1. What You Eat and Why PowerPoint Presentation adapted from Dana Wu Wassmer, MS, RD

2. What is nutrition?

3. N utrition is “the science of food, the nutrients and the substances therein, their action, interaction, and balance in relation to health and disease, and the process by which the organism ingests, absorbs, transport, utilizes, and excretes food substances”---- The Council on Food and Nutrition of the American Medical Association

4. Nutrition is the study of Nutrients in food Nutrients in the body

5. Science of Nutrition includes Anatomy Physiology Biochemistry Medicine Exercise

6. Nutrient Chemical substances in foods that contribute to health, many of which are essential parts of the diet Essential nutrients: substances that, when left out of the diet, lead to poor health Body can’t make them Body can’t make enough

7. Body Uses Nutrients for Energy Growth Maintenance Repair Regulating body processes

8. Nutrition is a Young Science First vitamins were isolated in the 1930s Most recent vitamin (B12) in 1948 Information is constantly changing and growing based on scientific evidence

9. Focus of Nutrition is Changing In the past, the emphasis was on preventing deficiencies

10. Current Focus Diet related to disease Using nutrients to prevent diseases Heart disease High blood pressure Some cancers Obesity Diabetes

11. Current Focus Using nutrients to prevent Problems of aging Osteoporosis Macular degeneration (disease of the eyes) Birth defects Spina bifida Cretinism

12. Why is nutrition important?

13. Nutrition and Health Poor diet and sedentary lifestyle are risk factors for chronic diseases: Disease of the heart (31% of all deaths) Cancer (23%) Cerebrovascular disease (~7%) Diabetes (3%) Account for ~2/3 of all death

14. Prevention Adequate nutrition Excess nutrition and obesity “Affliction of affluence” Inactivity Many diseases are preventable Your choice

15. Classes of Nutrients Essential nutrients Nonessential nutrients Energy-yielding nutrients Nutrients for growth, development, and maintenance Nutrients that regulate body processes

16. The Six Classes of Nutrients Carbohydrates Fats Proteins Vitamins Minerals Water The first 3 categories provide Calories

17. Carbohydrates Sugars Starches Fibers

18. Carbohydrates Composed of C, H, O Provide a major source of fuel for the body Basic unit is monosaccharide (glucose) Simple and Complex CHO Energy yielding (4 kcal /gm)

19. Carbohydrate Structure

20. Lipids Composed of C, H and fewer Os Basic unit is fatty acid Triglyceride is the major form of lipid Fats and oils

21. Lipid Structure

22. Role of Lipids Unsaturated Fatty Acids Saturated Fatty Acids Essential Fatty Acids Energy yielding (9 kcal /gm)

23. Proteins Composed of C, O, H, N Basic unit is amino acid Make up bones, muscles, other tissues, and components (9) Essential amino acids (11) Nonessential amino acids Energy yielding (4 kcal /gm)

24. Protein Structure

26. Vitamins Composed of various elements Organic (contain carbon atoms bound to hydrogen atoms) Fat soluble Water soluble Yield no energy

27. Role of Vitamins Vital to life Regulate body processes Needed in tiny amounts (micrograms and milligrams)

28. Minerals Inorganic substances (no carbon bound to hydrogen) Needed in tiny amounts Not destroyed in cooking Trace minerals (need <100 mg) Major minerals (need >100 mg) Yields no energy

29. Role of Minerals Structure Calcium: bones and teeth Blood Iron, copper Fluid Balance Sodium, potassium, chloride

30. Water Composed of H, O Vital to life Require about 8 cups/day Is a solvent, lubricant, medium for transport, chemical processes, and temperature regulator Makes up majority of our body Yields no energy

31. Phytochemicals Not nutrients, meaning they aren’t required for life Reduce disease risk Cancer Heart attack Age related blindness Come only from plants

