Fats Essential in Small Amounts Fats supply energy, insulate the body, support & cushion organs, absorb fat-soluble vitamins, add flavor & texture to

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1 Nutritional Requirements: Components of a Healthy Diet Nutrition 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 Sources of Energy in the Diet 3 classes of essential nutrients supply energy Fats CHO s Protein 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 Complete & Incomplete PRO Complete PRO sources foods that supply all the essential AAs in adequate amounts Meat, fish, poultry, eggs, milk, cheese, & soy Incomplete PRO sources foods that supply most but not all essential AAs Plants, including legumes, grains, & nuts Recommended PRO Intake Adequate daily intake of PRO 0.8 gram per kilogram (0.36 gram per pound) of body weight Acceptable Macronutrient Distribution Range 10 35% of total daily calories as PRO 1

2 Fats Essential in Small Amounts Fats supply energy, insulate the body, support & cushion organs, absorb fat-soluble vitamins, add flavor & texture to foods Essential fats (linoleic acid & alpha-linolenic linolenic acid) are key regulators of body process such as the maintenance of bld pressure & the progress of a healthy pregnancy Trans Fatty Acids The process of hydrogenation, in which hydrogen s are added to unsaturated fats, produces a mixture of saturated fatty acids & standard & trans forms of unsaturated fatty acids Trans fatty acids have an atypical shape that affects their chemical activity Total Fat Content of Foods What is the bottom LINE? Fats & Health Fats affect bld cholesterol levels Low-density lipoprotein (LDL) = BAD cholesterol High-density lipoprotein (HDL) = GOOD cholesterol Saturated & trans fats raise levels of LDL; trans fats also lower levels of HDL Unsaturated fats lower levels of LDL Fats & Health Fats & Health Fats also affect triglyceride levels, inflammation, heart rhythm, bld pressure, & cancer risk Best choices monounsaturated fats & polyunsaturated omega-3 fats Limit intake of saturated & trans fats 2

3 Carbohydrates An Ideal Source of Energy The primary function of dietary CHO is to supply energy to body cells. Some cells, such as those in the brain, nervous system, & bld, use only CHO s for fuel During high-intensity intensity exercise, muscles get most of their energy from CHO s During digestion, CHO s are broken into glucose for absorption; the liver & muscles take up glucose & store it in the form of glycogen Simple & Complex CHO s Simple CHO s contain 1 or 2 sugar units in each molecule Found naturally in fruits & milk and added to many other foods Include sucrose, fructose, maltose, & lactose Complex CHO s consist of chains of many sugar molecules Found in plants, especially grains, & legumes Include starches & most types of dietary fiber Refined CHO s vs. Whole Grains Whole grains are higher than refined CHO s Fiber Vitamins Minerals Whole grains take longer to digest 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. Recommended CHO Intake Adequate daily intake of CHO = 130 grams Acceptable Macronutrient Distribution Range 45 65% of total daily calories as CHO Limit on intake of added sugars Food & Nutrition Board: 25% or less of total daily calories World Health Organization: 10% or less of total daily calories Acceptable Macronutrient Distribution Ranges: Summary Protein 10 35% of total daily calories Fat 20 35% of total daily calories CHO 45 65% of total daily calories 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 & wheat bran 3

4 Recommended Intake of Fiber Women = 25 grams/day Men = 38 grams/day Americans currently consume about half this amount Vitamins Organic Micronutrients Vitamins organic substances needed in small amounts to help promote & regulate chemical reactions & processes in body cells 4 fat-soluble vitamins: A, D, E, & K Vitamins Vitamins are abundant in fruits, vegetables, & grains; they are also added to some processed foods If you consume too much or too little of a particular vitamin, i characteristic ti 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 compounds needed in small amounts for regulation, growth, & maintenance of body tissues & functions There are about 17 essential minerals: Major minerals (those that the body needs in amounts exceeding 100 mg/day) include: calcium, phosphorus, magnesium, sodium, potassium, & chloride Essential trace minerals include: copper, fluoride, iodide, iron, selenium, & zinc 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 & bone mineral loss Water A Vital Component Human body is composed of about 60-70% water Foods & 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/day Men need to drink about 13 cups of fluid/day Drink in response to thirst consume additional fluids for heavy exercise 4

5 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 The USDA Food Guide Pyramid Suggests a range of servings for 5 major food groups Smaller # of servings are for those who consume about 1600 calories a day Larger # of servings are for those who consume about 2800 calories a day Keys are to choose a variety of foods w/n each group and to focus on nutrient density The Food Guide Pyramid: A Guide to Daily Food Choices 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? 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 w/ certain special health concerns 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 calorie diet 5

6 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 The current American diet includes too many foods from the tip of the Pyramid (fats and sweets) & too many foods low in nutrients The current American diet is low in fruits, vegetables, whole grains, dietary fiber, & certain vitamins & minerals 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 Foods contributing to energy intake in the U.S.: Data from NHANES III and NHANES Journal of Food Composition and Analysis 17: Dietary Challenges for Special Population Groups Women nutrient nutrient density, calcium, iron Men fruits, vegetables, grains College students overall quality of food choices Older adults nutrient density, fiber, vitamin B-12 People w/ special health concerns discuss w/ physician or dietitian Dietary Challenges for Special Population Groups: Athletes Energy intake adequate 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 minutes during exercise Replace fluids after event (check body weight) Nutritional Planning: Making Informed Choices About Food Food labels Dietary supplement labels Food additives Foodborne illness 6

7 Food Labels Read labels to learn more about your food choices. 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 7