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Nutrition Basics Chapter 12 © 2012 McGraw-Hill Higher Education. All rights reserved. Nutritional Requirements: Components of a Healthy Diet Your body requires 45 essential nutrients: ◦ Proteins, fats, carbohydrates, vitamins, minerals, water Macronutrients Micronutrients Body obtains nutrients through process of digestion Energy in food is expressed as kilocalories (kcalorie) 1 kcalorie = amount of heat it takes to raise the temperature of 1 liter of fluid 1 degree centigrade 2,000 calories per day meets a person needs. 1,000 calories = 1 kcalorie 3 categories supply energy Fat = 9 calories per gram Protein = 4 calories per gram Carbohydrates = 4 calories per gram © 2012 McGraw-Hill Higher Education. All rights reserved. 2 Table 12.1 The Six Classes of Essential Nutrients © 2012 McGraw-Hill Higher Education. All rights reserved. 3 Figure 12.1 The Digestive System © 2012 McGraw-Hill Higher Education. All rights reserved. 4 Proteins – Basis of Body Structure Form muscle, bone, blood, enzymes, hormones, cell membranes ◦ Twenty common amino acids – building blocks Nine essential amino acids Eleven nonessential amino acids ◦ Complete proteins provide all essential amino acids Most animal proteins provide complete proteins Most plant proteins are incomplete Plants, legumes, nuts Combine 2 vegetables to make up missing amino acids ◦ Recommended amount 0.36 grams per pound of body weight 10-35% of total calorie intake Average is 15-16% © 2012 McGraw-Hill Higher Education. All rights reserved. 5 Fats (or Lipids) Essential in small amounts Most concentrated source of energy (9 cals/gram) ◦ Stored energy, provides insulation and support for body organs ◦ Two fats are essential components of diet Linoleic acid Alpha-linolenic acid ◦ 10% from saturated fats ◦ Triglycerides - glycerol molecule with 3 fatty acid chains Animal fats primarily made of triglycerides Unsaturated Monounsaturated Polyunsaturated Saturated Hydrogenation Trans fatty acids © 2012 McGraw-Hill Higher Education. All rights reserved. 6 Fats and Health Cholesterol ◦ Low density lipoprotein (LDL) – “bad” cholesterol ◦ High density lipoprotein (HDL) – “good” cholesterol Absorbs fat-soluble vitamins (A,D,E, K) Omega-3 fatty acids – AMDR 5-10% Omega-6 fatty acids – AMDR 0.6-1.2% Recommended intake ◦ Adults Men 17 grams per day of linoleic and 1.6 grams of alpha-linolenic Women 12 grams per day of linoleic and 1.1 grams of alpha-linolenic ◦ Only 3-4 teaspoons (15-20 grams) of vegetable oil per day ◦ AMDRs for total fat 20-35% © 2012 McGraw-Hill Higher Education. All rights reserved. 7 Carbohydrates Supply energy for body cells Two groups ◦ Simple carbs: one or two sugar units Fruit, sugar, honey, malt, and milk ◦ Complex carbs: multiple sugar units Starches and fiber Grains – wheat, rye, rice, oats, barley, millet Legumes – dry beans, peas, lentils Tubers – potatoes, yams ◦ Digestion Mouth and small intestines Break down to glucose © 2012 McGraw-Hill Higher Education. All rights reserved. 8 Refined Carbohydrates versus Whole Grains Refined (processed) Unrefined (whole grains) All grains before processing ◦ Inner layer: germ ◦ Middle layer: endosperm ◦ Outer layer: bran During processing ◦ Germ and bran are removed, leaving just the starchy endosperm © 2012 McGraw-Hill Higher Education. All rights reserved. 9 Glycemic Index and Glycemic Response Insulin and glucose levels Quick rise in glucose and insulin levels = high glycemic index ◦ Eating high glycemic index foods may increase appetite ◦ May increase risk of diabetes and heart disease ◦ Unrefined grains, fruits, vegetables and legumes – relatively low glycemic index © 2012 McGraw-Hill Higher Education. All rights reserved. 10 Recommended Carbohydrate Intake Average American consumes 200-300 grams 130 grams needed to meet the body’s requirements for essential carbohydrates Recommended: adults 45-65% of total daily calories (225-325 grams) WHO recommends a limit of 10% of total calories from added sugars USDA recommends about 8 teaspoons of sugar per day © 2012 McGraw-Hill Higher Education. All rights reserved. 