Objectives Define nutrition and describe its relationship to health and well- being. Learn to use the USDA MyPyramid guidelines for healthier eating. Describe the functions of the nutrients – carbohydrates, fiber, fats, proteins, vitamins, minerals, and water – in the human body. Define the various energy production mechanisms of the human body. Be able to conduct a comprehensive nutrient analysis and implement changes to meet the Dietary Reference Intakes (DRIs). Identify myths and fallacies regarding nutrition. Become aware of guidelines for nutrient supplementation. Learn the 2005 Dietary Guidelines for Americans. Analyze your diet and plan for healthy nutrition.
Introduction Proper nutrition is essential to overall health Having good nutrition: Means that a persons diet supplies the essential nutrients needed to carry out normal tissue growth and repair. Supplies enough substrates to fuel all body processes. ChooseMyPlate.gov provides nutrition guidelines and recommended daily food amounts according to various caloric requirements.
Introduction Nutrients should be obtained from a wide variety of sources. U.S. diet Too high in calories, sugar, saturated fat, trans fat, sodium Too low in grains, fruits, vegetables Diet and nutrition play a role in the development and progression of heart disease, cancer, obesity, diabetes, and osteoporosis
Nutrients Six essential nutrients Fuel Nutrients needed for energy: carbohydrates, fats, and proteins. Regulatory nutrients necessary to function normally with no caloric value: vitamins, minerals, water, and fiber. Macronutrients needed in proportionally large amounts daily: carbohydrates, fats, proteins, and water. Micronutrients required in small amounts daily: vitamins and minerals.
Nutrients Nutrient Density Foods packed with nutrients but with low or moderate calories are classified as having high nutrient density. Calorie: The simplified term for a kilocalorie (kcal), the amount of heat necessary to raise the temperature of 1 kilogram of water 1 degree Centigrade.
Carbohydrates Major source of energy (4 calories/gram) Regulate fat and metabolize protein Major sources are breads, cereals, fruits, vegetables, milk/dairy products Two types: Simple Complex
Simple Carbohydrates Often called “sugars,” which have little nutritive value Examples are candy, soda, and cakes Divided into monosaccharides and disaccharides Monosaccharides: glucose, fructose, galactose Disaccharides: sucrose, lactose, maltose
Complex Carbohydrates Also referred to as “polysaccharides” Carbohydrates formed by ten or more monosaccharide molecules linked together Starches Storage form of glucose in plants Dextrins Formed from the breakdown of starches exposed to dry heat Glycogen Storage form of glucose
Fiber Form of complex carbohydrates Present mainly in plant leaves, skins, roots, and seeds Processing and refining foods removes most of their natural fiber Dietary sources include Whole-grain cereals and breads Fruits and vegetables Legumes
Fiber Soluble fiber Dissolves in water to form gel-like substance that encloses food particles Helps decrease blood cholesterol and blood sugar levels Oats, fruits, barley, legumes, psyllium Insoluble fiber Not easily dissolved in water but binds with water Causes a softer and bulkier stool Speeds passage of food residues through intestines Wheat, cereals, vegetables, skins of fruits Most common types of fiber are: Cellulose, Hemicellulose, Pectins, Gums and Mucilages
High-fiber foods are essential in a healthy diet Age 50 and under Women = 25 g/day Men = 38 g/day Over age 50 Women = 21 g/day Men = 30 g/day Current average daily U.S. intake About 15 g/day
Fat Also called lipids Most concentrated source of energy (9 cal/gram) Need fat for: Part of cell structure Stored energy Insulator for body heat preservation Shock absorption Supplies essential fatty acids Carries fat-soluble vitamins (A, D, E, K)
Major types of fats (lipids) Simple Fats Over 90% of the weight of fat in foods and over 95% of the fat stored in the body are in the form of triglycerides Saturated fats are mainly of animal origin Unsaturated are found mostly in plant products Further classified into monounsaturated and polyunsaturated fatty acids
Chemical structure of saturated and unsaturated fatsSaturated Fats Meats, animal fat, lard, whole milk, cream, butter, cheese, ice cream, hydrogenated oils, coconut oil, and palm oils Usually do not melt at room temperature Coconut oil and palm oils are exceptions Raise blood cholesterol level
Unsaturated Fats Usually liquid at room temperature Help lower blood cholesterol Monounsaturated fats (MUFAS) found in olive, canola, peanut, sesame oils, avocados, cashews, and peanuts Polyunsaturated fats (PUFAS) found in corn, cottonseed, safflower, walnut, sunflower, soybean oils, and fish, almonds, pecans
