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: ú
ú
ú
ú
ú
ú
Proteins Carbohydrates Fats Vitamins Minerals Water (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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Nutritional Requirements: Components
of a Healthy Diet
§  Six classes of essential nutrients, three supply energy: ú  Fat = 9 calories per gram ú  Protein = 4 calories per gram ú  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 (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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The Digestive System (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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 ú  Complete (meat sources) ú  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 Refer to Table 8.2 for popular foods and the
amount of protein
(c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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: ú  Saturated ú  Unsaturated   Monounsaturated   Polyunsaturated ú  Hydrogenation   Trans fatty acids §  Recommended intake: ú  Men   17 g of linoleic acid and 1.6 g of alpha-­‐linoleic acid ú  Women   12 g of linoleic acid and 1.1 g of alpha-­‐linoleic acid §  AMDR for total fat is 20-­‐35% of total calories (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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The Parts of a Whole Grain Kernel (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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 (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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 ú  Omega-­‐3   Primary fish   Dark green leafy vegetables   Walnuts and flaxseeds   Canola oil ú  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 (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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Types of Fatty Acid §  Figure 8.3 Types of fatty acids and their possible effects on health (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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Carbohydrates—An Ideal Source of Energy §  The primary function of dietary carbohydrate is to supply energy to body cells. §  Caloric value: ú  4 calories/gram §  There are two main types: ú  Simple (one or two sugar units/molecule) ú  Complex (more than two sugar units/molecule) ú  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 (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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Refined Carbohydrates vs. Whole
Grains
§  Whole grains have higher nutritional values compared to refined carbohydrates in the following: ú  fiber, vitamins, minerals, and other beneficial compounds §  Whole grains (unrefined carbs) take longer to chew and digest, resulting in: ú
ú
ú
ú
making people feel full sooner entering the bloodstream more slowly reducing the possibility of overeating slower rise of blood sugar (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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 (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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 ú  Soluble (viscous) fiber: slows the body’s absorption of glucose, binding cholesterol-­‐containing compounds in the intestines ú  Insoluble fiber: binds with water, allowing fecal matter to become bulkier and softer §  Sources of Dietary Fiber ú  All plant food contain fiber; however, fruits, legumes, and oats contain higher amounts §  RDA for Fiber ú  38 grams for adult men ú  25 grams for adult women (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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: ú  fat-­‐soluble (A, D, E, and K) ú  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 ú  Vitamins are abundant in fruits, vegetables, and grains; they are also added to some processed foods (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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: ú  Major minerals (those that the body needs in amounts exceeding 100 mg per day) include:   calcium, phosphorus, magnesium, sodium, potassium, and chloride ú  Essential trace minerals (those needed in small amounts) include:   copper, fluoride, iodide, iron, selenium, and zinc (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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: ú  Women need to drink about 9 cups (2.2 liters) of fluid per day ú  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. (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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 ú  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 (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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: ú  Dietary Reference Intakes (DRIs)   Recommended Dietary Allowance (RDA)   Adequate Intake (AI) ú
ú
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Daily values Dietary Guidelines for Americans ChooseMyPlate (new 2010 USDA Dietary Guidelines) DASH (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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Nutrient Density of 12-­‐ounce Portions of Selected Beverages 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.
(c) 2013 McGraw-Hill Higher Education. All rights reserved.
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MyPlate Food Intake Patterns (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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The Vegetarian Alternative
§  Types of vegetarian diets ú  Vegans = vegetarian who eats no animal products ú  Lacto-­‐vegetarians = vegetarian who includes milk and cheese products in the diet ú  Lacto-­‐ovo-­‐vegetarians = vegetarian who includes milk, cheese products, and eggs in the diet ú  Partial vegetarians, semivegetarians, or pescovegetarians = vegetarian who includes eggs, dairy products, small amounts of poultry and seafood in the diet (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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Dietary Challenges for Special
Population Groups
§  Some populations face special dietary
challenges, including:
ú  Women lacking nutrient-dense foods, calcium, iron
ú  Men needing more fruits, vegetables, grains
ú  College students should improve overall quality of
food choices
ú  Older adults need nutrient-dense foods, fiber, vitamin
B-12
ú  Athletes need increased energy and fluid
requirements
ú  People with special health concerns should discuss
this with their physician or dietitian
(c) 2013 McGraw-Hill Higher Education. All rights reserved.
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Nutritional Planning: Making Informed
Choices About Food
§  Read food labels §  Irradiated foods §  Read dietary §  Environmental supplement labels §  Food additives §  Foodborne illness contaminants and organic foods ú  pathogens (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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Food Additives
§  Most widely used are sugar, salt, corn syrup, citric acid, baking soda, vegetable colors, mustard, and pepper §  Concerns about some additives: ú  Monosodium glutamate (MSG) causes some people to experience episodes of sweating and increased blood pressure ú  Sulfites cause severe reactions in some people ú  Check food labels (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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: ú  Do not eat shark, swordfish, king mackerel, tilefish ú  Eat up to 12 ounces per week of a variety of fish and shellfish; limit consumption of albacore tuna to 6 ounces per week ú  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 (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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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 (c) 2013 McGraw-Hill Higher Education. All rights reserved.
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Chapter Eight (c) 2013 McGraw-Hill Higher Education. All rights reserved.