Nutrition: Concepts & Controversies
Frances Sienkiewicz Sizer and Ellie Whitney
Contents
Preface xiv
Chapter 1
Food Choices and Human
Health 2
A Lifetime of Nourishment 3
The Diet–Health Connection 4
Other Lifestyle Choices 4
Genetics, Nutrition, and
Individuality 5
Think Fitness: Why Be Physically Active? 5
The Human Body and Its Food 6
Meet the Nutrients 6
Can I Live on Just Supplements? 8
The Challenge of Choosing Foods 9
An Abundance of Foods 9
How, Exactly, Can I Recognize a
Nutritious Diet? 10
Why People Choose Foods 12
The Science of Nutrition 13
The Scientific Approach 13
Scientific Challenge 14
Can I Trust the Media for Nutrition
Information? 16
National Nutrition Research 17
Healthy People Objectives for the Nation 17
Changing Behaviors 17
The Process of Change 18
Taking Stock and Setting Goals 18
Start Now 18
A Consumer’s Guide to: Reading
Nutrition News 19
Food Feature: Nutrient Density: How to
Get Enough Nutrients without Too Many
Calories 20
Self Check 21
Controversy 1: Sorting Impostors from Real Nutrition
Experts 23
Chapter 2
Nutrition Tools—Standards and
Guidelines 30
Nutrient Recommendations 31
Two Sets of Standards 31
The DRI Lists and Purposes 32
Understanding the DRI 34
How the Committee Establishes DRI Values—
An RDA Example 35
Determining Individual Requirements 35
Setting Energy Requirements 36
Why Are Daily Values Used on Labels? 36
Dietary Guidelines for Americans 36
Think Fitness: Recommendations for Daily Physical
Activity 39
Diet Planning Using the USDA
Dietary Patterns 40
The Food Groups and Subgroups 40
Choosing Nutrient-Dense Foods 43
Diet Planning in Action 44
MyPlate Educational Tool 46
Flexibility of the USDA Dietary Patterns 46
Food Lists for Weight Management 47
The Last Word on Diet Planning 48
A Consumer’s Guide to: Controlling Portion Sizes at
Home and Away 49
Checking Out Food Labels 51
What Food Labels Must Include 51
What Food Labels May Include 53
Food Feature: Getting a Feel for the Nutrients
in Foods 56
Self Check 59
Controversy 2: Are Some Foods “Superfoods” for
Health? 61
Chapter 3
The Remarkable Body 66
The Body’s Cells 67
Genes Control Functions 67
Cells, Tissues, Organs, and Systems 68
The Body Fluids and the Circulatory System 69
The Hormonal and Nervous Systems 72
What Do Hormones Have to Do with Nutrition? 72
How Does the Nervous System Interact
with Nutrition? 73
The Digestive System 75
Why Do People Like Sugar, Salt, and Fat? 75
The Digestive Tract Structures 76
The Mechanical Aspect of Digestion 76
The Chemical Aspect of Digestion 79
Microbes in the Digestive Tract 80
Are Some Food Combinations More Easily
Digested than Others? 81
If “I Am What I Eat,” Then How Does a Peanut
Butter Sandwich Become “Me”? 82
Absorption and Transport of Nutrients 83
A Letter from Your Digestive
Tract 85
The Excretory System 89
Storage Systems 90
When I Eat More than My Body
Needs, What Happens to the Extra
Nutrients? 90
Variations in Nutrient Stores 91
Conclusion 91
Self Check 92
Controversy 3:
Alcohol 93
Chapter 4
The Carbohydrates: Sugar,
Starch, Glycogen, and Fiber 102
A Close Look at Carbohydrates 103
Sugars 104
Starch 105
Glycogen 106
Fibers 107
Summary 107
The Need for Carbohydrates 107
If I Want to Lose Weight and Stay Healthy, Should I Avoid
Carbohydrates? 108
Why Do Nutrition Experts Recommend
Fiber-Rich Foods? 109
Fiber Intakes and Excesses 113
Whole Grains 114
From Carbohydrates to Glucose 117
Digestion and Absorption of Carbohydrates 117
A Consumer’s Guide to: Finding Whole-Grain
