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Nutrition. Chapter 8. Nutritional Requirements: Components of a Healthy Diet. Essential nutrients = substances the body must get from food because it cannot manufacture them at all or fast enough to meet its needs Proteins Carbohydrates Fats Vitamins Minerals Water. Energy from Food.

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Chapter 8

Nutritional requirements components of a healthy diet
Nutritional Requirements: Components of a Healthy Diet

  • Essential nutrients = substances the body must get from food because it cannot manufacture them at all or fast enough to meet its needs

    • Proteins

    • Carbohydrates

    • Fats

    • Vitamins

    • Minerals

    • Water

Energy from food
Energy from Food

  • Three classes of essential nutrients supply energy

  • Kilocalorie = a measure of energy content in food; the amount of heat it takes to raise the temperature of 1 liter of water 1°C; commonly referred to as “calorie”

Proteins the basis of body structure
Proteins—The Basis of Body Structure

  • Protein = a compound made of amino acids that contains carbon, hydrogen, oxygen, and nitrogen

  • Of twenty common amino acids in foods, nine are essential

  • Proteins form key parts of the body’s main structural components—muscles and bones—and of blood, enzymes, cell membranes, and some hormones

Complete and incomplete proteins
Complete and Incomplete Proteins

  • Complete protein sources = foods that supply all the essential amino acids in adequate amounts

    • Meat, fish, poultry, eggs, milk, cheese, and soy

  • Incomplete protein sources = foods that supply most but not all essential amino acids

    • Plants, including legumes, grains, and nuts

Protein sources
Protein Sources

  • 3 ounces lean meat, poultry, or fish

  • 1/2 cup tofu

    • 20–25 grams of protein

  • 1 cup legumes

    • 15–20 grams of protein

  • 1 cup milk or yogurt or 1-1/2 ounces cheese

    • 8–12 grams of protein

  • Cereals, grains, nuts, vegetables

    • 2–4 grams of protein per serving

Recommended protein intake
Recommended Protein Intake

  • Adequate daily intake of protein = 0.8 gram per kilogram (0.36 gram per pound) of body weight

  • Acceptable Macronutrient Distribution Range = 10–35% of total daily calories as protein

Fats essential in small amounts
Fats—Essential in Small Amounts

  • Fats supply energy, insulate the body, support and cushion organs, absorb fat-soluble vitamins, add flavor and texture to foods

  • Essential fats (linoleic acid and alpha-linolenic acid) are key regulators of body process such as the maintenance of blood pressure and the progress of a healthy pregnancy

Types and sources of fats
Types and Sources of Fats

  • Saturated fat = a fat with no carbon-carbon double bonds; usually solid at room temperature

    • Found primarily in animal foods and palm and coconut oils

  • Monounsaturated fat = a fat with one carbon-carbon double bond; usually liquid at room temperature

    • Found in certain vegetables, nuts, and vegetable oils

  • Polyunsaturated fat = a fat with two or more carbon-carbon double bonds; usually liquid at room temperature

    • Found in certain vegetables, nuts, and vegetable oils and in fatty fish

Types and sources of fats1
Types and Sources of Fats

  • Two key forms of polyunsaturated fats:

    • Omega-3 fatty acids are produced when the endmost double bond of a polyunsaturated fat occurs three carbons from the end of the fatty acid chain

      • Found primarily in fish

    • Omega-6 fatty acids are produced when the endmost double bond of a polyunsaturated fat occurs six carbons from the end of the fatty acid chain

      • Found primarily in certain vegetable oils, especially corn, soybean, and cottonseed oils

Trans fatty acids
Trans Fatty Acids

  • The process of hydrogenation, in which hydrogens are added to unsaturated fats, produces a mixture of saturated fatty acids and standard and trans forms of unsaturated fatty acids

  • Trans fatty acids have an atypical shape that affects their chemical activity

Fats and health
Fats and Health

  • Fats affect blood cholesterol levels

    • Low-density lipoprotein (LDL) = “bad” cholesterol

    • High-density lipoprotein (HDL) = “good” cholesterol

    • Saturated and trans fats raise levels of LDL; trans fats also lower levels of HDL