Fats (Lipids) Trans fatty acids The result of partial hydrogenation to increase shelf life. Provide no known health benefit. The words "partially hydrogenated" and "trans fatty acids" indicate that the product carries a health risk just as high as or higher than that of saturated fat. Found in Margarine and spreads, shortening, some nut butters, crackers, cookies, dairy products, meats, processed foods, and fast foods
Fats (Lipids) Polyunsaturated omega fatty acids Essential to human health and have to be consumed in the diet. Omega-3 fatty acids Polyunsaturated fatty acids found primarily in cold-water seafood and flaxseeds thought to lower blood cholesterol and triglycerides Three major types of omega-3 fatty acids: EPA, DHA, and ALA protect against irregular heartbeats and blood clots, reduce triglycerides and blood pressure, and defend against inflammation. Omega-6 fatty acids LA, GLA, and AA Excessive intake tends to contribute to inflammation – 4 to 1 ratio recommended
Fats (Lipids) The canning process for fish destroys most of the omega-3 fatty acids Good sources of omega- 3 ALA include flaxseeds, canola oil, walnuts, wheat germ, and green leafy vegetables
Fats (Lipids) Compound fats Lipoproteins transport fats in the blood and play a large role in heart disease Major forms are HDL, LDL, VLDL Derived fats Sterols Found in food and manufactured in the body primarily from saturated and trans fats
Proteins Needed for: Build and repair tissue Part of hormones, antibodies, and enzymes (formed by proteins) Necessary for normal functioning Help maintain normal body fluid balance Source of energy (4 calories/gram) if carbohydrate is insufficient Sources are meats and alternatives, milk, and other dairy products Excess proteins can be converted to glucose or fat, or excreted in urine Daily consumption of beef, poultry, or fish should be limited to 3 ounces to 6 ounces.
Amino Acids The body uses 20 amino acids to form different types of protein 9 amino acids are termed “essential” because the body cannot produce them 11 amino acids are termed “nonessential” because the body can produce them if food proteins in the diet provide adequate nitrogen All amino acids must be present in the diet for the body to function normally
Vitamins Organic nutrients essential for normal metabolism, growth, and development Classified according to solubility Fat soluble (A, D, E, and K) Water soluble (B complex and C) Most vitamins must be obtained through diet A, D, and K are formed in the body C, E, and beta-carotene are “antioxidants”
Minerals Inorganic nutrients essential for normal body functions Part of all cells Help maintain water balance and acid-base balance Essential components of enzymes Regulate muscular and nervous tissue impulses, blood clotting, normal heart rhythms
Water Most important nutrient Studies show people are getting enough water from the liquids and the moisture content of solid foods. To avoid dehydration, use the thirst signal Exception is exercise
Balancing the American Diet National Academy of Sciences created guidelines for a well- balanced diet The ranges allow for flexibility in planning diets for individual health and physical activity needs The source of fat calories is critical
Nutrition Standards Dietary Reference Intakes (DRIs) A general term that describes four types of nutrient standards that establish adequate amounts and maximum safe nutrient intakes in the diet (Table 3.7) Estimated Average Requirements (EAR) Recommended Dietary Allowances (RDA) Adequate Intakes (AI) Tolerable Upper Intake Levels (UL)
Nutrition Standards Estimated Average Requirements (EAR): The amount of a nutrient that meets the dietary needs of half the people in the U.S. Recommended Dietary Allowances (RDA): The daily amount of a nutrient (statistically determined from the EARs) considered adequate to meet the known nutrient needs of almost 98% of all healthy people in the U.S. Adequate Intakes (AI): The recommended amount of a nutrient intake when sufficient evidence is not available to calculate the EAR and subsequent RDA Tolerable Upper Intake Level (UL) establishes the highest level of nutrient intake that appears safe for most healthy people (Table 3.8)
Nutrition Standards Daily Values (DVs) reference values for nutrients and food components for use on food labels (Figure 3.6) Include fat, saturated fat, and carbohydrates (as a percent of total calories); cholesterol, sodium, and potassium (in milligrams); and fiber and protein (in grams). Expressed as percentages for a 2,000-calorie diet.
