Human Nutrition. How our diet determines Health & Wellness

Transcription

1 Human Nutrition How our diet determines Health & Wellness

2 Nutrition The study of food How it nourishes our body How it influences health A mix of Biological and Social Science Relatively new Pragmatic Focused on intervention, behavior modification & outcomes

3 Why should we care? Nutrition (and physical activity) contributes to wellness Wellness = the absence of disease Physical Emotional (including mental) Spiritual

4 Why should we care? Optimal nutrition prevents disease 1. Nutrient deficiency diseases Goiter, scurvy, pellagra, rickets 2. Diseases influenced by nutrition** Chronic diseases (heart disease, odesity, Type II diabetes) 3. Diseases in which nutrition plays some role Some cancers, Osteoporosis

5 Example: Obesity An emerging problem, just within last two decades

6 Table 1-5 Page 24

7 Table 1-6 Page 25

8 Optimal Nutrition Largely because of 2 and 3, acquiring optimal nutrition has become a national goal Goals of Healthy People 2010 (promoted by USDHHS) 1. Increase quality and years of healthy life 2. Eliminate health disparities

9 Another reason: Omnivore s Dilemma Knowing what to eat, how much to eat, and in what setting to do it is BASIC We ve been doing it pretty well for tens of thousands of years. Within the last 50 years or so, we ve forgotten how to do it. Due almost entirely to corporations that make money from selling us food products.

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11 What are Nutrients? Organic* (contain Carbon) & Inorganic molecules in food that are critical to human growth and function Carbohydrates * Lipids (Fats and oils) * Proteins * Vitamins * Minerals Water

12 Divisions of Nutrients Macronutrients provide energy to do work* Fats, carbs, proteins Required in large amounts Broken down and stored or rebuilt Micronutrients Required in much smaller quantities Vitamins and minerals Used primarily as-is

13 Energy of macronutrients Measured in kilocalories (kcal) = Energy required to raise the temp. of 1g of H 2 O by 1 C. Via bomb calorimetry On food labels, Calorie usually means kcal.

14 Energy Density of Two Breakfast Options Compared LOWER ENERGY DENSITY This 450-gram breakfast delivers 500 kcalories, for an energy density of 1.1 (500 kcal 450 g 1.1 = kcal/g). HIGHER ENERGY DENSITY This 144-gram breakfast also delivers 500 kcalories, for an energy density of 3.5 (500 kcal 144 g = 3.5 kcal/g).

15 Carbohydrates Primary source of Energy during activity (especially for our brain) C, H and O in ratio of 1:2:1 Provides 4 kcal/g

16 Fats (Lipids) Triglycerides, phospholipids Important E source during rest and low intensity activity Provide 9 kcal/g (far fewer Oxygens)

17 Proteins Contain C, H, O & Nitrogen (N)* Constructed of chains of Amino Acids (AA) Energy source only in dire need; 4 kcal/g

18 Important for: Proteins Bone structure (organic part of bones is protein) Regulating metabolism & fluid balance Repairing muscle & bone Build cells and tissues

19 Table 1-2 Page 9

20 Calculating Energy of foods 1 slice bread with 1 tbsp. peanut butter Carbs: 16g * 4 kcal/g = 64 kcal Protein: 7g * 4 kcal/g = 28 kcal Fat: 9g * 9 kcal/g = 81 kcal Total = 173 kcal

21 Vitamins Micronutrients (only need a little; e.g. mg, µg) Organic compounds that assist in regulating body processes and using E (do not supply E) 2 types based on solubility Fat-soluble Water-soluble

22 Fat-soluble vitamins Vitamins A, D, E, K Easily dissolve in fats and oils Easily stored in adipose tissue (fat cells) throughout the body Unnecessary to ingest or synthesize these every day

23 Water-soluble vitamins Vitamins C, B (thiamin, B 6, riboflavin, folate, etc.) Must ingest or synthesize these every day Your kidneys filter them from the blood & you excrete them in urine