Foods 118
Why Do Some People Have Trouble Digesting Milk? 122
The Body’s Use of Glucose 122
Splitting Glucose for Energy 123
How Is Glucose Regulated in the Body? 124
Excess Glucose and Gain of Body Fat 126
Think Fitness: What Can I Eat to Make Workouts
Easier? 127
The Glycemic Response 128
What Happens If Blood Glucose
Regulation Fails? 129
Diabetes 129
Hypoglycemia 129
Conclusion 130
Food Feature: Finding the
Carbohydrates in Foods 130
Self Check 135
Controversy 4: Are Added Sugars “Bad”
for You? 136
Chapter 5
The Lipids: Fats,
Oils, Phospholipids,
and Sterols 140
Introducing the Lipids 141
How Are Fats Useful to the Body? 141
How Are Fats Useful in Food? 143
A Close Look at Lipids 144
Triglycerides: Fatty Acids and Glycerol 144
Saturated vs. Unsaturated Fatty Acids 145
Phospholipids and Sterols 147
Lipids in the Body 148
How Are Fats Digested and Absorbed? 148
How Does Fat Travel Around the Body? 149
Storing and Using the Body’s Fat 150
Dietary Fat, Cholesterol, and Health 152
Recommendations for Lipid Intakes 152
Lipoproteins and Heart Disease Risk 154
What Does Food Cholesterol Have to Do
with Blood Cholesterol? 155
Recommendations Applied 156
Think Fitness: Why Exercise the Body for the
Health of the Heart? 156
Essential Polyunsaturated Fatty Acids 157
Why Do I Need Essential Fatty Acids? 157
Omega-6 and Omega-3 Fatty Acid Families 158
Omega-3 Fatty Acids 158
Requirements and Sources 159
A Consumer’s Guide to: Weighing Seafood’s Risks
and Benefits 160
The Effects of Processing on Unsaturated Fats 161
What Is “Hydrogenated Vegetable Oil,” and What’s
It Doing in My Chocolate Chip Cookies? 161
What Are Trans-Fatty Acids, and Are They Harmful? 162
Fat in the Diet 163
Get to Know the Fats in Foods 163
Fats in Protein Foods 164
Dairy Products 165
Grains 166
Food Feature: Defensive
Dining 167
Self Check 172
Controversy 5: The Lipid Guidelines
Debate 174
Chapter 6
The Proteins and
Amino Acids 178
The Structure of Proteins 179
Amino Acids 179
How Do Amino Acids Build Proteins? 181
The Variety of Proteins 182
Think Fitness: Can Eating Extra Protein Make
Muscles Grow Stronger? 184
Denaturation of Proteins 186
Digestion and Absorption of Dietary Protein 186
Protein Digestion 186
What Happens to Amino Acids
after Protein Is Digested? 187
The Importance of Protein 187
The Roles of Body Proteins 189
Providing Energy and Glucose 192
The Fate of an Amino Acid 193
A Consumer’s Guide to: Evaluating Protein and
Amino Acid Supplements 194
Food Protein: Need and Quality 196
How Much Protein Do People Need? 196
Nitrogen Balance 196
Protein Quality 198
Protein Deficiency and Excess 200
What Happens When People Consume
Too Little Protein? 200
Is It Possible to Consume Too Much Protein? 201
Is a Gluten-Free Diet Best for Health? 202
Food Feature: Getting Enough but Not Too Much
Protein 203
Self Check 205
Controversy 6: Are Plant-Based
or Meat-Based Diets Better for
Health? 207
Chapter 7
The Vitamins 214
Definition and Classification
of Vitamins 215
Vitamin Precursors 216
Two Classes of Vitamins: Fat-Soluble and Water-
Soluble 216
The Fat-Soluble Vitamins 216
Vitamin A 217
What Are the Roles of Vitamin A? 218
Vitamin A Deficiency Around the World 219
Can Vitamin A Cause Toxicity? 220
Vitamin A Recommendations and Sources 220
Beta-Carotene 221
Vitamin D 223
What Are the Roles of Vitamin D? 223
Too Little Vitamin D—A Danger to Bones 224
Too Much Vitamin D—A Danger to Soft Tissues 225
Is Vitamin D Really the Sunshine Vitamin? 226
Vitamin D Intake Recommendations 227
