Chapter 8

1. Chapter 8 Nutrition:Eating for Optimum Health

2. Objectives • Examine the factors that influence dietary choices. • Discuss how to change old eating habits, including how to use MyPyramid. • Summarize the major essential nutrients. • Discuss food as a form of medicine and the facts related to new trends in nutrition. • Distinguish among the various forms of vegetarianism. • Discuss issues surrounding gender, exercise, and nutrition. • Discuss how unique situations in your life can influence dietary needs. • Discuss the unique problems college students face when trying to eat healthy foods. • Explain food safety concerns facing Americans and people in other regions of the world.

3. Assessing Eating Behaviors • Hunger – lack or shortage of basic foods needed to provide the energy and nutrients that supports health • Appetite – a learned desire to eat that may or may not have anything to do with feeling hungry • We eat for many reasons that have nothing to do with being hungry.

4. Cultural and social meanings attached to food Convenience Habit or custom Advertising Availability Economy Emotional comfort Weight/body image Social interaction Regional/seasonal trends Nutritional value Environmental conditions Eating Influences

5. Eating For Health • Nutrition – the science that investigates the relationship between physiological function and the essential elements of the foods we eat • Nutrients – the constituents of food that sustain humans physiologically: proteins, carbohydrates, fats, vitamins, minerals and water. • Calorie – a unit of measurement that indicates the amount of energy obtained from a particular food

6. Eating For Health • Nutrients and calories from: • Proteins • Fats • Carbohydrates • Vitamins • Minerals • Water

7. Eating For Health • Adequate: provides enough energy, nutrients and fiber to maintain health • Moderate: portion control, awareness of the amount of nutrients • Balanced: proper combinations of food groups • Varied: different colors mean you’re getting better coverage of vitamins and minerals • Americans typically get 38% of their calories from fat, 15% from proteins, 22% from complex carbohydrates and 24% from simple sugars.

8. Estimated Daily Calorie Needs, by Age Table 8.1

9. Trends in Caloric Intake Figure 8.1a

10. Trends in Caloric Intake (continued) Figure 8.1b

11. The Digestive Process • Digestive process – the process by which foods are broken down and either nutrients are absorbed or unused portions excreted by the body • Saliva – aids in chewing and swallowing, contains enzymes that begin CHO breakdown • Stomach – digestive organ that mixes food with enzymes and acids, protein breakdown begins • Small intestine – digests and absorbs nutrients • Liver major organ that determines whether nutrients are stored, sent to cells or organs, or excreted • Large intestine reabsorbs salts and water and sends remaining waste along tract

12. The Digestive Process Figure 8.2

13. Obtaining Essential Nutrients • Water • Can survive longer w/o food than water • Dehydration can occur in a few hours • Body is 50-60% water • Aids in fluid and electrolyte balance • Transports molecules and cells throughout body • Major component of blood • Carries oxygen and nutrients to tissues • Removes metabolic waste

14. Proteins • Proteins are major component of every cell • Are made up of amino acids and have 4 calories/gram • There are 9 essential amino acids the body doesn’t make and must be obtained from diet • The other 11 are produced naturally by the body • Complete protein foods contain the 9 essential amino acids. Typically animal products contain complete protein • Food from plant sources are typically incomplete; however is it possible to use a combination of plant sources to obtain all 9 essential amino acids • Americans rarely suffer from protein deficiency

15. Complementary Proteins Figure 8.3

16. Calculating Your Protein RDA Figure 8.4

17. Carbohydrates (CHO) • Supply us with energy to sustain daily activity • Carry 4 calories/gram, quicker, effecient metabolism • 2 major types of CHO • Simple Sugars • glucose, fructose (monosaccharides) • sucrose, lactose, galactose (disaccharides) • Complex CHO (polysaccharides) are found in grains, cereals, certain vegetables, beans and potatoes

