Chapter 2 Lecture Slides

Transcription

1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 2 Lecture Slides Essential Nutrients and Recommended Nutrient Intakes Foods we eat Essential nutrients Nonessential nutrients Other substances Amounts of nutrients recommended Dietary Reference Intakes (DRIs) What are essential nutrients? Essential nutrients cannot be produced in adequate quantities in body and must be consumed in diet Six major classes of essential nutrients Carbohydrate Fats Protein Vitamins Minerals Water

2 Essential or probably essential nutrients Carbohydrates Fiber and sugar and starches Fats Essential fatty acids (Linoleic and alpha-linolenic) Protein 9 essential amino acids Vitamins 9 water soluble and 4 fat soluble Minerals Over 20 minerals Water Essential nutrients Macronutrients (gram quantity) Carbohydrate Fat Protein Water Micronutrients (milligram or microgram quantity) Vitamins Minerals Essential nutrients Essential for life Some foods contain all six classes of nutrients Whole wheat bread Some foods contain only one class Refined table sugar

3 Figure 2.1 What are nonessential nutrients? Nonessential nutrients (Dispensable nutrients) Found in food but may also be formed in the body Creatine is an example Needed for one form of energy production Found in food, mainly animal foods Produced in the body from amino acids Non-nutrients Found naturally in or added to foods Plant sterols Caffeine Examples of nonessential nutrients and other substances found in food Nonessential nutrients Carnitine Food drugs Caffeine Phytochemicals Flavonoids Extracts Ginseng Antinutrients Tannins

4 How are recommended dietary intakes determined? Food and Nutrition Board, Institute of Medicine of the National Academy of Sciences 1941: First set of Recommended Dietary Allowances (RDA) Dietary Reference Intakes (DRIs) represent the current standards Recommended Dietary Allowance (RDA) Adequate Intake (AI) Acceptable Macronutrient Distribution Range (AMDR) Tolerable Upper Intake Level (UL) Estimated Average Requirement (EAR) Estimated Energy Requirement Estimated Average Requirement (EAR) The EAR represents a nutrient intake that is estimated to meet the requirement of half the healthy individuals in a population The EAR is used to establish the RDA The RDA is some multiple of the EAR Recommended Dietary Allowance (RDA) The RDA represents the average daily dietary intake that is sufficient to meet the nutrient requirement of nearly all (97%-98%) healthy individuals in a population. The RDA is to be used as a guide for the individual

5 Acceptable Macronutrient Distribution Range (AMDR) The AMDR is defined as a range of intakes for a particular energy source (macronutrient). The AMDR is expressed as a percentage of total energy intake. Carbohydrate: 45-65% Fat: 20-35% Protein: 10-35% Tolerable Upper Intake Level (UL) The UL is the highest level of daily nutrient intake that is likely to pose no risks of adverse health effects to most individuals in the general population. Consider it a maximum for daily intake of a specific nutrient on a long-term basis. Estimated Energy Requirement (EER) The EER is an estimate of the amount of energy needed to sustain requirements for daily physical activity. Discussed in detail in Chapter 3. Useful for weight control discussed in chapter 11.

6 Interpreting the DRI Used to assess adequacy of dietary intake Used to plan diets for individuals and groups Designed to ensure adequate nutrition for most people in a population Diet on any day is not necessarily deficient if RDA is not obtained Intake should be averaged over a 5-8 day period Does not inform us of what specific foods to eat Note: Another term, the Daily Value (DV) is used on food labels, discussed later. The Balanced Diet and Nutrient Density The balanced diet Variety Moderation Concept A balanced diet will provide the required amounts of essential nutrients The Balanced Diet and Nutrient Density The balanced diet Variety Moderation

7 Individuality Age Gender Health status Sport The Balanced Diet What foods should I eat to obtain the nutrients I need? History Basic Seven Basic Four Current status Food Guide for Americans Revised every 5 years MyPyramid Food Guide (2005) First guide to include physical activity Other guides The Food Exchange System American Dietetic and American Diabetes Associations Current food groups Milk, yogurt and cheese Meat, poultry, fish, dry beans, eggs, nuts Bread, cereal, rice, pasta Vegetables Fruits Fats, oils, sweets (Not an official food group)

