Introduction to Human Nutrition

1. Introduction to Human Nutrition Course Web Page

2. Chapter Outline • Nutrition defined (1.1) • Nutrition and health (1.1, 1.6) • Healthy People 2020 goals (1.5) • Classifying the nutrients (1.2) • Nutritional research • Hunger and appetite (1.7) • Factors impacting food choices, small group exercise

3. Nutrition Defined • Nutrition – the science of foods and the nutrients they contain • Study the: • action of foods and the nutrients in the body • relationship between diet and health

4. Nutrition Defined • Actions in the body include: • Ingestion • Digestion • Absorption • Transport • Metabolism • Excretion

5. Nutritional Goals • Quality intake that allows you to function at your best and promotes health. • Intake that provides adequate levels of each nutrient • Quantity of intake that promotes a healthy body weight.

6. Diet and Health • Diet - the foods one consumes • The quality of your daily diet affects the risk of chronic diseases • Meaning…..The food choices you make daily have a cumulative impact on your health

7. Nutrition and Health • Chronic health issues associated with diet include: • Cardiovascular disease • Hypertension • Obesity • Type II Diabetes • Osteoporosis • See pages 5/6

8. Leading Causes Death - US • Heart disease: 616,067 • Cancer: 562,875 • Stroke: 135,952 • Chronic respiratory diseases: 127,924 • Accidents (unintentional injuries): 123,706 • Alzheimer's disease: 74,632 • Diabetes: 71,382 • Influenza and Pneumonia: 52,717 • Kidney disease: 46,448 • Septicemia: 34,828 CDC, 2009

9. Improving your Health • Goal is to reduce the number of risk factors that are in your control • Risk factor = something that statistically increases the incidence of a disease • Risk factors may not be the cause of the disease

10. Improving Health • Risk factors in your control: • Smoking • Alcohol intake • Over-consumption of calories • Physical inactivity • Poor quality diet

11. Improving Health • Risk factors you cannot control: • Age • Gender • Genetics (family history) • Ethnicity

12. Maine Data • 27% report NO physical activity • 1 in 5 engage in moderate physical activity ~5 days/week • 74% do NOT eat 5 servings of fruits and vegetables daily • 25% of Maine adults are obese (2007)

13. Healthy People 2020 • Americans with a healthful diet: • Consume a variety of nutrient-dense foods within and across the food groups, especially: • whole grains, fruits, vegetables, low-fat or fat-free milk or milk products, and lean meats and other protein sources. • Limit the intake of saturated and trans fats, cholesterol, added sugars, sodium (salt), and alcohol.

14. Healthy People 2020 • Limit caloric intake to meet caloric needs. • All Americans should avoid unhealthy weight gain, and those whose weight is too high may also need to lose weight

15. What’s Considered Food? • Foods contain nutrients and are derived from plant or animal sources • Nutrients are used by the body to provide energy and to support growth, maintenance and repair of body tissues • ~ 40 nutrients identified at this time

16. Classifying Nutrients There are 6 Classes of Nutrients 1. Carbohydrates 2. Lipids (fats) 3. Proteins 4. Vitamins 5. Minerals 6. Water

17. Body Composition

18. Describing the Nutrients • There are several ways to classify the classes of nutrients. • Essential or nonessential • Organic or inorganic • Macronutrient or micronutrient • Energy yielding or not

19. Classifying Nutrients • Essential nutrients– nutrients the body either cannot make or cannot make enough of to meet its needs. • These nutrients must be obtained from foods (ingested in some manner) • Examples: • Vitamins • Calcium, iron, and other minerals • Some of the amino acids

20. Essential Nutrients • To be classified as an essential nutrient: • The biological function of nutrient is known • Omission from the diet leads to a decline in a biological function • Return of the nutrient restores the biological function

21. Classifying Nutrients • Nonessential nutrients– body can make from other nutrients ingested  Examples: • Cholesterol • Some amino acids

22. Classifying Nutrients by Composition • Organic nutrients - contain carbon • Carbohydrates • Lipids • Proteins • Vitamins • Inorganic nutrients - do not contain carbon • Minerals • Water

23. Quantity Needed • Macronutrients: need in relatively large amounts • Carbohydrates, lipids, proteins • Micronutrients: need in relatively small amounts • All other nutrients

24. Classifying Nutrients • Energy-yielding nutrients (3): • Carbohydrates • Fats (lipids) • Proteins • Where does the energy come from?

25. A little more on energy • Measure energy in kilocalories in U.S. • What most think of as a “calorie” is really a kilocalorie • Kcal = amount of energy needed to raise the temperature of 1 kg of water by 10C • Measure energy in kilojoules (kJ) in most other countries

26. Energy in the Body • The body uses the energy yielding nutrients to fuel all activities • All energy yielding nutrients are “caloric”. • If more energy is ingested than is needed to fuel body activities the extra energy is stored as _________ and ________ occurs.

27. Energy-Yielding Nutrients

28. Energy-Yielding Nutrients • Carbohydrates: C, H, O • 4 kcal/gram • Body’s primary source of energy • Use as glucose • Glucose is the brain’s only source of energy • Carbohydrate stores are limited ~12-24 hours (in liver and muscle)

29. Classes of Carbohydrates • Simple sugars • Monosaccharides and disaccharides • Complex carbohydrates • Starch • Fibers • Carbohydrate rich foods……..

30. Lipids • Lipids – fats and oils: C, H, O • 9 kcal/gram • Body’s alternate source of energy • Use fat along with glucose as an energy source most of the time • Stores are unlimited

31. Types of Lipids • Fats – solids • Oils – liquids • Saturated (solids/fats) • No carbon to carbon double bonds • Unsaturated (liquids/oils) • Carbon to carbon double bond(s) present • Lipid rich foods?

32. Proteins • Proteins: C, H, O, N, S • 4 kcal/gram (same as _______) • Body’s least desirable source of energy • WHY? ……. • Protein is used for energy only when carbohydrate is NOT available as an energy source. • Protein rich foods?

33. Energy-Yielding Non-nutrient • Alcohol – 7 kcal/gram • Non-nutrient because it interferes with growth, maintenance and repair of the body • Alcohol’s metabolites are harmful

34. Energy Density • Measure of the kcal per gram of food • _______ has the highest energy density of the 3 energy-yielding nutrients. • Foods with a high energy density provide more kcal per gram than low density foods.

35. Energy Density

36. Evaluating a Food Label • _____ grams carbohydrate • _____ grams fat • _____ grams protein • TOTAL KCAL: ____________

37. 6 Classes of Nutrients • Carbohydrates • Lipids (fats and oils) • Proteins • Vitamins • Minerals • Water Pages 8/9

38. Vitamins • Essential • Organic, micronutrient • Not energy-yielding • Can be water-soluble or fat-soluble Examples:

39. Minerals • Essential • Inorganic, micronutrient • Major minerals: Ca, P, Na • Trace minerals: Fe, Zn • Not energy-yielding • Indestructible

40. Water • Water (H2O) • Essential • Organic or inorganic? • Noncaloric • We are ~60% water

41. Not everyone has access to clean water

42. Food Choices • Small group exercise • What influences your food choices each day? • Why do you eat what you eat? • Get into groups of ~4 and make a list of what impacts your food choices most days. • Turn this list in next time we meet.

47. Personal preferences Habit Ethnic heritage Tradition Social interactions or pressure Availability Convenience Economy $ Positive or negative associations Emotional Comfort Values -Religious, political, environmental Health concerns Nutritional value Food Choices