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Nutrition: 

Nutrition 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”

Sources of Energy in the Diet: 

Sources of Energy in the Diet

The Digestive System: 

The Digestive System

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

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 Fats: 

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

Chemical Structure of Fats: 

Chemical Structure of Fats

Comparison of Dietary Fats: 

Comparison of Dietary Fats

Total Fat Content of Foods: 

Total Fat Content of Foods

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

Trans Fatty Acids: 

Trans Fatty Acids

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 Health: 

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

Saturated and Trans Fats: Comparing Butter and Margarine: 

Saturated and Trans Fats: Comparing Butter and Margarine SOURCE: Food an Drug Administration

Total, Saturated, and Trans Fat Content of Selected Foods: 

Total, Saturated, and Trans Fat Content of Selected Foods SOURCE: Food an Drug Administration

Fats and Health: 

Fats and Health

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.

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

Glycemic Index: 

Glycemic Index

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 World Health Organization: 10% or less of total daily calories

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: 

Vitamins 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 B-6 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

Minerals: 

Minerals 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 : 

Osteoporosis—Thinning of Bones Dietary factors that build bone mass: Calcium 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: Alcohol Sodium Caffeine Retinol Soda Protein (if intake of calcium and vitamin D is low)

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

Antioxidants Donate Electrons and Stabilize Free Radicals: 

Antioxidants Donate Electrons and Stabilize Free Radicals

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 Food Guide Pyramid = a food-group plan that provides practical advice to ensure a balanced intake of essential nutrients Dietary Guidelines for Americans = general principles of good nutrition intended to help prevent certain diet-related diseases

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 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

The USDA Food Guide Pyramid: 

The USDA Food Guide Pyramid Suggests a range of servings for five major food groups Smaller number of servings are for those who consume about 1600 calories a day Larger number of servings are for those who consume about 2800 calories a day Keys are to choose a variety of foods within each group and to focus on nutrient density

The Food Guide Pyramid: A Guide to Daily Food Choices: 

The Food Guide Pyramid: A Guide to Daily Food Choices

Serving Sizes: 

Serving Sizes

Serving Sizes: 

Serving Sizes

Nutrient Density These beverages have about the same number of calories in a 12-ounce serving, but the cola and tea provide few nutrients besides added sugars (about 10 teaspoons). Orange juice and milk are rich in many nutrients. (Color bars represent percentage of recommended daily intake or limit for each nutrient.): 

Nutrient Density These beverages have about the same number of calories in a 12-ounce serving, but the cola and tea provide few nutrients besides added sugars (about 10 teaspoons). Orange juice and milk are rich in many nutrients. (Color bars represent percentage of recommended daily intake or limit for each nutrient.)

Current American Diet: 

Current American Diet The current American diet includes too many foods from the tip of the Pyramid (fats and sweets) and too many foods low in nutrients The current American diet is low in fruits, vegetables, whole grains, dietary fiber, and certain vitamins and minerals

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.

Alternative Food Plans: Healthy Eating Pyramid: 

Alternative Food Plans: Healthy Eating Pyramid

Alternative Food Plans: Canada’s Food Guide: 

Alternative Food Plans: Canada’s Food Guide

Dietary Guidelines for Americans: ABCs for Health: 

Dietary Guidelines for Americans: ABCs for Health Aim for fitness Aim for a healthy weight. If you are overweight, first prevent further weight gain and then lose weight gradually (1/2 to 2 pounds per week) to improve health. Be physically active every day. Aim to accumulate 30 minutes (adults) or 60 minutes (children) on most days—more if your goal is weight loss or maintenance of weight loss.

Dietary Guidelines for Americans: ABCs for Health: 

Dietary Guidelines for Americans: ABCs for Health Build a healthy base Let the Pyramid guide your food choices. Eat a variety of grains daily, especially whole grains. Eat a variety of fruits and vegetables daily. Favor dark-green leafy vegetables, bright orange fruits and vegetables, and cooked dried peas and beans. Keep food safe to eat.

Dietary Guidelines for Americans: ABCs for Health: 

Dietary Guidelines for Americans: ABCs for Health Choose sensibly Choose a diet low in saturated fat and cholesterol and moderate in total fat. Focus on keeping intake of saturated and trans fats as low as possible. Choose beverages and foods to moderate your intake of sugars. Limit your consumption of regular soda, candies, sweet desserts, and fruit drinks.

Dietary Guidelines for Americans: ABCs for Health: 

Dietary Guidelines for Americans: ABCs for Health Choose sensibly (continued) Choose and prepare foods with less salt. DRI for sodium = 1500 mg/day (about 2/3 teaspoon of salt) UL for sodium = 2300 mg/day The majority of Americans exceed the UL. If you drink alcoholic beverages, do so in moderation No more than 2 drinks/day for men No more than 1 drink/day for women

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 are lower in saturated fat and cholesterol and higher in complex carbohydrates, fiber, folate, vitamins C and E, carotenoids, and phytochemicals Nutrients of concern for vegetarians include vitamin B-12, vitamin D, calcium, iron, and zinc

Vegetarian Food Pyramid: 

Vegetarian Food Pyramid

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 densiy, 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

Food Labels: 

Food Labels Read labels to learn more about your food choices.

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

Dietary Supplements: 

Dietary 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: 

Food Safety Cook foods to an appropriate temperate Keep hot foods hot and cold foods cold

Irradiated Foods—A Technique of Biotechnology: 

Irradiated Foods—A Technique of Biotechnology 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 foods tend to have lower levels of pesticide residues than conventionally grown crops 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

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

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