cereals, millets, roots, tubers, pulses, sugar and jaggery. Milk and sugar are important sources in the diets of infants. Proteins

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They are one of the building blocks of body tissues and can also serve as a fuel source. Proteins are required for growth in children and maintenance of body weight in adults. Protein constitutes about 20% of the body weight. Protein can be found in all cells of body by mainly in muscles. Food rich in protein includes meat, poultry, fish, nuts, egg, milk and milk products. Proteins are made up of simpler chemical substances known as amino acids. The nutrient value of protein depends on their amino acid contents.

Calories are needed to provide energy to body for proper functioning. The number of calories in a food depends on the amount of the energy the food provides. One gram of protein gives 4 kcal. The recommended daily allowances for protein are given in Table 1.1. Dietary Sources

Animal products are rich sources of proteins. Animal protein has a balanced combination of all the amino acid, hence it is called as complete protein. On the other hand, plant protein is incomplete except soybean protein. So a vegetarian person requires a variety in plant protein sources for proper development. Incomplete protein is deficient in one or more of the essential amino acids. Animal sources

Meat, egg, milk, cheese, fish, egg proteins are considered to be the best among food proteins because of their high biological value and digestibility. Vegetable sources

Chapter 1  Introduction to Nutrition

Caloric Value of Proteins

It includes pulses, beans, cereals, nuts and oilseeds. In developing countries like India, cereals and pulses are the main sources of dietary protein because they are cheap, easily available and consumed in bulk. TABLE 1.1: Recommended dietary allowances for protein Group

Particulars

Protein (day)

Man

Sedentary work Moderate work Heavy work

60

Woman

Sedentary work Moderate work Heavy work Pregnant woman Lactating woman 0–6 months 6–12 months

50

Infants

0–6 months 6-12 months

2.05 kg 1.65 kg

Children

1–3 years 4–6 years 7–9 years

22 30 41

Boys

10–12 years

54

Girls

10–12 years

57

Boys

13–15 years

70

Girls

13–15 years

65

Boys

16–18 years

78

Girls

16–18 years

63

50 + 15 50 + 25 50 + 18

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Textbook of Nutrition and Dietetics for BSc Nursing Students

Fats Fat is a major nutritional element and a vital aspect of healthy diet. Fat helps to maintain body temperature. Fat cushions organs which protects them from trauma. Excessive fats lead to obesity. A molecule of dietary fat typically consists of several fatty acids. Fats may be classified as saturated or unsaturated depending on the structure of fatty acid involved.

Micronutrients These are essential dietary elements that are needed only in very small quantities. Micronutrients are also known as trace elements. This group includes vitamins and minerals (Fig. 1.2). Vitamins Vitamins are micronutrients as they are required in small amount. Vitamins are organic compounds occurring in small quantities in different natural foods and necessary for the growth and maintenance of good health in human beings. Many of them cannot be synthesized, at least inadequate amounts, by the body and must be obtained from the diet. So far, about 15 different vitamins have been isolated in a pure state from natural foods. Vitamins may be classified broadly into two groups as given in Table 1.2. • •

Fat-soluble vitamins Water-soluble vitamins

Minerals

Fig. 1.2  Sources of micronutrients

TABLE 1.2: Classification of vitamins Fat-soluble vitamins

Water-soluble vitamins

• Vitamins A (Retinol) and carotenes. • Vitamin D ƒ (D2 - Calciferol) ƒ (D3 Cholecalciferol) • Vitamin E (Tocopherol) • Vitamin K (Quinones) (K1-K2)

• Vitamin B (Thiamine)

1 Mineral elements are chemical substances found in • Vitamin B2 (Riboflavin) body tissues and fluids. They occur in foods as salts. • Vitamin B6 (Pyridoxine) The  body contains about 24 minerals, all of which • Vitamin B12 (Cyanocobalamin) must be provided by the diet. Broadly the two kinds of ƒ Folic acid minerals are: macrominerals and trace minerals. ƒ Biotin The microminerals consist of calcium, phosphorus, ƒ Choline manganese, sodium, potassium, chloride and sulfur. ƒ Vitamin B12 The trace means in little quantity but even body • Vitamin C (Ascorbic acid) needs them equally. Trace minerals include iron, manganese, copper, iodine, zinc, cobalt, fluoride and selenium. All have different functions in our body like calcium is required for bones and teeth. Phosphorus is the constituent of body cells of soft tissues such as muscles, liver, etc. Iron and copper help in formation of hemoglobin. Zinc is a constituent of an enzyme. The recommended dietary allowance for minerals is given in Table 1.3.

Functions of Minerals

The functions of minerals are following: •

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• •

Minerals play a main role in the maintenance of osmotic pressure, and thus regulate the exchange of water and solutes within the animal body. Minerals are essential constituents of skeletal structures such as bones and teeth. Minerals serve as structural constituents of soft tissues.

Minerals

Recommended daily intake

Calcium

1,000 mg

Chlorine

3,400 mg

Chromium

120 g

Copper

2 mg

Fluorine

3.5 mg

Iodine

150 mcg

Iron

15 mg

Manganese

5 mg

Magnesium

350 mg

Molybdenum

5 mg

Nickel