    • Unsaturated fats lower levels of LDL

Fats and health1
Fats and Health

  • Fats also affect triglyceride levels, inflammation, heart rhythm, blood pressure, and cancer risk

  • Best choices = monounsaturated fats and polyunsaturated omega-3 fats

  • Limit intake of saturated and trans fats

Recommended fat intake
Recommended Fat Intake

  • Adequate daily intake of fat:

    = about 3–4 teaspoons of vegetable oil

  • Acceptable Macronutrient Distribution Range = 20–35% of total daily calories as fat

Carbohydrates an ideal source of energy
Carbohydrates—An Ideal Source of Energy

  • The primary function of dietary carbohydrate is to supply energy to body cells.

  • Some cells, such as those in the brain, nervous system, and blood, use only carbohydrates for fuel

  • During high-intensity exercise, muscles get most of their energy from carbohydrates

  • During digestion, carbohydrates are broken into single sugar molecules such as glucose for absorption; the liver and muscles take up glucose and store it in the form of glycogen

Simple and complex carbohydrates
Simple and Complex Carbohydrates

  • Simple carbohydrates contain one or two sugar units in each molecule

    • Found naturally in fruits and milk and added to many other foods

    • Include sucrose, fructose, maltose, and lactose

  • Complex carbohydrates consist of chains of many sugar molecules

    • Found in plants, especially grains, legumes, and tubers

    • Include starches and most types of dietary fiber

Whole grains
Whole Grains

  • Before they are processed, all grains are whole grains consisting of an inner layer of germ, a middle layer called the endosperm, and an outer layer of bran

  • During processing, the germ and bran are often removed, leaving just the starchy endosperm

  • Refined carbohydrates usually retain all the calories of a whole grain but lose many of the nutrients

Refined carbohydrates versus whole grains
Refined Carbohydrates Versus Whole Grains

  • Whole grains are higher than refined carbohydrates in fiber, vitamins, minerals, and other beneficial compounds

  • Whole grains take longer to digest

    • Make people feel full sooner

    • Cause a slower rise in glucose levels

  • Choose foods that have a whole grain as the first item on the ingredient list on the food label

    • Whole wheat, whole rye, whole oats, oatmeal, whole-grain corn, brown rice, popcorn, barley, etc.

  • Choose 3 or more servings of whole grains per day

Glycemic index
Glycemic Index

  • Consumption of carbohydrates causes insulin and glucose levels in the blood to rise and fall

  • Glycemic index = a measure of how the ingestion of a particular food affects blood glucose levels

  • Foods with a high glycemic index cause quick and dramatic changes in glucose levels

  • Diets rich in high glycemic index foods are linked to increased risk of diabetes and heart disease

Recommended carbohydrate intake
Recommended Carbohydrate Intake

  • Adequate daily intake of carbohydrate = 130 grams

  • Acceptable Macronutrient Distribution Range = 45–65% of total daily calories as carbohydrate

  • Limit on intake of added sugars

    • Food and Nutrition Board: 25% or less of total daily calories

    • WHO: 10% or less of total daily calories

    • USDA: 8 teaspoons (32 grams) or less for a 2000-calorie diet

Acceptable macronutrient distribution ranges summary
Acceptable Macronutrient Distribution Ranges: Summary

  • Protein = 10–35% of total daily calories

  • Fat = 20–35% of total daily calories

  • Carbohydrate = 45–65% of total daily calories

Fiber a closer look
Fiber—A Closer Look

  • Dietary fiber = nondigestible carbohydrates and lignin that are present naturally in plants

  • Functional fiber = nondigestible carbohydrates isolated from natural sources or synthesized in a lab and added to a food or supplement

  • Total fiber = dietary fiber + functional fiber

Types of fiber
Types of Fiber

  • Soluble (viscous) fiber = fiber that dissolves in water or is broken down by bacteria in the large intestine

    • Slows the body’s absorption of glucose

    • Binds cholesterol-containing compounds

  • Insoluble fiber = fiber that doesn’t dissolve in water

    • Makes feces bulkier and softer

    • Helps prevent constipation, hemorrhoids, and diverticulitis

Sources of fiber
Sources of Fiber

  • All plant foods contain fiber, but processing can remove it

  • Good sources of fiber:

    • Fruits (especially whole, unpeeled fruits)

    • Vegetables

    • Legumes

    • Oats (especially oat bran)

    • Whole grains and wheat bran

    • Psyllium (found in some cereals and laxatives)

Recommended intake of fiber
Recommended Intake of Fiber

  • Women = 25 grams per day

  • Men = 38 grams per day

  • Americans currently consume about half this amount

Vitamins organic micronutrients
Vitamins—Organic Micronutrients

  • Vitamins = organic (carbon-containing) substances needed in small amounts to help promote and regulate chemical reactions and processes in body cells.

  • Four vitamins are fat-soluble (A, D, E, and K)

  • Nine vitamins are water-soluble (C and the eight B-complex vitamins: thiamin, riboflavin, niacin, vitamin B-6, folate, vitamin B-12, biotin, and pantothenic acid)


  • Vitamins are abundant in fruits, vegetables, and grains; they are also added to some processed foods

  • If you consume too much or too little of a particular vitamin, characteristic symptoms of excess or deficiency can develop

  • Vitamins commonly lacking in the American diet:

    • Vitamin A

    • Vitamin C

    • Vitamin D

    • Vitamin E

Minerals inorganic micronutrients
Minerals—Inorganic Micronutrients

  • Minerals = inorganic (non-carbon-containing) compounds needed in small amounts for regulation, growth, and maintenance of body tissues and functions

  • There are about 17 essential minerals:

    • Major minerals (those that the body needs in amounts exceeding 100 mg per day) include calcium, phosphorus, magnesium, sodium, potassium, and chloride

    • Essential trace minerals include copper, fluoride, iodide, iron, selenium, and zinc


  • If you consume too much or too little of a particular mineral, characteristic symptoms of excess or deficiency can develop

  • Minerals commonly lacking in the American diet:

    • Iron = low intake can cause anemia

    • Calcium = low intake linked to osteoporosis

    • Potassium = low intake linked to elevated blood pressure and bone mineral loss

Osteoporosis thinning of bones

Dietary factors that build bone mass:


Vitamin D

Vitamin K

Other possible dietary factors: vitamin C, magnesium, potassium, manganese, zinc, copper, boron

Weight-bearing exercise and strength training also build and maintain bone mass

Dietary factors linked to loss of bone mass:






Protein (if intake of calcium and vitamin D is low)

Osteoporosis—Thinning of Bones

Water a vital component
Water—A Vital Component

  • Human body is composed of about 60% water; you can live only a few days without water

  • Foods and fluids you consume provide 80–90% of your daily water intake

  • Adequate intake to maintain hydration:

    • Women need to drink about 9 cups of fluid per day

    • Men need to drink about 13 cups of fluid per day

  • Drink in response to thirst; consume additional fluids for heavy exercise

Other substances in food antioxidants
Other Substances in Food: Antioxidants

  • Antioxidant = a substance that protects against the breakdown of body constituents by free radicals; actions include binding oxygen, donating electrons to free radicals, and repairing damage to molecules

    • Free radical = a chemically unstable, electron-seeking compound that can damage cell membranes and mutate genes in its search for electrons

  • Many fruits and vegetables are rich in antioxidants such as vitamin C, vitamin E, selenium, and carotenoids

Other substances in food phytochemicals
Other Substances in Food: Phytochemicals

  • Phytochemical = a naturally occurring substance found in plant foods that may help prevent and treat chronic diseases

  • Examples:

    • Certain proteins in soy foods

    • Sulforaphane in cruciferous vegetables (cabbage, broccoli, brussels sprouts, kale, cauliflower)

    • Allyl sulfides in garlic and onions

  • Fruits and vegetables are rich in phytochemicals

Nutritional guidelines planning your diet
Nutritional Guidelines: Planning Your Diet

  • Dietary Reference Intakes (DRIs) = standards for levels of nutrient intake to prevent nutrient deficiencies and reduce the risk of chronic disease

  • Dietary Guidelines for Americans = general principles of good nutrition intended to help prevent certain diet-related diseases

  • MyPyramid = a food guidance system that provides practical advice to ensure a balanced intake of essential nutrients

Dietary reference intakes dris
Dietary Reference Intakes (DRIs)

  • Set by the Food and Nutrition Board of the National Academies

  • Recommended Dietary Allowance (RDA) or Adequate Intake (AI) = recommended intake

  • Tolerable Upper Intake Level (UL) = maximum daily intake unlikely to cause health problems

  • Example of calcium recommendations for an 18-year-old woman:

    • RDA = 1300 mg/day

    • UL = 2500 mg/day

Should you take supplements
Should You Take Supplements?