24 Minerals Inorganic compounds (no Carbon) Remain intact (maintain same structure regardless of their environment) Major Sodium (Na + ) Chloride (Cl - ) Potassium (K + ) Calcium (Ca 2+ ) Phosphorous (P) Magnesium (Mg 2+ ) Minor Iron Zinc Iodine Selenium Copper Flouride Chromium Molybdenum

25 Minerals Essential to: Bone deposition (Ca, P, Mg) Delivering O 2 to cells and removing CO 2 (Fe) Initiating & sustaining muscle contraction (Na, K, Ca) Propagating nerve impulses (Na, K, Ca) Fluid balance & blood pressure (Na, K, Cl)

26 H 2 O ~ 2/3 of total body weight Dissolves organic and inorganic molecules making a solution (~55% of blood volume is water) Needed for chemical reactions Hydrolysis and dehydration synthesis High heat capacity Absorbs and retains heat without changing temp. or state = stability! Great medium for cooling the body Effective lubricant Reduces friction

27 Determining Nutrient Intake

28 Dietary Reference Intakes Updated nutritional standards Expand on traditional RDA Update existing standards Establish standards for nutrients without RDA values

29 Naive vs. Accurate View of Nutrient Intakes Danger of toxicity Safety Marginal Safety Tolerable Upper Intake Level RDA or AI RDA Danger Naive view Marginal Danger of deficiency Accurate view Estimated Average Requirement

30 Dietary Reference Intakes

31 Dietary Reference Intakes DRIs consist of 4 values: 1. Estimated Average Requirement (EAR) 2.Recommended Dietary Allowances (RDA) 3.Adequate Intake (AI) 4.Tolerable Upper-Intake Level (UL)

32 Dietary Reference Intakes Estimated Average Requirement (EAR) Average daily intake (ADI) level of a nutrient that meets the needs of 1/2 of the people in a particular category

33 Dietary Reference Intakes Recommended Dietary Allowance (RDA) The ADI level required to meet the needs of 97 98% of people in a particular category

34 Dietary Reference Intakes Adequate Intake (AI) Recommended ADI level for a nutrient Based on observations and estimates from experiments Used when the RDA is not yet established: calcium, vitamin D, vitamin K, fluoride

35 Dietary Reference Intakes Tolerable Upper Limit (UL) Highest ADI level that is not likely to have adverse effects on the health of most people Consumption of a nutrient at levels above the UL is not considered safe Anything consumed in excess is potentially dangerous

36 Dietary Reference Intakes Estimated Energy Requirement (EER) Average dietary energy intake (kcal) to maintain energy balance (neither gaining nor losing weight) Based on age, gender, weight, height, level of physical activity

37 Dietary Reference Intakes Acceptable Macronutrient Distribution Range (AMDR) Describes the portion of energy intake that should come from each macronutrient Nutrient Carbohydrate Fat Protein AMDR 45-65% 20-35% 10-35%

38 Your Goal Create a diet plan that is: nutritionally adequate allows you to maintain a healthy weight support your daily physical activities

39 The Scientific Method Reading scientific studies Observation Hypothesis Prediction Experiment Results Interpretations

40 Examples of Research Designs EPIDEMIOLOGICAL STUDIES CROSS-SECTIONAL COHORT Heart attack Examine a cultural or ethnic group of people at a single snapshot in time. Attempt to identify factors contributing to health Blood cholesterol Examine a group of people at multiple time steps. Watch for problems that develop & correlate eating patterns that contribute to disease.

41 EXPERIMENTAL STUDIES Examples of Research Designs LABORATORY-BASED LABORATORY-BASED HUMAN INTERVENTION ANIMAL STUDIES IN VITRO STUDIES (OR CLINICAL) TRIALS Feed one group of mice an experimental diet. Others get a control diet. Change eating habits of a group. See if disease symptoms improve.

42 A well- designed experiment Sample Size Blind Placebo Double-blind Researcher fallibility Correlation vs. Causation