18. Carbohydrates and Fiber • Complex Sugars: 2 major forms • starches: breads, pastas, rice, potatoes store as glycogen • Fiber or cellulose • Fiber – the indigestible portion of plant foods that helps move foods through the digestive system - plays an important role in good nutrition • Most Americans do not get the recommended daily amount of 20-35 grams

19. Fiber • Insoluble fiber – associated w/ GI benefits and lower risk for some cancers. Found in bran, whole-grain breads and cereal, and most fruits and vegetables. • Soluble fiber – factor in reducing cardiovascular heart disease by lowering blood cholesterol levels. Found in oat bran, dried beans, and some fruits and vegetables

20. Fiber Benefits • Protection against colon and rectal cancer • Protection against breast cancer • Protection against constipation • Protection against diverticulosis • Protection against heart disease • Protection against diabetes • Protection against obesity

21. Increasing Fiber • Aim for 20-35 grams/day • Select whole-grain breads (not just whole wheat) • Choose bread w/ 3 or more grams fiber/serving • Eat fruit and vegetable skins • Choose fruit over fruit juices • Sprinkle ground flaxseed on cereals and baked goods • Use whole-grain pastas, crackers, cookies, etc • Limit consumption of highly refined white flour products

22. Fats • Fats (lipids) – vital role in maintaining health skin and hair, insulating body organs against shock, maintaining body temperature, and promoting health cell function • They contain 9 calories/gram • They make foods taste better • Carry fat soluble vitamins A,D,E,K • Provide concentrated form of energy in the absence of CHO

23. FATS • Triglycerides – most common form of fat circulating in the blood (95 percent of body fat). The liver converts excess calories into triglycerides • Cholesterol – the remaining 5 percent of body fat, can accumulate on the inner walls of arteries. Is a component of all cell membranes and is a necessary part of our diet. • Plaque – the build up of cholesterol; major cause of atherosclerosis • HDL: high density lipoproteins, transport circulating cholesterol to the liver. High HDL “good cholesterol” levels are desirable; increased w/ regular aerobic exer. • LDL: low density lipoproteins, play a role in clogging arteries. Lower LDL levels are desirable to reduce the risk of heart disease. “Bad cholesterol”

24. FATS • Fat cells consist of chains of carbon and hydrogen • Saturated fats are unable to hold any more hydrogen • They generally come from animal sources like meats and diary products • They are solid at room temperature • Unsaturated fats have room for additional hydrogen atoms in their chemical structure • They come from plant and vegetable oils • They are generally liquid at room temperature

25. PUFAs and MUFAs • MUFAs, monounsaturated fatty acids and PUFAs, polyunsaturated fatty acids, refer to the number of hydrogen atoms that are missing from their chemical structure. • MUFA: preferred fats due to possible lowering of LDL levels. Examples include olive and peanut oils • PUFA: less desirable than MUFA, associated with lowering levels of HDL. Examples include corn, safflower and sunflower.

26. Trans-fatty Acids • Trans-fatty acids – fatty acids that are produced when polyunsaturated oils are hydrogenated to make them more solid and extend shelf life. • They are known to: • Raises LDL and lower HDL • Increase risk of heart disease • Increase risk of certain types of cancer • New FDA rules require labels to tell consumers how much trans fat is the food but only for amounts greater than 500mg. If a product claims to be trans-fat free it just has less than 500mg…

27. Percentages of Saturated, Polyunsaturated and Monounsaturated Fats in Common Vegetable Oils Figure 8.5

28. Essential Fatty Acids • Linoleic acid and alpha-linolenic acids are 2 fats that are needed to make hormone like compounds that control immune function, pain perception and inflammation. • Linoleic acid: part of the omega-6 family of fats. Found in soybeans, peanuts, corn and sunflower seeds. Helps reduce LDL levels. • Alpha-linolenic acids: part of the omega-3 family of fats. Found in flax, canola, sardines, green leafy vegetables, walnuts, salmon and tuna. • Americans eat far more omega-6 fats