  • The Food and Nutrition Board recommends supplements only for certain groups:

    • Folic acid for women capable of becoming pregnant (400 µg/day)

    • Vitamin B-12 for people over age 50 (2.4 mg/day)

  • Other possible situations for supplements:

    • Vitamin C for smokers

    • Iron for menstruating women

    • Vitamin D for older adults, people with dark skin, and people exposed to little sunlight

    • Vitamin K for newborns

    • People with certain special health concerns

Daily values
Daily Values

  • Daily Values = a simplified version of the RDAs used on food labels

  • Also included in Daily Values are standards for nutrients with no established RDA

  • Shown on food labels in terms of a 2000-calorie diet

Dietary guidelines for americans
Dietary Guidelines for Americans

  • Consume a variety of nutrient-dense foods within and among the basic food groups, while staying within energy needs

  • Most Americans need to make the following general dietary changes:

    • Eat more dark green vegetables, orange vegetables, legumes, fruits, whole grains, and low-fat and fat-free milk and milk products

    • Eat less refined grains, saturated fat, trans fat, cholesterol, added sugars, and calories

Dietary guidelines for americans1
Dietary Guidelines for Americans

  • Control calorie intake to manage body weight

    • Evaluate body weight in terms of BMI

    • Make appropriate adjustments in calorie intake and activity levels

    • For most adults, a reduction of 50–100 calories per day can prevent gradual weight gain over time

Dietary guidelines for americans2
Dietary Guidelines for Americans

  • Be physically active every day

    • To reduce the risk of chronic disease, 30 minutes per day of moderate activity

    • To prevent gradual weight gain, 60 minutes per day of moderate activity

    • To sustain weight loss, 60–90 minutes per day of moderate activity

Dietary guidelines for americans3
Dietary Guidelines for Americans

  • Increase daily intake of foods from certain groups:

    • Fruits and vegetables, especially dark green vegetables, orange vegetables, and legumes

    • Whole grains—half of all daily grain servings (3 or more servings per day)

    • Fat-free or low-fat milk and milk products

Dietary guidelines for americans4
Dietary Guidelines for Americans

  • Choose fats wisely for good health, limiting intake of saturated and trans fats

    • Total fat: 20–35% of total daily calories

    • Saturated fat: Less than 10% of total daily calories

    • Trans fat: As little as possible

    • Cholesterol: Less than 300 mg per day

Dietary guidelines for americans5
Dietary Guidelines for Americans

  • Choose carbohydrates wisely for good health, limiting intake of added sugars

    • Cut back on soft drinks, candies, sweet desserts, fruit drinks, and other sweetened foods

Leading sources of calories in the american diet
Leading Sources of Calories in the American Diet

1. Regular soft drinks (7.1% of total calories)

2. Cake, sweet rolls, doughnuts, pastries (3.6%)

3. Hamburgers, cheeseburgers, meat loaf (3.1%)

4. Pizza (3.1%)

5. Potato chips, corn chips, popcorn (2.9%)

6. Rice (2.7%)

7. Rolls, buns, English muffins, bagels (2.7%)

8. Cheese or cheese spread (2.6%)

9. Beer (2.6%)

10. French fries, fried potatoes (2.2%)

Source: Block, G. 2004. Foods contributing to energy intake in the U.S.: Data from NHANES III and NHANES 1999–2000. Journal of Food Composition and Analysis 17: 439–447.