8 Nutrients in different food groups Milk, yogurt, cheese Calcium Protein Riboflavin Vitamins A, D Meat, poultry, fish, dry beans, eggs, nuts Protein B vitamins Iron Zinc Nutrients in different food groups Bread, cereal, rice, pasta B vitamins Iron Fiber Vegetables Vitamin A (carotene) Vitamin C Iron Fiber Nutrients in different food groups Fruits Vitamin A (carotene) Vitamin C Fiber Fats, oils Vitamin A Vitamin D Vitamin E

9 What is the MyPyramid food guide? Steps to a healthier you Variety Proportionality Moderation Activity Gradual improvement Personalization Figure 2.3 MyPyramid Access at Enter demographic data Develop an individualized food plan Use MyPyramid Tracker for detailed assessment Excellent dietary assessment tool Analyzes current diet and physical activity Tracks both for up to a year Obtain detailed information about each food group MyPyramid for Kids is available Information for health professionals

10 Figure 2.4 Key food group messages from the Dietary Guidelines and MyPyramid: Focus on fruits. Vary your veggies. Get your calcium-rich foods. Make half your grains whole. Go lean with protein. Know the limits on fats, salt, and sugars. MyPyramid serving size Milk 1 cup of milk or yogurt 1.5 ounces of natural cheese 2 ounces of processed cheese

11 MyPyramid serving size Meat 1 ounce of cooked lean meat, poultry or fish 0.25 cup of cooked dry beans 1 egg 1 tablespoon peanut butter MyPyramid serving size Grains 1 slice of bread 1 ounce of ready-to-eat cereal 0.5 cup of cooked cereal, rice, or pasta MyPyramid serving size Vegetable 1 cup of raw, leafy vegetables 0.5 cup of other vegetables, cooked or chopped raw 1 cup of vegetable juice

12 MyPyramid serving size Fruit 1 medium apple, banana, or orange 1 cup of chopped, cooked, or canned fruit 1 cup of fruit juice 0.5 cup dried fruit Oil 1 teaspoon MyPyramid serving size

13 MyPyramid Tracker A tool for those desiring a more advanced analysis of their food intake and physical activity

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15 What is the Food Exchange System? Developed by the American Dietetic Association and American Diabetes Association Foods in an exchange contain similar nutrient and caloric value Six food exchanges Milk exchange Meat and meat substitutes exchange Starch exchange Fruit exchange Vegetable exchange Fat exchange Food Exchange Groups Food Exchange Milk (1 cup) Carbohydrate Fat Protein Calories Skim/very low fat Low fat Whole Meat/substitutes (1 oz) Very lean Lean Medium fat High fat Starch (1 oz; ½ cup) Fruit (1 medium; ½ cup) Vegetable (1/2 cup) Fat (1 teaspoon) Carbohydrate, fat and protein in grams per serving 1 g carbohydrate = 4 Calories; 1 gram fat = 9 Calories; 1 gram protein = 4 Calories

16 What is the key-nutrient concept for obtaining a balanced diet? The key-nutrient concept indicates that obtaining adequate amounts of 8 key nutrients from natural, wholesome foods will provide adequate amounts of other essential nutrients. Eight key nutrients and significant food sources from plants and animals Protein Beans, Peas Meat, fish Vitamin A Color vegetables Fortified milk Vitamin C Citrus fruits Liver Thiamin Grains Pork, ham Riboflavin Grains Milk, cheese Niacin Grains Meat, poultry Iron Beans, peas Meat, liver Calcium Spinach, kale Milk

17 Eight key nutrients and significant food sources from plants and animals What is the concept of nutrient density? Foods that contain a significant amount of a specific nutrient compared to its caloric content have a high nutrient density. May be referred to as Quality Calories. Figure 2.6