32. Phytochemicals Food Sources

33. Composition NutrientsFrench FriesAdult Male CHO37%<1% Protein4%16% Fat17%16% Minerals1%6% Water41%62%

34. Transformation of Energy 1,000 calories = 1 kcal = 1(food) Calorie CHO PROTEIN FAT ALCOHOL ENERGY SOURCES

35. What is a Calorie? A measurement of energy “the amount of heat it takes to raise the temperature of 1 gram of water by 1 degree Celsius”

36. Energy Yielding Nutrients CHO: 4 kcal/gm Protein: 4 kcal/gm Fat: 9 kcal/gm (Alcohol: 7 kcal/gm) Adjusted for digestibility Account for substances (in food) not available for energy use

37. Contribution to Total Kcals One day’s intake (1980 kcal) 290 gm of CHO (x 4 kcal/gm) 60 gm of fat (x 9 kcal/gm) 70 gm of protein (x 4 kcal/gm) % of kcal as CHO= (290 x 4)/1980 = 0.59 or 59% % of kcal as Fat= (60 x 9)/1980 = 0.27 or 27% % of kcal as PRO= (70 x 4)/1980 = 0.14 or 14%

38. Desire to eat Hunger Physical biological drive Appetite Psychological drive

39. Satiety Regulated by the hypothalamus Feeding centers Meal size and composition Hormones

40. Influences of Food Choices

41. Goals of Good Nutrition Prevent malnutrition Deficiency diseases Osteoporosis/calcium Anemia/iron, B vitamins Scurvy/vitamin C

42. Goals of Good Nutrition Prevent overnutrition Excess intakes Calories Saturated Fat Cholesterol Sodium

43. Nutrition-Related Problems Obesity Increasing in all age groups Excess Calories Heart disease and strokes Calories Saturated fat Cholesterol Sodium

44. Nutrition-Related Problems Cancer Excess calories Excess Fat Too few fruits/vegetables Diabetes Excess calories

45. How are Nutrition Questions Answered? Questions asked Hypothesis generated Research experiments conducted Findings evaluated by investigators Findings evaluated by other scientists and published Follow-up experiments conducted to confirm or extend the findings

46. The Scientific Method at Work

47. Epidemiologial Studies The study of how disease rates vary among different populations For example: How does the rate of stomach cancer in Japan compare with that in Germany? Does not prove cause and effect, but can suggest a relationship Often a starting point for research

48. Animal Studies Animal studies are often a first step in testing a hypothesis Also, sometimes humans cannot be ethically used as subjects in research Must find a good “animal model”: a disease in animals that is similar to that in humans For example, Vitamin C is an essential nutrient in the guinea pig, but not in most other animals

49. Case Control Study Individuals who have the condition in question are compared with those who are similar in most respects, but don’t have the disease For example, middle aged men with lung cancer might be compared with middle aged men who don’t, in order to identify risk factors

50. Double-Blind Study Subjects are randomly divided into an experimental group, who receive a given treatment, and a control group, who do not Sometimes subjects serve as their own control Neither the subject nor the researcher knows which group the subject belongs to or when they are receiving the active treatment

52. Example of Hypothesis Testing in Blind Studies Epidemiological studies revealed that smokers who eat fruits and vegetables had a lower risk of lung cancer Hypothesis: beta carotene in the fruits and vegetables reduces the damage to the lungs caused by smoke

53. Hypothesis Testing in Blind Studies In a double blind study, smokers were given either beta-carotene supplements or placebo The risk of lung cancer was actually found to be higher in those treated with the beta carotene Association does not mean causation

54. Reporting Experimental Results Peer-reviewed journals American Journal of Clinical Nutrition Journal of the American Dietetic Association New England Journal of Medicine

55. Evaluating Nutrition Advice Who said it? Credentials Education Nutrition Experts Registered dietitian BS nutrition ADA approved courses Internship National ADA exam Ohio Licensed dietitian

56. Where Was it Published? Scientific journal Popular magazines Newspapers Disreputable source

57. Evidence Testimonial Anecdotal Poorly-designed experiment Single study Small group Short time frame Poorly controlled

58. Warning Signs Unaccepted principles No disadvantages Claims “cure” Too good to be true Bias against medical science “New” or “secret” Profit motive