Which Foods Supply Vitamin D? 227
Vitamin E 228
Vitamin K 230
Roles, Deficiency, and Toxicity of Vitamin K 230
Vitamin K Requirements and Food Sources 231
The Water-Soluble Vitamins 231
Vitamin C 232
Think Fitness: Vitamins for Athletes 233
What Are the Roles of Vitamin C in the Body? 233
Deficiency Symptoms and Intakes 235
Can Vitamin C Cause Toxicity? 235
Vitamin C Recommendations 235
Which Foods Supply Vitamin C? 236
The B Vitamins in Unison 236
What Are the Roles of B Vitamins in
Metabolism? 236
B Vitamin Deficiencies 237
The B Vitamins as
Individuals 239
Thiamin 239
A Consumer’s Guide to: The Effects of Food
Processing on Vitamins 240
Riboflavin 242
Niacin 243
Folate 243
Vitamin B12 246
Vitamin B6 247
Biotin and Pantothenic Acid 249
Choline 249
Nonvitamins 250
Food Feature: Choosing Foods Rich in
Vitamins 255
Self Check 258
Controversy 7: Vitamin Supplements: What Are the
Benefits and Risks? 260
Chapter 8
Water and Minerals 266
Water 268
Why Is Water the Most Indispensable Nutrient? 269
The Body’s Water Balance 270
Quenching Thirst and Balancing Losses 270
How Much Water Do I Need to Drink in a Day? 271
A Consumer’s Guide to: Liquid Calories 273
Body Fluids and Minerals 275
Water Follows Salt 275
Fluid and Electrolyte Balance 276
Acid–Base Balance 276
The Major Minerals 277
Calcium 277
Phosphorus 281
Magnesium 281
Sodium 283
Potassium 287
Chloride 288
Sulfate 288
The Trace Minerals 289
Iodine 289
Iron 290
Think Fitness: Exercise-Deficiency
Fatigue 292
Zinc 295
Selenium 297
Fluoride 297
Chromium 298
Copper 299
Other Trace Minerals and Some Candidates 299
Food Feature: Meeting the Need
for Calcium 302
Self Check 305
Controversy 8: Osteoporosis: Can Lifestyle Choices
Reduce the Risk? 306
Chapter 9
Energy Balance and Healthy
Body Weight 312
The Problems of Too Little
or Too Much Body Fat 313
What Are the Risks from
Underweight? 314
What Are the Risks from Too Much
Body Fat? 314
What Are the Risks from Central
Obesity? 315
How Fat Is Too Fat? 316
The Body’s Energy Balance 318
Energy in and Energy Out 318
How Many Calories Do I Need
Each Day? 318
Estimated Energy Requirements (EER) 320
How Can I Calculate My EER Range? 320
Body Weight vs. Body Composition 321
Using the Body Mass Index (BMI) 321
Measuring Body Composition and
Fat Distribution 322
How Much Body Fat Is Ideal? 323
The Appetite and
Its Regulation 323
Hunger and Appetite—“Go” Signals 324
Satiation and Satiety—“Stop” Signals 325
Inside-the-Body Theories
of Obesity 327
Outside-the-Body Theories
of Obesity 328
Think Fitness: Activity for a Healthy Body
Weight 329
How the Body Loses
and Gains Weight 331
The Body’s Response to Energy Deficit 332
The Body’s Response to Energy Surplus 334
Achieving and Maintaining
a Healthy Body Weight 335
A Consumer’s Guide to: Fad Diets 337
What Food Strategies Are Best for
Weight Loss? 339
Physical Activity Strategies 342
What Strategies Are Best for
Weight Gain? 343
Medical Treatment of Obesity 344
Obesity Medications 344
Obesity Surgery 344
Dietary Supplements and Gimmicks 345
Once I’ve Changed My Weight,
How Can I Stay Changed? 346
Conclusion 347
Food Feature: Behavior Change Methods for
Weight Management 348
Self Check 351
Controversy 9: The Perils of Eating
Disorders 352
Chapter 10
Performance
Nutrition 360
The Benefits of Fitness 361
The Nature of Fitness 361
Physical Activity Guidelines 362
The Essentials of Fitness 364
How Do Muscles Adapt to Physical Activity? 364
How Does Aerobic Training Benefit the Heart? 366