18 Nutrient density Yale University has developed an Overall Nutritional Quality Index (ONQI) which rates foods on a scale from 1 to 100 based on nutrient content and health concerns. Broccoli scores 100, while soda scores 1. Will use of MyPyramid Food Guide or the Food Exchange System guarantee me optimal nutrition? Nutritionists indicate that the recommendations in MyPyramid are remarkably consistent with the various recommendations to control most chronic diseases. MyPyramid itself does not indicate what specific foods to eat for health, but does provide specific guidelines on its website. Healthy eating focuses on the total diet, not one food. Select foods with lower amounts of fat and sugar. Healthy Eating Cost of healthy eating Energy-dense foods high in sugar and fat $1.76 for 1,000 Calories Fruits, vegetables and other healthier foods $18.16 for 1,000 Calories Reducing the cost of healthy eating Choose seasonal fruits and vegetables Capitalize on store specials on fresh chicken, fish Separate into smaller packages and freeze Purchase whole grain products in bulk Buy bags of frozen vegetables; cheaper and less spoilage

19 Healthful Dietary Guidelines Nutritional guidelines developed to help minimize the risk of various chronic diseases. Coronary heart disease Stroke Cancer Diabetes Osteoporosis Obesity High blood pressure What is the basis underlying the development of healthful dietary guidelines? Concept that the development of most chronic diseases may be associated with either deficiencies or excesses of various nutrients or food constituents in the diet. Earlier guidelines based on epidemiological research, which may have led to some erroneous recommendations. Current guidelines are evolving as more long-term experimental studies are conducted. The Optimal Macronutrient Intake Trial to Prevent Heart Disease (OmniHeart) Type of carbohydrate, fat and protein could have favorable effects No absolute proof, but prudent recommendations What are the recommended dietary guidelines for reducing the risk of chronic diseases? Synthesis of various reports from professional and governmental health organizations American Cancer Society American Diabetes Association American Dietetic Association American Institute of Cancer Research Harvard School of Public Health United States Department of Agriculture United States Department of Health and Human Services

20 Prudent Recommendation 1. Balance the food you eat with physical activity to maintain or achieve a healthy body weight. Prudent Recommendation 2. Eat a nutritiously adequate diet consisting of a wide variety of nutrient-rich foods. Prudent Recommendation 3. Choose a diet moderate in total fat, but low in saturated and trans fats and cholesterol. Choose plant oils or other healthy fats Eat less meat with high fat content; choose lean poultry Eat more fish Eat only several eggs per week Eat fewer high-fat dairy products Eat less butter; use soft or specialty margarines Eat fewer commercial baked goods Limit consumption of fast foods Use food labels to help you select foods low in fat Broil, bake or microwave instead of cooking in oil

21 Prudent Recommendation 4. Choose a plant-rich diet with plenty of fruits and vegetables, whole-grain products, and legumes, foods which are rich in complex carbohydrates, phytochemicals, and fiber. Fruits and Veggies: More matters Prudent Recommendation 5. Choose beverages and foods to moderate your intake of added sugars. Moderate intake Sodas Juice drinks Fruit juices Drink more Tap water Prudent Recommendation 6. Choose and prepare foods with less salt and sodium. Get rid of your salt shaker Reduce the consumption of obviously high-salt foods Check food labels for sodium content Eat more fresh fruits and vegetables Use fresh herbs or spices that do not contain sodium Use lite salt

22 Prudent Recommendation 6. Choose and prepare foods with less salt and sodium. Prudent Recommendation 7. If you drink alcoholic beverages, do so in moderation. Prudent Recommendation 8. Maintain protein intake at a moderate, yet adequate level, obtaining much of your daily protein from plant sources complemented with smaller amounts of fish, skinless poultry, and lean meats. Current protein intake in the United States is 70 percent animal protein 30 percent plant protein Recommended protein intake is 30 percent animal protein 70 percent plant protein

23 Prudent Recommendation 9. Choose a diet adequate in calcium and iron. Individuals susceptible to tooth decay should obtain adequate fluoride. Prudent Recommendation 10. Practice food safety, including proper food preservation and preparation. Store foods properly Wash hands thoroughly Avoid charring of meats Prudent Recommendation 11. Consider the benefits and risks of food additives and dietary supplements.