29. Choosing Good Fats In Your Diet • Read food labels • Pick MUFA/PUFA w/ least amount of calories • Use olive oil, peanut oil, canola oil • Eat fish high in Omega 3’s • Choose lean meats • Add walnuts and flaxseeds • Select low fat dairy products • Limit processed and convenience foods • Eat fatty fish twice weekly

30. Vitamins • Vitamins – essential, organic compounds that promote growth and help maintain life and health • Convert food energy to body energy • Age, heat can destroy vitamins in foods • Fat soluble – are absorbed through the intestinal tract with the help of fats (vitamins A, D, E, and K) • Tend to be stored in the body and toxic levels can accumulate in the liver • Water soluble – easily dissolved with water (B complex and vitamin C) • Are easily excreted and cause few toxicity problems

31. Minerals • Minerals are inorganic, indestructible elements that aid physiological processes w/in body • w/o minerals body can not absorb vitamins • Macrominerals: needed in fairly large amounts: sodium, calcium, phosphorous, magnesium, potassium, sulfur and chloride • Trace minerals: needed in small amounts: iron, zinc, manganese, copper and iodine • See Table 8.4 on pg 258 for a guide to minerals. Problems can occur with deficient and excessive levels.

32. A Closer Look at Sodium • Sodium: daily recommendation is for 1,100 – 2,300 mg/day • Average American consumes > 4000 mg/day • There is a controversial link btwn sodium intake and hypertension. • High sodium intake may increase calcium loss in urine increasing risk of osteoporosis • Majority of sodium in diet comes from processed foods and is used to enhance flavor and for preservation

33. A Closer Look at Calcium • Calcium: plays a role in building strong bones and teeth, muscle contraction, blood clotting, nerve impulse transmission, regulating heartbeat and fluid balance in cells. • Recommended intake is 1,200mg for most adults. • Vitamin D improves absorption of Ca. Sunlight helps manufacture Vitamin D. • Good sources of green leafy vegetables that contain Ca include broccoli, pinto beans and soybeans • Carbonated beverages contain phosphoric acid which increases Ca excretion (Ca is pulled out from bones)

34. A Closer Look at Iron • Iron is found in every living cell of all living things • Women 18-50 years old need about 18 mg/day • Men of same age range need about 10mg/day • Iron deficiency can produce anemia, which is the inability to produce hemoglobin • Iron deficient person feels tired and run down and women are at higher risk. Why? • Hemochromatosis is iron toxicity due to ingesting too many iron-containing supplements. Symptoms include vomiting, diarrhea, rapid heartbeat, weak pulse, shock and confusion. Can be fatal especially in children.

35. Determining Your Nutritional Needs • Recommended Dietary Allowances (RDAs): guidelines for the recommended average daily intakes of energy and nutrients considered adequate to meet the needs of most healthy people in the US • Dietary Reference Intake (DRI): newer version of the RDA. A set of nutritional values including more than 26 essential vitamins and minerals; applies to healthy people. • DRIs are considered the umbrella guidelines under which the following categories fall:

36. Dietary Reference Intakes • U.S. Recommended Allowances (USRDAs): reference standard for intake levels necessary to meet the nutritional needs of 97-98% of healthy individuals • Adequate Intake (AI): the recommended average daily intake level of a nutrient by healthy people when there is not enough research to determine the full RDA. • Tolerable Upper Intake Level (UL): the highest amount of a nutrient an individual can consume daily without the risk of adverse health effects.

37. Reading Labels for Health • Reference Daily Intakes (RDIs): recommended amounts of 19 vitamins and minerals (micronutrients) • Daily Reference Values (DRVs): recommended amounts for macronutrients like total fat, saturated fat, cholesterol, total carbohydrates, dietary fiber, sodium, potassium and protein. • Together the RDIs and DRVs make up the Daily Values (DVs) that you read on food and supplement labels listed as a percentage (% DV) • also includes info on serving size, calories, calories from fat/serving and percentage of trans fats.

38. Reading a Food Label Figure 8.6

39. The MyPyramid Plan Figure 8.7