Think Fitness: Exercise Safety 367
Three Energy Systems 367
The Muscles’ Energy Reservoir 367
The Anaerobic Energy System 369
The Aerobic Energy System 370
The Active Body’s Use of Fuels 370
The Need for Food Energy 370
Carbohydrate: Vital for Exercisers 371
Carbohydrate Recommendations for Athletes 374
Fat as Fuel for Physical Activity 375
Fat Recommendations for Athletes 376
Protein for Building Muscles and for Fuel 377
Protein Recommendations for Athletes 378
Vitamins and Minerals—
Keys to Performance 378
Do Athletes Need Nutrient Supplements? 379
Iron—A Mineral of Concern 379
Fluids and Temperature Regulation in Physical
Activity 380
Water Losses during Physical Activity 380
Fluid and Electrolyte Needs during Physical Activity 382
Other Beverages 383
A Consumer’s Guide to: Selecting Sports
Drinks 384
Putting It All Together 385
Food Feature: Choosing a Performance Diet 387
Self Check 391
Controversy 10: Ergogenic Aids: Breakthroughs,
Gimmicks, or Dangers? 392
Chapter 11
Nutrition and Chronic
Diseases 396
Causation of Chronic Diseases 398
Cardiovascular Diseases (CVD) 399
Atherosclerosis and Hypertension 400
Risk Factors for Cardiovascular Disease 402
Preventive Measures against CVD 405
Think Fitness: Ways to Include Physical Activity in
a Day 406
A Consumer’s Guide to: Nutrition and the Immune
System 410
Diabetes 412
How Does Type 2 Diabetes Develop? 413
Harms from Diabetes 413
Diabetes Prevention and Management 415
Cancer 417
The Cancer Disease Process 417
Cancer Risk Factors 418
Cancer Prevention 420
Conclusion 422
Food Feature: The DASH Diet: Preventive
Medicine 422
Self Check 425
Controversy 11: Nutrient–Drug Interactions: Who Should
Be Concerned? 426
Chapter 12
Food and Water Safety and
Food Technology 432
Microbes and Food Safety 434
How Do Microbes in Food Cause Illness in the Body? 434
Food Safety from Farm to Plate 436
Safe Food Practices for Individuals 439
Which Foods Are Most Likely to Cause Illness? 442
Protein Foods 443
Raw Produce 445
Other Foods 446
Advances in Microbial Food Safety 448
Is Irradiation Safe? 448
Modified Atmosphere Packaging 449
Toxins, Residues, and Contaminants in Foods 449
Natural Toxins in Foods 449
Pesticides 450
Animal Drugs—What Are the Risks? 452
A Consumer’s Guide to: Understanding Organic
Foods 453
Environmental Contaminants 455
Water Safety and Sources 457
Drinking Water 457
Is Tap Water Safe to Drink? 458
Is Bottled Water Safest? 458
Are Food Additives Safe? 458
Regulations Governing Additives 458
Additives to Improve Safety and Quality 460
Flavoring Agents 460
Fat Replacers and Artificial Fats 463
Incidental Food Additives 463
Conclusion 464
Food Feature: Handling Real-Life Challenges
to Food Safety 464
Self Check 467
Controversy 12: Bioengineered Foods: What Are the
Pros and Cons? 469
Chapter 13
Life Cycle Nutrition: Mother
and Infant 476
Pregnancy: The Impact
of Nutrition on the Future 477
Preparing for Pregnancy 477
The Events of Pregnancy 480
Increased Needs for Nutrients 481
Food Assistance Programs 486
How Much Weight Gain Is Ideal during Pregnancy? 486
Weight Loss after Pregnancy 487
Should Pregnant Women Be Physically Active? 488
Teen Pregnancy 488
Think Fitness: Physical Activities for Pregnant
Women 489
Why Do Some Women Crave Pickles and Ice Cream While
Others Can’t Keep Anything Down? 489
Some Cautions for Pregnant Women 490
Drinking during Pregnancy 492
Alcohol’s Effects 492
Fetal Alcohol Syndrome 493
Experts’ Advice 493
Troubleshooting 494
Diabetes 494
Hypertension 495
