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Chapter 7 Nutrition Your Responsibility • Did you read the assigned chapter before coming to class? • Did you make appropriate notes? • Did you try the Assess Your Knowledge at the beginning of the chapter and the Vocabulary Challenge at the end? Student Learning Outcomes Student Self-Assessment • Can you list the six major nutrients and state their purposes? • Do you know the major differences between the USDA ChooseMyPlate, the Harvard Healthy Eating Pyramid, and the Mediterranean Pyramid? • Do you know what conditions, rules, or laws organic foods must follow? • Do you know the difference between food allergies and food intolerances? Elements of Nutrition The Digestive Process • Digestion begins in the mouth, where food is broken down and then passed into the gastrointestinal tract. • The stomach releases gastric enzymes that turn food into a liquid called chyme. • About 20 percent of food is released into the bloodstream from the stomach. • The small intestine does the bulk of the digestive work. • Undigested chyme enters the large intestine, where it is processed for excretion. The Digestive System Energy in Food A calorie is a measure of the energy a food contains. • Fats provide 9 calories per gram. • Carbohydrates provide 4 calories per gram. • Proteins provide 4 calories per gram. • Alcohol provides 7 calories per gram. Carbohydrates • The body’s preferred energy source. • Are found in all grains, grain products, legumes, nuts, all fruits and vegetables. • Excess carbohydrates can be stored in the liver and muscle as glycogen. • Recommended intake of carbohydrate is from 45–65 percent of total calories. • Carbohydrates are classified as either simple or complex. Simple Carbohydrates • Simple carbohydrates are either monosaccharides or disaccharides. • They are quickly digested and can raise blood sugar levels quickly. • Simple carbohydrates are found in sodas, jams, jellies, candy, and sugar. • Fruits, fruit juices, and milk are primarily simple carbohydrates, but unlike the others, these do supply vitamins, minerals, and may contain protein and fiber. Complex Carbohydrates • These are polysaccharides. • They take longer to digest and do not raise blood sugar levels quickly. • Examples include cereals, rice, breads, pasta, and some vegetables and fruits. • Complex carbohydrates also contain vitamins, minerals, and sometimes fiber and protein. Complex Carbohydrates–Either Whole Grain or Refined Grains • Whole grain complex carbohydrates contain all parts of the grain kernel, including the bran layer, the endosperm, and the germ. • As a result, they naturally contain fiber, B and E vitamins, minerals, phytonutrients, and a small amount of unsaturated fat. • Refined grains are made when the bran, endosperm, and germ are separated. The endosperm is used to make flour, but its nutritional value is now reduced by between 25 and 90 percent. The government mandates that it must be “enriched” to a specific level that is still lower than nutrients contained in the whole grain. The Glycemic Index • Carbohydrates cause blood sugar to rise to provide necessary energy. • The effect a food has to raise blood glucose is measured by the glycemic index. • People with health concerns might find the glycemic index helpful in controlling blood sugar levels. Fiber • Fiber is a non-digestible form of carbohydrate. • Dietary fiber occurs naturally in food, while functional fiber is either synthesized or extracted from a food source. • Fiber is essential to health, and recommendations are that adult males need about 38 grams of fiber each day, and adult females about 25 grams of fiber each day. • Fiber is found in whole grains, vegetables, fruits, legumes, nuts, and beans. MENTAL BREAK • Why are athletes given fruit juice and sugarcontaining beverages during breaks? Proteins • Proteins are made up amino acids. Some are essential and must be consumed, while the body can make other amino acids. • A protein that contains all 8 essential amino acids is known as a complete protein. Meat, chicken, fish, milk, cheese are all complete proteins. • A protein that does not contain all 8 essential amino acids is known as an incomplete protein. • Combining different incomplete proteins can provide all the essential amino acids. Recommended Intake of Proteins • Adults need a minimum of 0.8 grams of protein per kilogram of body weight. • For a person weighing about 160 pounds, this becomes about 64 grams of protein. • Most Americans eat more than enough protein, and excess cannot be stored. • Excess protein may be harmful to health. • Proteins are needed to build and repair cell tissue and provide some energy. High