The Role of Nutrition in Our Health

1. 1 The Role of Nutrition in Our Health

2. What Is Nutrition? • Food refers to plants and animals we eat • Nutrition is the science that studies food: • How food nourishes our bodies • How food influences our health

3. Why Is Nutrition Important? • Proper nutrition supports wellness • Wellness is more than the absence of disease • Physical, emotional, and spiritual health • Active process • Critical components of wellness • Nutrition • Physical activity

4. Why Is Nutrition Important? • Healthful diet can prevent disease • Poor nutrition causes deficiency diseases: scurvy, pellagra • Nutrition plays a role in osteoporosis and cancer • Nutrition is associated with chronic diseases: heart disease, stroke, and diabetes

5. Why Is Nutrition Important? Obesity is a growing problem: • Eating more calories than expended • Risk factor for heart disease, stroke, type 2 diabetes, and some forms of cancer

6. Why Is Nutrition Important? • Nutrition is a national goal to promote optimal health and disease prevention • Goals of Healthy People 2020 • Increase quality and years of healthy life • Eliminate health disparities

8. What Are Nutrients? • Nutrients are chemicals in foods that our bodies use for growth and function • Organic nutrients contain carbon, an essential component of all living organisms • Carbohydrates, lipids, proteins, vitamins • Inorganic nutrients: nutrients that do not contain carbon • Minerals and water

9. Determining Nutrient Needs • Dietary Reference Intakes (DRIs): updated nutritional standards • Expanded on the traditional RDA values • Set standards for nutrients that do not have RDA values • Dietary standards for healthy people only • Aim to prevent deficiency diseases and reduce chronic diseases

10. Determining Nutrient Needs Dietary Reference Intakes (DRIs) consist of: • Estimated Average Requirement (EAR) • Recommended Dietary Allowance (RDA) • Adequate Intake (AI) • Tolerable Upper Intake Level (UL) Dietary Reference Intakes (DRIs) Determination

11. Determining Nutrient Needs • Estimated Average Requirement (EAR) • The average daily intake level of a nutrient to meet the needs of half of the healthy people in a particular life stage or gender group • Used to define the Recommended Dietary Allowance (RDA) of a nutrient

12. Determining Nutrient Needs • Recommended Dietary Allowance (RDA) • The average daily nutrient intake level that meets the needs of 97% to 98% of healthy people in a particular category

13. Determining Nutrient Needs • Adequate Intake (AI) • Recommended average daily nutrient intake level • Based on observed and experimentally determined estimates of nutrient intake by a group of healthypeople • Used when the RDA is not available: calcium, vitamin D, vitamin K, and fluoride

14. Determining Nutrient Needs • Tolerable Upper Intake Level (UL) • Highest average daily nutrient intake level likely to pose no risk of adverse health effects to most people • Consumption of a nutrient at levels above the UL increases the potential for toxic effects and health risks increases

15. Determining Nutrient Needs • Estimated Energy Requirement (EER) • Average dietary energy intake to maintain energy balance in a healthyadult • Defined by age, gender, weight, height, and level of physical activity

16. Determining Nutrient Needs • Acceptable Macronutrient Distribution Ranges (AMDR) • Ranges of energy intakes from macronutrients that are associated with reduced risk of chronic disease while providing adequate intakes of essential nutrients • If nutrient intake falls outside this range, there is a potential for increasing our risk for poor health

18. Assessing Nutritional Status • Nutrition professional must have a thorough understanding of the client’s current nutritional status • Weight • Ratio of lean body tissue to body fat • Intake of energy and nutrients • Foundation of recommended dietary and lifestyle changes • Baseline for evaluation

19. Malnutrition • Nutritional status is out of balance:too much or too little of a particular nutrient or energy over a significant period of time • Undernutrition: too little energy or too few nutrients over time, causing weight loss or a nutrient-deficiency disease • Overnutrition: too much energy or too much of a given nutrient over time, causing obesity, heart disease, or nutrient toxicity

20. Physical Examinations • Physical exams are conducted by trained healthcare providers • Tests depend upon client’s medical history, disease symptoms, and risk factors • Typical tests include vital signs, lab tests, heart and lung sounds • Nutritional imbalances may be detected by examining hair, skin, tongue, eyes, and fingernails

21. Health History Questionnaire • Tool to assist in cataloging history of health, illness, drug use, exercise, and diet • Socioeconomic factors (education, access to shopping/cooking facilities, marital status, ethnic/racial background) • Energy and nutrient intake questionnaires

22. Dietary Intake Tools • Techniques to assess nutrient and energy intakes: • Diet history • Twenty-four-hour dietary recall • Food frequency questionnaire • Diet records • Strengths and limitations