Preeclampsia 495
Lactation 495
Nutrition during Lactation 496
When Should a Woman Not Breastfeed? 497
Feeding the Infant 498
Nutrient Needs 498
Why Is Breast Milk So Good for Babies? 500
Formula Feeding 503
A Consumer’s Guide to: Formula Advertising versus
Breastfeeding Advocacy 504
An Infant’s First Solid Foods 505
Looking Ahead 509
Food Feature: Mealtimes with Infants 510
Self Check 511
Controversy 13: How Do Today’s Food Choices Affect
Future Generations? 512
Chapter 14
Child, Teen, and
Older Adult 516
Early and Middle Childhood 518
Feeding a Healthy Young Child 518
Mealtimes and Snacking 522
How Do Nutrient Deficiencies
Affect a Child’s Brain? 525
The Problem of Lead 526
Food Allergies, Intolerances, and
Aversions 528
Can Diet Make a Child
Hyperactive? 530
Dental Caries 531
Is Breakfast Really the Most Important
Meal of the Day for Children? 532
How Nourishing Are the Meals Served at School? 533
Nutrition in Adolescence 534
Nutrient Needs 535
Menstruation and Acne 536
A Consumer’s Guide to: Acne and Diet 537
Dietary Patterns and Nutrient Intakes 538
The Later Years 539
Nutrition in the Later Years 540
Energy, Activity, and the Muscles 540
Protein Needs 541
Think Fitness: Physical Activity for the Older
Adult 542
Carbohydrates and Fiber 542
Fats and Arthritis 543
Vitamin Needs 543
Water and the Minerals 544
Can Diet Choices Lengthen Life? 545
Aging and Inflammation 547
Can Diet Affect the Course of Alzheimer’s Disease? 548
Food Choices of Older Adults 548
Food Feature: Single Survival and Nutrition
on the Run 550
Self Check 552
Controversy 14: Childhood Obesity and Early Chronic
Diseases 554
Chapter 15
Hunger and the Future of
Food 562
U.S. Food Insecurity 563
Food Poverty in the United States 564
What U.S. Food Programs Address
Low Food Security? 566
World Poverty and Hunger 567
The Malnutrition of Extreme
Poverty 569
Hidden Hunger—Vitamin and Mineral
Deficiencies 569
Consequences of Childhood Malnutrition 570
Medical Nutrition Therapy 571
The Future Food Supply
and the Environment 571
Threats to the Food Supply 572
Food Loss and Food Waste 573
How Can People Help? 575
Government Action 575
Private and Community Enterprises 576
Educators and Students 576
Food and Nutrition Professionals 576
Individuals 576
Conclusion 576
A Consumer’s Guide to: Making “Green” Choices
(Without Getting “Greenwashed”) 577
Self Check 579
Controversy 15: How Can We Feed Ourselves
Sustainably? 580
Appendixes
A Chemical Structures: Carbohydrates,
Lipids, and Amino Acids A-3
B World Health Organization
Guidelines B-1
C Aids to Calculations C-1
D Choose Your Foods: Food Lists for
Diabetes and Weight Management D-1
E Dietary Patterns to Meet the Dietary
Guidelines for Americans E-1
F Notes F-1
G Answers to Chapter Questions G-1
H Physical Activity Levels and Energy
Requirements H-1
Glossary GL-1
Index IN-1
Dietary Reference Intakes (DRI)
(at the back of the book)
Estimated Energy Requirements (EER),
Recommended Dietary Allowances (RDA),
and Adequate Intakes (AI) for Water,
Energy, and the Energy Nutrients
Recommended Dietary Allowances (RDA)
and Adequate Intakes (AI) for Vitamins
Recommended Dietary Allowances (RDA)
and Adequate Intakes (AI) for Minerals
Tolerable Upper Intake Levels (UL) for
Vitamins
Tolerable Upper Intake Levels (UL) for
Minerals and Chronic Disease Risk
Reduction Intakes (CDRR) for Sodium
Daily Values (DV) for Food Labels
Glossary of Nutrient Measures
Body Mass Index (BMI)
Body Mass Index-for-Age Percentiles:
Boys and Girls, Age 2 to 20