11 Fiber – A Closer Look Food and Nutrition Board ◦ Dietary fiber: nondigestible carbohydrate that is present naturally ◦ Functional fiber: nondigestible carbohydrate that has been isolated or synthesized ◦ Total fiber is the sum of both ◦ Soluble (viscous) fiber ◦ Insoluble fiber Sources ◦ All plant substances Recommended intake ◦ 38 grams for adult men ◦ 25 grams for adult women ◦ Needs to come from foods, not supplements © 2012 McGraw-Hill Higher Education. All rights reserved. 12 Vitamins Organic (carbon-containing) substances required in small amounts to regulate various processes within a living cell 13 vitamins: ◦ 4 fat soluble: A, D, E, K ◦ 9 water soluble: C and 8 B-complex vitamins (thiamin (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), folate, B-12, biotin, pantothenic acid) Sources: ◦ Human body does not manufacture most vitamins ◦ Abundant in fruits, vegetables, grains © 2012 McGraw-Hill Higher Education. All rights reserved. 13 Minerals Inorganic micronutrients (do not contain carbon) Help to regulate body functions, aid growth, maintain body tissues, release energy 17 essential minerals ◦ Major minerals: 100+ milligrams per day Calcium, phosphorus, magnesium, sodium, potassium, chloride ◦ Trace minerals: minute amounts Copper, fluoride, iodide, iron, selenium, zinc © 2012 McGraw-Hill Higher Education. All rights reserved. 14 Water You are composed of about 50-60% water Can live up to 50 days without food, but only a few days without water Food and fluids you consume provide 80-90% of your daily water intake; the rest is through metabolism Food and Nutritional Board ◦ Men: 3.7 total liters of water, with 3.0 liters (13 cups) coming from beverages ◦ Women: 2.7 total liters of water, with 2.2 liters (9 cups) coming from beverages © 2012 McGraw-Hill Higher Education. All rights reserved. 15 Other Substances in Food Antioxidants ◦ React with free radicals ◦ Vitamin C, vitamin E, selenium, carotenoids Phytochemicals ◦ Soy foods may help lower cholesterol levels ◦ Cruciferous vegetables render some carcinogenic compounds harmless ◦ Allyl sulfides (garlic and onions) boost the cancerfighting immune cells © 2012 McGraw-Hill Higher Education. All rights reserved. 16 Nutritional Guidelines: Planning Your Diet Here are several tools to help you design a healthy diet: ◦ Dietary Reference Intakes ◦ Dietary Guidelines for Americans ◦ MyPyramid © 2012 McGraw-Hill Higher Education. All rights reserved. 17 Dietary Reference Intakes (DRIs) Food and Nutrition Board set standards RDAs (recommended daily allowance) AI (adequate intake) Include standards for both recommended and maximum safe intakes Established standards for nutrient intake Prevent nutrient deficiencies Promote health Daily Values used on food labels ◦ Based on 2,000 calorie diet © 2012 McGraw-Hill Higher Education. All rights reserved. 18 Dietary Guidelines for Americans Reduce overall calories Eat a variety of nutrient-dense foods Limit saturated fats to less than 7% of total calories Limit cholesterol to less than 300 mg per day Choose high-quality proteins Choose carbohydrates wisely Eat less sodium Eat more potassium Reduce or eliminate alcohol Follow food safety guidelines © 2012 McGraw-Hill Higher Education. All rights reserved. 19 Figure 12.3 Nutrient Density of 12-ounce Portions of Selected Beverages © 2012 McGraw-Hill Higher Education. All rights reserved. 20 USDA’s MyPyramid USDA released in 2005 Reminds consumers to make healthy food choices and to be active every day Key messages: Personalization Daily physical activity Moderation of food intake Proportionality Variety Gradual improvement © 2012 McGraw-Hill Higher Education. All rights reserved. 21 Figure 12.4 USDA’s MyPyramid © 2012 McGraw-Hill Higher Education. All rights reserved. 22 Figure 12.5 MyPyramid Food Intake Patterns © 2012 McGraw-Hill Higher Education. All rights reserved. 23 Table 12.6 MyPyramid Daily Calorie Intake Levels © 2012 McGraw-Hill Higher Education. All rights reserved. 