Dietary guidelines for americans6
Dietary Guidelines for Americans

  • Choose and prepare foods with little salt

    • 2300 mg daily limit

    • 1500 mg daily limit for older adults, African Americans, and people with hypertension

  • Consume potassium-rich foods

    • Leafy green vegetables, sweet and white potatoes, winter squash, soybeans, tomato sauce, bananas, peaches, apricots, cantaloupes, and orange juice

Dietary guidelines for americans7
Dietary Guidelines for Americans

  • If you drink alcoholic beverages, do so in moderation, in situations that do not put yourself or others at risk

    • No more than 2 drinks per day for men

    • No more than 1 drink per day for women

    • Some groups should not drink at all

Dietary guidelines for americans8
Dietary Guidelines for Americans

  • Keep foods safe to eat

  • To prevent foodborne illness, handle, cook, and store foods in ways that prevent microorganisms from spreading and multiplying


  • Consume a balance of servings from each food group; the amount of food recommended from each food group is determined by total caloric intake

  • Engage in daily physical activity

  • Obtain a personalized plan by visiting

Mypyramid grains
MyPyramid: Grains

  • Half of daily servings should be whole grains

  • 6 ounce-equivalents daily for a 2000-calorie diet

  • 1 ounce-equivalents:

    • 1 slice of bread

    • 1 small (2-1/2-inch diameter) muffin

    • 1 cup ready-to-eat cereal flakes

    • 1/2 cup cooked cereal, rice, grains, or pasta

    • 1 6-inch tortilla

Mypyramid vegetables
MyPyramid: Vegetables

  • Consume daily servings from several different subgroups:

    • Dark green vegetables

    • Orange and deep yellow vegetables

    • Legumes

    • Starchy vegetables

    • Other vegetables

  • 2-1/2 cups (5 servings) daily for a 2000-calorie diet

Mypyramid vegetables1
MyPyramid: Vegetables

  • 1/2-cup equivalents (1 serving):

    • 1/2 cup raw or cooked vegetables

    • 1 cup raw leafy salad greens

    • 1/2 cup vegetable juice

Mypyramid fruits
MyPyramid: Fruits

  • 2 cups (4 servings) daily for a 2000-calorie diet

  • Citrus fruits and juices, melons, bananas, berries, pears, and apples are good choices

  • 1/2-cup equivalents (1 serving):

    • 1/2 cup raw or cooked vegetables

    • 1 cup raw leafy salad greens

    • 1/2 cup vegetable juice

Mypyramid milk
MyPyramid: Milk

  • 3 cups daily for a 2000-calorie diet

  • Favor low-fat and fat-free items

  • 1-cup equivalents (1 serving):

    • 1 cup milk or yogurt

    • 1/2 cut ricotta cheese

    • 1-1/2 ounces natural cheese

    • 2 ounces processed cheese

Mypyramid meat
MyPyramid: Meat

  • 5-1/2 ounce-equivalents daily for a 2000-calorie diet

  • Choose lean cuts of meat, skinless poultry, and plant proteins

  • 1-ounce equivalents:

    • 1 ounce cooked lean meat, poultry, or fish

    • 1/4 cup cooked dry beans (legumes) or tofu

    • 1 egg

    • 1 tablespoon peanut butter

    • 1/2 ounce nuts or seeds

Mypyramid oils
MyPyramid: Oils

  • Oils and soft margarines that are added to foods during processing, cooking, or at the table

  • 6 teaspoons daily for a 2000-calorie diet

  • 1 teaspoon equivalents:

    • 1 teaspoon vegetable oil or soft margarine

    • 1 tablespoon salad dressing or light mayonnaise

  • Foods that are mostly oils include nuts, olives, avocados, and some fish

Mypyramid discretionary calories
MyPyramid: Discretionary Calories

  • If all servings from the basic food groups in MyPyramid are consumed in nutrient-dense forms, additional calories can be consumed—the discretionary calorie allowance

  • Solid fats

    • Higher-fat meats, chicken with skin, full-fat dairy

    • Butter

  • Added sugars

    • Sugars added to foods (sweetened foods and beverages)

The vegetarian alternative
The Vegetarian Alternative

  • Types of vegetarian diets

    • Vegan = vegetarian who eats no animal products

    • Lacto-vegetarian = vegetarian who includes milk and cheese products in the diet