23. Diet History • Information from interview or questionnaire: • Weight (current and usual weight, goals) • Factors affecting appetite and food intake • Typical eating pattern • Disordered eating behaviors (if any) • Education and economic status • Living, cooking/food purchasing arrangements • Medication and dietary supplements • Physical activity

24. Twenty-Four-Hour Dietary Recalls • Recalls all food and beverages consumed in the previous 24-hour period • Accurate recall includes serving sizes, food preparation methods, and brand names of convenience foods or fast foods • Limitations: • May not be typical intake • Relies on memory • Relies on ability to estimate portion sizes

25. Food Frequency Questionnaires • Determine typical dietary pattern over a predefined period of time • Include lists of foods with the number of times these foods are eaten • Some assess only qualitative information (typical foods without amounts) • Semiquantitative questionnaires assess specific foods and quantity consumed

26. Diet Records • List of all foods and beverages consumed over a specific time period (3−7 days) • Improved accuracy when: • Foods are weighed or measured • Labels of convenience foods and supplements are saved • Challenges to accuracy and sufficient detail

27. Anthropometric Assessment • Common measurements include height, body weight, head circumference in infants, and limb circumference • Require trained personnel and correct tools • Compare standards specific for age/gender • Assess trends in nutritional status/growth

28. Nutrition Deficiencies • Primary deficiencyoccurs when a person does not consume enough of a nutrient, a direct consequence of inadequate intake • Secondary deficiencyoccurs when: • A person cannot absorb enough of a nutrient in his or her body • Too much of a nutrient is excreted from the body • A nutrient is not utilized efficiently by the body

29. Deficiency Symptoms • Subclinical deficiency occurs in the early stages; few or no symptoms are observed • Covert symptoms are hidden and require laboratory tests or other invasive procedures to detect • Symptoms of nutrition deficiency that become obvious are overt

30. Scientific Method To ensure that certain standards and processes are used in evaluating claims, the researcher: • Makes an observation and describes a phenomenon • Proposes a hypothesis (educated guess) to explain the phenomenon • Develops an experimental design to test the hypothesis 4. Collects and analyzes data to support or reject the hypothesis

31. Scientific Method • If the data are rejected, an alternative hypothesis is proposed and tested • If the data support the original hypothesis, a conclusion is drawn • The experiment must be repeatable, so other researchers can obtain similar results

32. Well-Designed Experiment • The sample size (number of people being studied) should be adequate enough to ensure that the results obtained are not due to chance alone • A control group is essential to comparison between treated and untreated individuals • Control for other variables to avoid coincidentally influencing the results

33. Advancing a Theory • A hypothesis that is supported by repeated experiments may be called a theory • A theory represents a scientific consensus (agreement) of why the phenomenon occurs • Theories can be challenged and changed as scientific knowledge evolves

34. Epidemiological Studies • Also known as observational studies: • Involve assessing nutritional habits, disease trends, or other health phenomena of large populations • Determine the factors that may influence these phenomena

35. Model Systems • Human studies: • Difficult to control for all of the variables • Humans have long life spans • Animal studies • Preliminary information for designing and implementing human studies • Research that cannot be done with humans • Drawbacks: results may not apply directly to humans; ethical implications of animal studies

36. Human Studies • Case control studies are epidemiological studies done on a smaller scale • Compare a group of individuals with a particular condition to a similar group without this condition • Clinical trials are controlled experiments • Experimental group receives the intervention • Control group is not given the intervention

37. Double-Blind, Placebo-Controlled Study • Most likely to produce valid, reliable data • Blinding • Neither researchers nor participants know which group is really getting the treatment • Helps prevent the researchers from seeing only the results they want to see • Placebo: imitation treatment that has no scientifically recognized therapeutic value • Psychosomatic effect orplacebo effect

38. Evaluating Media Reports • Discerning truth or fallacy: • Who is reporting the information? • Who conducted the research; who paid for it? • Is the report based on reputable research studies? • Is the report based on testimonials? • Are the claims too good to be true? • Quackery: misrepresentation of a product, program, or service for financial gain

39. Trustworthy Nutrition Experts • Registered dietician (RD) • Licensed dietician meets the credentialing requirements of a given state • Nutritionist has no legal definition • Professional with advanced nutrition degree (master’s—MS, MA; doctoral—PhD) • Physician

40. Government Information Sources • Centers for Disease Control and Prevention (CDC) • National Health and Nutrition Examination Survey (NHANES) • Behavioral Risk Factor Surveillance System (BRFSS) • National Institutes of Health (NIH)

41. Reliable Nutrition Information • American Dietetic Association • American Society for Nutrition Sciences • Society for Nutrition Education • American College of Sports Medicine • North American Association for the Study of Obesity