Nutrient Analysis Keep a 3-day record of all foods and beverages consumed Includes measurements of calories, carbohydrates, fats, protein, cholesterol, sodium, vitamins, and minerals. Use the food tracker on choosemyplate.gov
Nutrient Analysis Most revealing information learned in a nutrient analysis is the source of fat intake Average daily fat consumption in the U.S. diet About 34% of the total caloric intake Much of it from saturated fat and trans fatty acids, which increase the risk for chronic diseases
Achieving a Balanced DietA well-balanced diet entails eating a variety ofnutrient dense foods and monitoring total dailycaloric intake.Eat from all food groups Whole grains, vegetables, fruits, and milk provide nutritional base Meats and beans group Oils sparingly and avoid trans fats
Phytonutrients Fruits and vegetables are the sole source of phytonutrients Show promising results in the fight against cancer and heart disease They seem to have a powerful ability to block the formation of cancerous tumors They may reduce inflammation, inhibit blood clots, and prevent LDL cholesterol oxidation to fight heart disease
Choosing Healthy Foods Learn the nutritive value of typical foods you eat by reading food labels Be aware that there is label misinformation as the FDA does not have the manpower to regularly check food labels Healthy eating requires proper meal planning and adequate coping strategies
Vegetarianism Vegetarian diets can meet the Dietary Guidelines for Americans and the DRIs for nutrients Vegans eat no animal products at all. Ovovegetarians allow eggs in the diet. Lactovegetarians allow foods from the milk group. Ovolactovegetarians include egg and milk products in the diet. Semivegetarians do not eat red meat, but do include fish and poultry in addition to milk products and eggs in the diet
Vegetarianism Nutrient concerns Strict vegans need B12 supplements Eat foods that possess complementary proteins Vegetarian diets may also lack vitamin D, riboflavin, calcium, iron, zinc But can be found in certain foods
Nuts and Soy Products Nuts Although nuts are 70 to 90 percent fat, most of this is unsaturated fat. Supply vitamin E and folic acid, B vitamins, calcium, copper, potassium, magnesium, fiber, and phytonutrients. Should be avoided as a snack because they are high in calories. Soy products Rich in plant protein, unsaturated fat, and fiber; some soy is high in calcium. Contain plant chemicals, isoflavones, that act as antioxidants and may protect against estrogen-related cancers Do not exceed 3 servings of soy per day
Probiotics Healthy bacteria (abundant in yogurt) that help break down foods and prevent disease- causing organisms from settling in the intestines Select yogurt with L-acidophilus, Bifidus, and inulin Avoid yogurt with added fruit jam, sugar, and candy
Advanced Glycation End Products (AGEs) Compounds implicated in aging and chronic diseases via increased body structure oxidation and inflammation. Contribute to the development of atherosclerosis, diabetes, kidney disease, osteoarthritis, rheumatoid arthritis, Alzheimer’s disease, and heart disease. Found in foods that are cooked in dry heat at high temperatures, processed, and high in fat content. Broiling, grilling, and frying produce these AGEs. Not as much AGEs are found from braising, steaming, stewing, roasting, boiling, and poaching forms of cooking French fries have 8 time the amount of baked potatos
Diets from Other Cultures Mediterraneans have lower rates of diet-linked diseases and a longer life expectancy Diet features olive oil, whole grains, fruits, vegetables, legumes, fish, red wine, nuts and dairy products in moderation Although a semivegetarian diet, up to 40% of the daily caloric intake comes from fat: mostly monounsaturated fat from olive oil
Diets from Other Cultures Ethnic diets Many are healthier than the typical American diet because they emphasize complex carbohydrates and limit fat intake. Unfortunately, the generally healthier ethnic diets quickly become Americanized when these groups adapt to the United States. Common characteristics High in fruits, vegetables, and grains. Low in fat and saturated fat. Use low-fat or fat-free dairy products. Emphasize portion control—essential in a healthy diet plan.
Nutrient Supplementation Nutrient requirements can be met using MyPyramid and as few as 1,500 calories of food. Supplement doses should not exceed the ULs Supplements may help a small group of individuals; most supplements do not provide benefits to healthy people who eat a balanced diet.