    • Lacto-ovo-vegetarian = vegetarian who includes milk and cheese products and eggs in the diet

    • Partial vegetarian, semivegetarian, or pescovegetarian = vegetarian who includes eggs, dairy products, and small amounts of poultry and seafood in the diet

Vegetarian diets and health
Vegetarian Diets and Health

  • Vegetarian diets tend to be lower in saturated fat and cholesterol and higher in complex carbohydrates, fiber, folate, vitamins C and E, carotenoids, and phytochemicals

  • MyPyramid can be used for dietary planning

  • Nutrients of concern for vegetarians include vitamin B-12, vitamin D, calcium, iron, and zinc

Dietary challenges for special population groups
Dietary Challenges for Special Population Groups

  • Women—nutrient density, calcium, iron

  • Men—fruits, vegetables, grains

  • College students—overall quality of food choices

  • Older adults—nutrient density, fiber, vitamin B-12

  • People with special health concerns— discuss with physician or dietitian

Dietary challenges for special population groups athletes
Dietary Challenges for Special Population Groups: Athletes

  • Energy intake—adequate calories and nutrients

  • Carbohydrates—60 to 65% of total daily calories for most athletes, up to 70% for endurance athletes

  • Protein (grams per day per kilogram of body weight)

    • Endurance athletes: 1.2 to 1.4 grams

    • Heavy strength training: 1.6 to 1.7 grams

  • Fluids—remain hydrated

    • 14 to 22 oz of fluid two hours before strenuous event

    • 6 to 12 oz every 15–20 minutes during exercise

    • Replace fluids after event (check body weight)

Nutritional planning making informed choices about food
Nutritional Planning: Making Informed Choices About Food

  • Food labels

  • Dietary supplement labels

  • Food additives

  • Foodborne illness

Dietary supplements
Dietary Supplements

  • May contain powerful bioactive chemicals

  • Not regulated the way drugs are by the FDA in terms of testing and manufacture

  • May interact with prescription and over-the-counter drugs and supplements

Food additives
Food Additives

  • Most widely used are sugar, salt, corn syrup, citric acid, baking soda, vegetable colors, mustard, pepper

  • Concerns about some additives:

    • Monosodium glutamate (MSG) causes some people to experience episodes of sweating and increased blood pressure

    • Sulfites cause severe reactions in some people

    • Check food labels

Foodborne illness
Foodborne Illness

  • Most foodborne illness is caused by pathogens (disease-causing microorganisms)

  • You can’t tell by taste, smell, or sight whether a food is contaminated

  • To prevent foodborne illness, handle, cook, and store foods in ways that prevent microorganisms from spreading and multiplying

  • New threat: bovine spongiform encephalopathy (BSE or “mad cow disease”)

Food safety

  • Cook foods to an appropriate temperate

  • Keep hot foods hot and cold foods cold

Irradiated foods
Irradiated Foods

  • Food irradiation = treatment of foods with gamma rays, X rays, or high-voltage electrons to kill potentially harmful pathogens and increase shelf life

Organic foods
Organic Foods

  • Organic = a designation applied to foods grown and produced according to strict guidelines limiting the use of pesticides, nonorganic ingredients, hormones, antibiotics, genetic engineering, irradiation, and other practices

  • Organic foods tend to have lower levels of pesticide residues than conventionally grown crops

Guidelines for fish consumption
Guidelines for Fish Consumption

  • To avoid harmful effects of mercury, guidelines have been set for women who are or who may become pregnant, as well as nursing mothers:

    • Do not eat shark, swordfish, king mackerel, tilefish

    • Eat up to 12 ounces per week of a variety of fish and shellfish; limit consumption of albacore tuna to 6 ounces per week

    • Check advisories about locally caught fish; if no information is available, limit to 6 ounces per week

  • Same guidelines for children, but smaller servings

  • To avoid exposure to PCBs in farmed fish, some experts recommend a limit of 8 ounces of farmed salmon per month

A personal plan applying nutritional principles
A Personal Plan: Applying Nutritional Principles

  • Assess your current diet

  • Set goals for change

  • Try additions and substitutions to bring your current diet closer to your goals

  • Plan ahead for challenging situations



Chapter 8