24 Prudent Recommendation 12. Enjoy your food! Eat what you like, but balance it within your overall healthy diet. Vegetarianism What types of food does a vegetarian eat? Vegan No animal products at all Ovovegetarian Eats eggs Lactovegetarian Eats dairy products Ovolactovegetarian Eats eggs and dairy products Pescovegetarian Eats fish Semivegetarian Eat fish and white poultry meat

25 What are some of the nutritional concerns with a vegetarian diet? Calories Inadequate Calories May be a problem for children and athletes May be advantage for weight control Vitamins B12 not found in natural plant foods Minerals Diets may be low in iron, calcium and zinc Protein Grains low in lysine; legumes low in methionine Vegan diet should contain complementary proteins Combining foods for protein complementarity Is a vegetarian diet more healthful than a nonvegetarian diet? Nutrient density

26 Is a vegetarian diet more healthful than a nonvegetarian diet? Low fat and cholesterol High fiber content Low caloric content High vitamin High phytochemical content Nutraceuticals

27 Potential health benefits of antioxidants and phytochemicals Eating the colorful way How can I become a vegetarian? Eat more fruits, vegetables and whole grains Become a part-time vegetarian. Eat less red meat. Become a semivegetarian. Become an ovolactovegetarian Eat a vegan diet a couple of days each week Use these websites

28 Will a vegetarian diet affect physical performance potential? Limited research with vegetarian diets and exercise performance Some world class athletes have been vegetarians Pros Rich in carbohydrates Fortified foods may provide adequate vitamins and minerals Plant and animal protein appear to be adequate Cons At risk for non-anemic iron deficiency or iron deficiency anemia Lower muscle creatine levels may possibly affect performance Consumer Nutrition: Food Labels and Health Claims What nutrition information do food labels provide? Nutrition Facts Figure 2.7

29 Consumer Nutrition: Food Labels and Health Claims What nutrition information do food labels provide? Nutrition Facts How can I use this information to select a healthier diet? The Daily Value (DV) Based on some of the DRI values Those listed based on 2,000 Calorie intake (Adult female) The % of the DV on the label is for a 2,000 Calorie intake Some information for 2,500 Calorie intake (Adult male) Some DV values are outdated as they are based on earlier RDA values (U. S. RDA) Daily Value The DVs are based pm certain minimum and maximum allowances, including the following for a 2,000 Calorie diet:

30 Figure 2.10

31 Definitions for comparative and absolute nutrient claims on food labels Definitions for comparative and absolute nutrient claims on food labels Definitions for comparative and absolute nutrient claims on food labels

32 Definitions for comparative and absolute nutrient claims on food labels Definitions for comparative and absolute nutrient claims on food labels Definitions for comparative and absolute nutrient claims on food labels

33 Definitions for comparative and absolute nutrient claims on food labels Definitions for comparative and absolute nutrient claims on food labels Definitions for comparative and absolute nutrient claims on food labels

34 Definitions for comparative and absolute nutrient claims on food labels Cool Website The FDA provides a program, Make Your Calories Count, featuring the animated character Labelman, to help people read food labels to plan a healthy die while balancing caloric intake. What health claims are allowed on food products?

35 What are functional foods? Functional foods are food products designed to provide health benefits beyond basic nutrition, the benefits being attributed mostly to vitamins, minerals, phytochemicals, and herbals. Natural foods may be fortified Example: Calcium-fortified orange juice The ADA indicates some may have a beneficial effect if consumed within a varied diet on a regular basis. Some products may not be healthful Example: Sugar drink with added vitamins Consumer Nutrition: Dietary Supplements and Health

36 What are dietary supplements? Defined by the Dietary Supplement Health and Education Act (DSHEA) of 1994, a dietary supplement is a food product, added to the total diet, that contains at least one of the following ingredients. Vitamin Mineral Herb or botanical Amino acid Metabolite Constituent Extract Combination of any of these ingredients Dietary Supplements Like foods, dietary supplements must carry labels, or Supplement Facts.