Nutrient Supplements Water-soluble vitamins: The body cannot retain these vitamins as long as fat-soluble vitamins; excessive intake is excreted Small amounts, however, can be retained for weeks or months Fat-soluble vitamins: stored in fatty tissue; daily intake of these vitamins is not as crucial
Antioxidants Oxygen is used to change carbohydrates and fats into energy A small amount of oxygen ends up in an unstable form, referred to as oxygen free radicals A free radical molecule has a normal proton nucleus with a single, unpaired electron (making it extremely reactive)
Antioxidants Free radicals attack and damage proteins, lipids, cell membranes, and DNA Free radical formation is enhanced by solar radiation, cigarette smoke, air pollution, radiation, some drugs, injury or infection, chemicals (such as pesticides), and other environmental factors
Antioxidants Vitamin E Found in oil-rich seeds and vegetable oils Supplements should be taken with a meal that contains some fat as vitamin E is fat soluble RDA is 15 mg Almonds, hazelnuts, peanuts, canola oil, safflower oil, cottonseed oil, kale, sunflower seeds, shrimp, wheat germ, sweet potato, avocado, and tomato sauce Vitamin C May offer benefits against heart disease, cancer, and cataracts Body eliminates it in about 12 hours Consume vitamin C-rich foods twice a day for best results Body absorbs little vitamin C beyond the first 200 mg Oranges, citrus fruit, bell peppers, kale, cauliflower, tomatoes, strawberries
Antioxidants Beta-carotene Recommended dose is 20,000 IU from food sources Research found supplements do not offer protection against heart disease, cancer, nor offer other benefits One medium raw carrot provides about 20,000 IU Can be obtained from sweet potatoes, pumpkin, cantaloupe, squash, kale, broccoli, tomatoes, peaches, apricots Selenium 200 micrograms (mcg) of selenium daily decreases risk of Prostate cancer by 63% Colorectal cancer by 58% Lung cancer by 46% Also breast, liver, and digestive tract cancers One Brazil nut (unshelled) provides 100 mcg Shelled nuts average only about 20 mcg
Top antioxidant foods Fruits and vegetables are the richest sources of antioxidants and phytonutrients
Nutrient Supplementation A multivitamin complex that provides 100% of the DV for most nutrients can help fill deficiencies There is no solid scientific evidence that multivitamins decrease the risk for cardiovascular disease and cancer Multivitamins don’t provide energy, fiber, phytonutrients
Benefits of Foods Choosing a wide variety of food is the best strategy to gain nutritional benefits. Supplements do not supply all of the nutrients and other beneficial substances present in food and needed for good health. Wholesome foods contain vitamins, minerals, carbohydrates, fiber, proteins, fats, phytochemicals, and other substances not yet discovered. Many nutrients work in synergy, enhancing chemical processes in the body.
Functional Foods Foods or food ingredients that offer specific health benefits beyond those supplied by the traditional nutrients they contain. A tomato is a functional food because it contains the phytochemical lycopene thought to reduce prostate cancer risk. Some manufacturers are creating "functional foods" by adding an ingredient to enhance market appeal. May undermine good nutrition because of their extra calories, sugar, salt, and/or fat
Genetically Modified Crops Genetically modified organism (GMO) benefits: Resist disease and extreme environmental conditions better. Require less fertilizers and pesticides. Last longer. Have better nutrient content and taste. Save billions of dollars and help feed the hungry. Debate over GM foods Genetic modifications create new "transgenic" organisms that have potentially unpredictable effects on the environment and on humans. Illnesses or allergies in humans; destruction of other plants or herbicide- resistant "superweeds" may emerge. Avoiding GM foods Buy organic foods; organic trade organizations will not certify GM foods. Buy from local markets; small farmers are less likely to use this technology.
Energy Substrates for Physical Activity Two main fuels Glucose derived from foods is stored as glycogen in muscles and the liver. Fatty acids, the product of the breakdown of fats, stored as fat in the body Amino acids from proteins are used as an energy substrate when glucose is low.