24 MyPyramid: Number of Daily Servings and Serving Sizes Grains (6): 1 slice of bread, 1 small muffin (2.5” diameter), 1 cup ready-to-eat cereal flakes, ½ cup cooked cereal, 1 (6”) tortilla Vegetables (5): ½ cup cooked or raw vegetables, 1 cup raw leafy salad greens, ½ cup of vegetable juice Fruit (4): ½ cup fresh/canned/frozen fruit, ½ cup 100% fruit juice, 1 small whole fruit, ¼ cup dried fruit © 2012 McGraw-Hill Higher Education. All rights reserved. 25 MyPyramid: Number of Daily Servings and Serving Sizes Milk/Dairy (3): 1 cup milk or yogurt, ½ cup ricotta cheese, 1½ oz. natural cheese, 2 oz. processed cheese Meat and Beans (5½): 1 oz. cooked lean meat/poultry/fish, ¼ cup cooked dry beans or tofu, 1 egg, 1 tablespoon peanut butter, ½ oz. nuts or seeds Oils (6 teaspoons per day) Discretionary calories, solid fats, and added sugars © 2012 McGraw-Hill Higher Education. All rights reserved. 26 The Vegetarian Alternative Reasons Types: ◦ ◦ ◦ ◦ ◦ ◦ Vegans Lacto-vegetarians Lacto-ovo-vegetarians Partial vegetarians Semivegetarians Pescovegetarians ◦ ◦ ◦ ◦ ◦ Vitamin B-12 Vitamin D Calcium Iron Zinc A food plan for vegetarians © 2012 McGraw-Hill Higher Education. All rights reserved. 27 Functional Foods Foods to which health-promoting or disease-preventing components have been added Fortified, enriched, enhanced Examples Calcium-fortified orange juice Margarine enriched with sterols to lower the risk of heart disease Sports bars for energy Vitamin B-12 enriched soy milk © 2012 McGraw-Hill Higher Education. All rights reserved. 28 Dietary Challenges for Special Population Groups Children and teenagers College students Older adults Athletes People with special health concerns © 2012 McGraw-Hill Higher Education. All rights reserved. 29 A Personal Plan: Making Informed Choices About Food Reading food labels Reading dietary supplement labels Evaluating functional foods © 2012 McGraw-Hill Higher Education. All rights reserved. 30 Using Food Labels © 2012 McGraw-Hill Higher Education. All rights reserved. 31 Protecting Yourself Against Foodborne Illness Causes of foodborne illnesses: ◦ ◦ ◦ ◦ ◦ ◦ ◦ ◦ Campylobacter jejuni Salmonella Shigella Escherichia coli Listeria monocytogenes Staphylococcus aureus Clostridium botulinum Norovirus Preventing and treating foodborne illnesses © 2012 McGraw-Hill Higher Education. All rights reserved. 32 Environmental Contaminants and Organic Foods Organic foods ◦ Concerned about pesticides and other environmental contaminants ◦ Must meet strict USDA guidelines Guidelines for fish consumption ◦ Do not eat shark, swordfish, king mackerel, or tilefish ◦ Eat up to 12 oz. a week of a variety of fish and shellfish that is lower in mercury ◦ Limit albacore tuna to 6 oz. per week ◦ Check advisories about the safety of recreationally caught fish © 2012 McGraw-Hill Higher Education. All rights reserved. 33 Additives in Food Some 2,800 substances are added to foods to maintain or improve nutritional quality, freshness, to help in processing or preparation, or to alter taste or appearance Most common: sugar, salt, corn syrup, citric acid, baking soda, vegetable colors, mustard, pepper Potential health concerns: Nitrates and nitrites BHA and BHT Sulfites Monosodium glutamate (MSG) © 2012 McGraw-Hill Higher Education. All rights reserved. 34 Food Biotechnology Used to produce specific desired traits in plants, animals, or microorganisms Food irradiation Genetically modified foods (GM) Alters characteristics of a plant, animal, or microorganism through gene manipulation Animal cloning Kills potentially harmful pathogens FDA deems safe for human consumption, but probably will be used as breeding stock Labeling of GM foods FDA does not require special labeling for GM foods © 2012 McGraw-Hill Higher Education. All rights reserved. 35 Food Allergies and Food Intolerances Food allergies ◦ ◦ ◦ ◦ Reaction of the body’s immune system Affect 1.5% of the adult population Affect up to 6% of infants 90% of food allergies Cow’s milk, eggs, peanuts, tree nuts, soy, wheat, fish, shellfish Food intolerances ◦ Problem lies with metabolism rather than with the immune system © 2012 McGraw-Hill Higher Education. All rights reserved. 36 Nutrition Basics Chapter 12 © 2012 McGraw-Hill Higher Education. All rights reserved.