37 Will dietary supplements improve my health? Best nutritional advice is to obtain nutrients through natural, wholesome foods. Some may benefit from dietary supplements Example: Vitamins for elderly, women of childbearing age Most herbals not adequately researched Products often are mislabeled Supplements may carry structure/function claims This statement has not been evaluated by the FDA. Burden of proof is on the FDA Improvements in labeling expected in 2010 Dietary Supplements Can dietary supplements harm my health? Possibly. Users of dietary supplements may disregard other very important lifestyle behaviors. provide a false sense of security, thus one may not eat right take excessive dosages, which may be harmful. may use supplements as alternative medicine, and not seek proper medical advice. take supplements that are contaminated. take potentially harmful supplements, such as ephedra.

38 Dietary Supplements Some general safeguards by Consumers Union Before trying a supplement to improve your health, try changing your diet and lifestyle first Check with your doctor, especially with herbals. Buy standardized products; USP rating is helpful Use only single ingredient supplements Be alert to positive and negative effects Stop taking the supplement if you experience problems; report problems to physician or local health authorities. Cool Website Check dietary supplements by specific brands or active ingredients. Indicates uses for the product. Provides list of research studies regarding effectiveness. Consumer Nutrition: Food Quality and Safety FDA Center for Food Safety and Applied Nutrition Regulates food quality and safety However, foods not necessarily risk free or high quality Food safety is in 2005 Dietary Guidelines for Americans

39 Is current food biotechnology effective and safe? Historical aspects Breeding of plants and animals for higher quality foods Genetic engineering; genetic modification (GM) Rice designed to contain more beta-carotene Salmon engineered to grow faster and larger Foods regulated by FDA, USDA and EPA 70% of foods in typical supermarket contain at least one GM ingredient GM foods generally recognized as safe Not labeled in US except under certain circumstances Do pesticides or herbicides in food present significant health risks? Plants contain natural phytochemicals that function as herbicides and pesticides Synthetic herbicides and pesticides Used to protect plants Function differently in the human body May cause health problems Occupational exposure (farm workers) Current scientific reports Trace amounts in foods not harmful to adults Chronic exposure may cause health problems in children Pesticides and Herbicides Advice based on current research: Avoid direct skin contact or breathing Prepare foods carefully; wash thoroughly Eat less animal fat and fish from contaminated waters Buy fruits and vegetables locally in season Eat a wide variety of foods Buy certified organic foods

40 Pesticides in Foods The Dirty Dozen and the Clean Dozen Are organic foods safer and healthier choices? Foods that are % organic can carry the USDA organic label. Foods that contain at least 70% organic ingredients may use Made With Organic Ingredients, but cannot use the label. Organic Foods vs Conventional Foods Pesticides Organic foods contain fewer pesticides Significance of the difference, however, is questionable The clean dozen have few pesticides Bacteria Bacteria levels in organic fruits, vegetables and chicken similar to conventional foods Organic does not mean safe Nutritional value Differences are questionable Organic junk foods, such as organic soda

41 Does commercial food processing affect food quality and safety? Potential beneficial effects May preserve high nutrient value (flash frozen) Nutrients may be added (enriched; fortified) Potential harmful effects Adding too much sugar and fat Addition of questionable additives Removing essential nutrients such as vitamins and minerals Inadvertent inclusion of bacteria Does home food processing affect food quality and safety Tips for food processing at home Keep most fruits and vegetables in the refrigerator Keep frozen foods frozen until ready for use Keep milk, grains in opaque containers Prevent destruction of riboflavin Steam or microwave vegetables in little water Avoid cooking with high temperatures Loss of water-soluble vitamins in boiling water Avoid excess cooking of foods Formation of acrylamide and heterocyclic amines (HCA) What is food poisoning? Food poisoning is caused primarily by consuming foods contaminated with certain bacteria. Salmonella Escherichia (E. coli) Staphylococcus Clostridium Campylobacter Listeria Food poisoning is the major health problem associated with home food processing.