Energy Substrates for Physical Activity ATP can be resynthesized in three ways: ATP-CP (high-energy phosphate compound) stored in the body to use during all-out activities lasting 1-10 seconds Anaerobic/lactic acid system breaks down glucose to create ATP without oxygen for maximal-intensity exercise sustained for 10 seconds to 3 minutes Aerobic system produces ATP using glucose, fatty acids, and oxygen for steady-state exercise
Nutrition for Athletes During rest, fat supplies about 2/3 of the energy needs. During exercise, both glucose (glycogen) and fat supply the energy. Generally, athletes do not require special supplementation or diet. Athletes need more calories daily and more carbohydrate intake during prolonged physical activity.
Nutrition for Athletes Carbohydrate loading Normal levels of glycogen storage: 1,500–2,000 calories. About 75 percent in muscle tissue. Can be increased greatly through carbohydrate loading. Following an exhaustive workout: Eat a combination of carbohydrates and protein within 30 minutes of exercise to speed up glycogen storage. Protein intake increases insulin activity, thereby enhancing glycogen replenishment. A 70 percent carbohydrate intake then should be maintained throughout the rest of the day.
Nutrition for Athletes Hyponatremia In some cases, athletes participating in long or ultra long-distance races may suffer from hyponatremia or low sodium concentration in the blood Use sports drinks that contain sodium to replace electrolytes lost in sweat and prevent blood sodium dilution.
Nutrition for Athletes Creatine supplementation Creatine is an organic compound derived primarily from meat and fish Creatine combines with inorganic phosphate and forms the high-energy compound CP that is used by cells to resynthesize ATP during all-out activities of very short duration. Supplementation can result in an approximate 20 percent increase in the amount of creatine that is stored in muscles. Endurance competitors benefit little because of low reliance on CP energy.
Bone Health and Osteoporosis A condition that leads to softening, deterioration, or loss of bone mineral density Causes disability, fractures, and even death from medical complications About 22 million women in the U.S. suffer from this condition (16 million do not know they have it) One in 2 women and one in 8 men will suffer from osteoporosis
Threats to Bone Health (Osteoporosis) Maximize bone density during youth Maintain adequate calcium intake Lifetime program of physical activity Do not smoke Avoid excessive use of alcohol, soft drinks, coffee Avoid corticosteroid drug use Avoid high-protein diet
Bone Health and Osteoporosis Bone density can be promoted early in life by making sure the diet has sufficient calcium and participating in weight- bearing activities If you dont get enough (most people dont), take calcium supplements. RDA for calcium is 1,000- 1,300 mg per day RDA can be met by a diet high in calcium-rich foods
Hormone-Replacement Therapy The most common treatment to prevent bone loss following menopause for decades, but a large study was terminated 3 years early due to increased risk for breast cancer, blood clots, stroke, and heart attack. HRT may still be the most effective treatment to relieve acute (short-term) symptoms of menopause. Medications Fosamax (alendronate) and Actonel (risedronate) prevent bone loss and, furthermore, actually help increase bone mass.
Iron Deficiency Key element of hemoglobin in blood RDA for adult women is 15-18 mg per day RDA for adult men is 8-11 mg per day Depletion of iron stores leads to anemia (hemoglobin concentration in red blood cells is too low) Heavy training increases iron requirement Iron-rich foods should be included in the diet
2005 Dietary Guidelines for Americans Recommendations for general public age 2 years and older Description of healthy diet Fruits, vegetables, whole grains, and milk products Lean meats, poultry, fish, beans, eggs, and nuts Low in fats, cholesterol, salt, and sugar
2005 Dietary Guidelines for Americans1. Consume a variety of foods2. Control calorie intake3. Be physically active4. Increase intake of fruits, vegetables, whole grains, and milk products5. Choose fats wisely6. Choose carbohydrates wisely7. Choose and prepare foods with little salt8. If you drink alcohol, do so in moderation9. Keep food safe to eat Behaviors to prevent foodborne illness
Real Life Stories Critical Thinking Questions 1. Are there similarities/differences between Kwame’s pre-Fitness and Wellness course nutrition habits and your current eating patterns? How were his eating habits affecting his overall health and quality of life? 2. Discuss ways in which you can plan ahead to maintain healthy behaviors prior to attending a social gathering that includes food and alcohol consumption? 3. Many people like Kwame regularly consume fast foods. What wise/healthy food choices can you make when you are on the go or are unable to prepare your own meals?
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