Chapter Eight (c) 2013 McGraw-Hill Higher Education. All rights reserved.

Chapter Eight

(c) 2013 McGraw-Hill Higher Education. All rights reserved.

Nutritional Requirements: Components of a Healthy Diet

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

There are 45 essential nutrients broken down into six classifications: Proteins Carbohydrates Fats Vitamins Minerals Water

2 (c) 2013 McGraw-Hill Higher Education. All rights reserved.

Nutritional Requirements: Components of a Healthy Diet Six classes of essential nutrients, three

supply energy: Fat = 9 calories per gram Protein = 4 calories per gram Carbohydrate = 4 calories per gram

One kilocalorie represents the amount of heat it takes to raise the temperature of 1 liter of water 1 degree centigrade


The Digestive System


Proteins—The Basis of Body Structure Proteins form key parts of the body’s main structural

components—muscles and bones—and of blood, enzymes, cell membranes, and some hormones

The building blocks of protein are amino acids Types of Protein

Complete (meat sources) Incomplete (plant sources)

Adequate daily protein intake for adults is .8 grams per kg of body weight

AMDR for protein for adults is 10-35% of total daily calories

5

Refer to Table 8.2 for popular foods and the amount of protein


Fats—Essential in Small Amounts Fats, also known as lipids, supply energy, insulate the

body, support and cushion organs, absorb fat-soluble vitamins, and add flavor and texture to foods

Types of fats: Saturated Unsaturated

Monounsaturated Polyunsaturated

Hydrogenation Trans fatty acids

Recommended intake: Men

17 g of linoleic acid and 1.6 g of alpha-linoleic acid Women

12 g of linoleic acid and 1.1 g of alpha-linoleic acid AMDR for total fat is 20-35% of total calories


The Parts of a Whole Grain Kernel


Trans Fatty Acids Trans fat is an unsaturated fatty acid produced

during the process of hydrogenation Hydrogenation is a process in which hydrogen

is added to unsaturated fats, turning liquid fats into solids

Many prepared foods use this process In large amounts, trans fats can lower HDL

(good cholesterol) levels and promote the risk of heart disease

For heart health, it is important to limit your consumption of both saturated and trans fats by examining ingredients in food products


Fats and Health Many studies have examined the role of dietary fats on

blood cholesterol levels and the risk of heart disease Most Americans consume more saturated fats than trans

fats, both of which can raise LDL (low density lipoprotein/bad cholesterol)

Monounsaturated fatty acids and polyunsaturated fatty acids improve cholesterol levels (increase levels of high-density lipoprotein (HDL)) and have a number of heart healthy effects Omega-3

Primary fish Dark green leafy vegetables Walnuts and flaxseeds Canola oil

Omega -6 Corn and soybean oil

In addition to heart disease risk, dietary fats from red meat can raise the risk of cancer, especially colon cancer


Types of Fatty Acid

10

Figure 8.3 Types of fatty acids and their possible effects on health


Carbohydrates—An Ideal Source of Energy

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

Caloric value: 4 calories/gram

There are two main types: Simple (one or two sugar units/molecule) Complex (more than two sugar units/molecule) Recommended levels:

225-325 grams based on a 2000 calorie intake/day AMDR recommends 45-65% of total daily calories

Carbohydrates are broken down into glucose, its simplest form


Refined Carbohydrates vs. Whole Grains

Whole grains have higher nutritional values compared to refined carbohydrates in the following: fiber, vitamins, minerals, and other beneficial

compounds Whole grains (unrefined carbs) take longer to

chew and digest, resulting in: making people feel full sooner entering the bloodstream more slowly reducing the possibility of overeating slower rise of blood sugar


Glycemic Index and Glycemic Response

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

Foods with a high glycemic index cause quick and dramatic rise in blood sugar levels

Diets rich in high glycemic index foods are linked to increased risk of diabetes and heart disease as well as increasing caloric intake

High fiber foods and unrefined carbohydrates tend to have a lower glycemic index


What Is Fiber? Dietary fiber is the term for nondigestible

carbohydrates that are intact in plant sources Functional Fiber is the term for nondigestible

carbohydrates has been isolated or synthesized in a lab and then added to food as a supplement.