42 Food poisoning Most common commercial sources of bacteria Raw and undercooked meat and poultry Raw or undercooked eggs Raw or undercooked shellfish Contaminated produce Improperly canned foods Most common home sources of bacteria Improper food preparation Poor sanitation Food poisoning Consumers Union 83 percent of whole chicken broilers bought nationwide, even premium and organic broilers, harbored Campylobacter or Salmonella Major outbreak associated with fresh spinach and E. coli; 31 cases of kidney failure and 3 deaths 1. Food poisoning Most common symptoms Nausea Vomiting Diarrhea More severe symptoms. Seek medical help. Headache and stiff neck Bloody or prolonged diarrhea (3 days) Fever more than 24 hours Sensations of weakness, numbness, tingling in legs

43 Preventing food poisoning Commercial food preparation Use of food preservatives Irradiation Preventing food poisoning Home food preparation Wash hands thoroughly before and during food prep Treat all raw animal foods as if contaminated Wash all fruits and vegetables thoroughly Clean thoroughly all utensils used in food preparation with hot soapy water; microwave sponges and other utensils Use a clean preparation surface Do not use canned foods that are damaged or bulging Cook all meat, poultry, seafood and eggs thoroughly Store heated foods promptly in the frig or freezer Use leftovers in a few days; if in doubt, throw it out Are food additives safe? More than 40 purposes for the use of additives Add flavor Enhance color Improve texture Preserve the food

44 Food additives Generally recognized as safe (FDA approval) Acceptable Daily Intake (ADI) developed for some foods Additives may used only In specific foods for specific purposes The Delaney Clause In general, most food additives are regarded as safe. However, some consumer protection groups stress caution with some. Cool Website The Center for Science in the Public Interest has developed a guide to safety of food additives, including the following five categories: Safe Cut back Caution Certain people should avoid Everyone should avoid Healthful Nutrition: Recommendations for Better Physical Performance Purposes of food for sport performance Provide energy Regulate metabolic processes Promote growth and development Nutrition for training Nutrition for competition

45 What should I eat during training? Ron Maughan indicates that the main role of nutrition for the athlete may be to support consistent intensive training. Chris Carmichael notes that athletes need to match their nutritional intake to the demands of training. Diet during training: Some considerations The Prudent Healthy Diet May serve as the basic diet plan The chronic training effect Focus on adequate intakes of nutrients in early training Timing of nutrient intake John Hawley notes that the beneficial effects of training are believed to occur during the recovery period Breakfast is an important meal for the athlete Breakfast for the athlete A balanced breakfast provides a significant amount of Calories and other nutrients in the daily diet Skim milk, whole grain cereal, poached egg, toast, OJ May help maintain feeling of satiety in the morning Skipping breakfast is comparable to a small fast Possible hypoglycemia May enhance academic performance

46 When and what should I eat just prior to competition? Major goals of the precompetition meal involve timing and composition Allow the stomach to be relatively empty at the start. Help to prevent or minimize gastrointestinal distress. Help avoid sensations of hunger, lightheadedness, or fatigue Provide adequate energy supplies, primarily carbohydrate, in the blood and muscles. Provide an adequate amount of body water. Examples of precompetition meals Some meal plans for competition

47 What should I eat during competition? In most sports, only fluids and carbohydrates may be necessary Specific nutrients will be discussed throughout the course as merited What should I eat after competition? In general, a balanced diet will meet nutritional needs of most athletes. Carbohydrate and fluids may be important, particularly for competition on the same or following day. Protein intake will be discussed in chapter 6. Should athletes use commercial sports foods? Sports foods may be convenient and appropriate before, during and after competition or training Should not be used as a substitute for a healthy diet Types of products Liquid sports meals Sports bars Sports gels and candy Sports supplements

48 How can I eat more nutritiously while traveling for competition? Carry your own food How can I eat more nutritiously while traveling for competition? Select healthful foods at restaurants, supermarket take-out buffets, and fast-food establishments How do gender and age influence nutritional requirements for enhanced physical performance? Gender Few differences in nutritional needs of male and female athletes Female endurance athletes may oxidize more fat Adolescent and young females need more iron Eating disorders more common in females Age Young athletes may need more Calories, protein, calcium Older athletes need fewer Calories, more vitamins B12 and D, and calcium Both need to use caution with exercise in the heat

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