Protein Diets • High-protein diets usually eliminate or reduce carbohydrates. • This may result in weight loss. • Over the short term, high protein diets are probably not harmful, but if maintained, may increase the risk for coronary heart disease, and renal, bone, and liver abnormalities. • In a high-protein diet, the body may resort to fat for energy. When the body breaks down fat, ketones are released. In extreme situations, ketoacidosis might occur, which can lead to coma and even death. Fats (lipids) • Fats are necessary for healthy skin, hair, insulating organs, maintaining body temperature, and are used in cellular functions. • Moderate consumption is essential for health, but over-consumption is harmful. • When too many fat calories are consumed, the excess is converted into triglycerides. • Less than 30 percent of total calories should come from fat. • Fats are either saturated, polyunsaturated, or monounsaturated. Saturated Fats • Saturated fats are found in tropical oils such as palm and coconut oils, and in all animal source foods. • The chemical structure of a saturated fat is fully saturated with hydrogen atoms, and does not contain double bonds between carbon atoms. This makes most saturated fat hard at room temperature. • This type of fat has been shown to increase the risk of coronary diseases, cancers, diabetes, obesity, and contribute to high cholesterol levels. • Less than ten percent of total fat should be in the form of saturated fat. Unsaturated Fats (polyunsaturated and monounsaturated) • Unsaturated fats come from plant sources. • They contain far less hydrogen than saturated fats. • They differ from saturated fats in that their chemical structure contains double bonds. • Monounsaturated fats contain only on double-bonded carbon atom, while polyunsaturated fats contain more than one double bond. • Corn, safflower, sesame, soybean, and sunflower oils are high in polyunsaturated fat, while canola, olive, avocado, and peanut oils are high in monounsaturated oil. Trans Fatty Acids (TFAs) • TFAs are found in small quantities in beef, pork, and the butterfat in milk and butter. • They are also formed when liquid unsaturated oil is partially hydrogenated to make shortening, margarine, or cooking oil. • Partially hydrogenated oils provide about 75 percent of the TFA in the US Diet. • They increase risk for coronary artery disease and high blood cholesterol. Microelements of Nutrition • Vitamins • Minerals • Antioxidants • Phytonutrients Do You Need a Multivitamin? • In 2003, the Annals of Internal Medicine published a study that demonstrated a lack of infection risk benefit provided by taking multivitamins in the general populations, but subjects with diabetes did experience fewer infections. • The strength of the evidence currently available does not show that taking a multivitamin prevents cancer, cardiovascular disease, hypertension, cataracts, or agerelated degeneration. • Although there is little evidence to show that taking multivitamins has a positive impact on health in the general population, certain populations (those undernourished or those with diabetes) may experience a benefit. Guidelines for Healthy Eating • 2010 Dietary Guidelines for Americans • Daily Reference Intakes • Daily Recommended Values Healthy Dietary Plans • • • • The USDA ChooseMyPlate The Harvard Healthy Eating Pyramid The Mediterranean Pyramid The Vegetarian Diet Pyramid 1. 2. 3. 4. Balance calories. Enjoy your food, but eat less. Avoid oversized portions. Eat more vegetables, fruits, whole grains, and fat-free or 1% milk and dairy products. 5. Make half your plate fruits and vegetables. 6. Switch to fat-free and low-fat (1%) milk. 7. Make half your grains whole grains. 8. Cut back on foods high in solid fats, added sugars and salt. 9. Compare sodium in foods. 10. Drink water instead of sugary drinks. * Abstracted from ChooseMyPlate, “10 Tips to a Great Plate” (http://www.choosemyplate.gov/healthy-eating-tips/ten-tips.html) Consumer Issues in Nutrition • • • • • Organic Foods Genetically Modified Foods Irradiated Foods Food Allergies Food Intolerances Choosing a Diet Based on Health Decisions Responsibility and Accountability Responsibility • Taking responsibility for your nutrition requires that you are informed and use this information to make better food choices. • Making the right choices and planning can lead to a more nutritious and less harmful diet. Accountability • You may be aware of your own accountability for poor nutritional choices now. Perhaps you are overweight, often tired, or unable to exercise as you might like. • Making healthier choices more frequently than unhealthy choices is a step in the right direction.