Fiber passes through the intestinal tract and provides bulk for feces, assisting with bowel elimination

Types of fiber Soluble (viscous) fiber: slows the body’s absorption of glucose,

binding cholesterol-containing compounds in the intestines Insoluble fiber: binds with water, allowing fecal matter to

become bulkier and softer Sources of Dietary Fiber

All plant food contain fiber; however, fruits, legumes, and oats contain higher amounts

RDA for Fiber 38 grams for adult men 25 grams for adult women


Vitamins—Organic Micronutrients

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

Types of Vitamins: fat-soluble (A, D, E, and K) water-soluble (C and the eight B-complex vitamins:

thiamin, riboflavin, niacin, vitamin B-6, folate, vitamin B-12, biotin, and pantothenic acid)

Sources of Vitamins Vitamins are abundant in fruits, vegetables, and grains;

they are also added to some processed foods


Minerals—Inorganic Micronutrients

Minerals are 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 (those needed in small

amounts) include: copper, fluoride, iodide, iron, selenium, and zinc


Water

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

Water is used in digestion and absorption in food and is the medium for most chemical reactions that take place in the body

Recommendations: Women need to drink about 9 cups (2.2 liters) of

fluid per day Men need to drink about 13 cups (3.7 liters) of

fluid per day Water is lost every day through urine, feces, sweat,

and evaporation.


Other Substances in Food: Antioxidants

Antioxidants are substances that protect against the breakdown of body constituents by free radicals; actions include binding oxygen, donating electrons to free radicals, and repairing damage to molecules Free radicals are chemically unstable, electron-

seeking compounds 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

Antioxidants also fall into a broader category of phytochemicals, substances found in plant foods that help prevent chronic diseases


Nutritional Guidelines: Planning Your Diet

Various tools have been created by scientific and government groups to help people design healthy diets

The following are considered guidelines to use as a reference: Dietary Reference Intakes (DRIs)

Recommended Dietary Allowance (RDA) Adequate Intake (AI)

Daily values Dietary Guidelines for Americans ChooseMyPlate (new 2010 USDA Dietary

Guidelines) DASH


Nutrient Density of 12-ounce Portions of Selected Beverages

20

Note that regular soda is the leading source of both added sugars and calories in the American diet, but it provides few nutrients except sugar.


MyPlate Food Intake Patterns


The Vegetarian Alternative Types of vegetarian diets Vegans = vegetarian who eats no animal

products Lacto-vegetarians = vegetarian who includes

milk and cheese products in the diet Lacto-ovo-vegetarians = vegetarian who

includes milk, cheese products, and eggs in the diet

Partial vegetarians, semivegetarians, or pescovegetarians = vegetarian who includes eggs, dairy products, small amounts of poultry and seafood in the diet


Dietary Challenges for Special Population Groups Some populations face special dietary

challenges, including: Women lacking nutrient-dense foods,

calcium, iron Men needing more fruits, vegetables, grains College students should improve overall

quality of food choices Older adults need nutrient-dense foods,

fiber, vitamin B-12 Athletes need increased energy and fluid

requirements People with special health concerns should

discuss this with their physician or dietitian23


Nutritional Planning: Making Informed Choices About Food

Read food labels Read dietary

supplement labels Food additives Foodborne illness

pathogens

Irradiated foods Environmental

contaminants and organic foods


Food Additives

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


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

Follow the same guidelines for children but in 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

Assessing and changing your diet Staying committed to a healthy diet Try additions and substitutions to

bring your current diet closer to your goals

Plan ahead for challenging situations


Chapter Eight


Chapter Eight (c) 2013 McGraw-Hill Higher Education. All rights reserved.

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