Evaluating Nutrition Information

1. Evaluating Nutrition Information

2. 1. Sources of Nutrition Information • Government (Dietary Guidelines/ MyPlate) • Diet and health books • Internet websites • Food packaging • Family and Friends • Media (TV, newspapers, magazines) • Published findings of scientific studies • Classes • Nutritionists/dieticians

3. 2. Sorting Fact from Fallacies • People tend to believe what they hear repeatedly • To increase number of viewers (and make more money), media sensationalizes and over simplifies nutrition topics • Reports on studies’ findings often over state or distort information or lack important details • Be alert to the influences of your food choices • Recognize preconceived ideas about nutrition • Keep an open mind to current scientific evidence • Think critically

4. 3. The Science of Nutrition • Scientific studies are the cornerstone to reliable nutrition information • Antidotal evidence (reports of people’s individual experiences) can also be useful

5. 4. Scientific Process • Researchers test hypotheses (educated guesses) that arise from observations of a phenomena • Hypotheses are tested by researchers conducting a “study” (an experiment or doing research)

6. 5. Types of Nutrition Studies EPIDEMIOLOGICAL • Compares disease rates among population groups and attempts to identify related conditions/behaviors (ex. Diet and exercise) • Examples: - observation of scurry in sailors’ - observation of low rate of breast cancer in Japanese • Shows correlation (relationships between diet and disease) but not causation (the actual reason for the observation)

7. Types of Nutrition Studies ANIMAL STUDIES • Used as a starting point to help explain a hypotheses • Used because human studies are difficult to conduct and expensive • Must be followed-up with cell or human studies to verify findings because animals are differently physically and mental than humans

8. Types of Nutrition Studies CELL CULTURE STUDIES • Specific human body cells are isolated and grown in a laboratory • Study the effects of nutrients on cell processes • Nutrigenomics • The science of how genes, diet and disease interact to create health problems • Certain genes determine susceptibility to disease • Certain foods turn disease susceptibility genes on or off • Knowing family genetic tendencies helps determine best diet for the individual • Part of biochemical individuality

9. Types of Nutrition Studies HUMAN STUDIES • Case Control Studies • Small-scale epidemiological study • 2 closely-matching groups (age, gender, race) • One group has the health condition (ex. Diabetes) being examined, the other does not • Identify the factors (ex. Vegetable consumption) that differ between the groups • Provides clues about cause and prevention of disease

10. Types of Nutrition Studies HUMAN STUDIES • Clinical Trials • Researchers make a change (ex. Diet or exercise) and study the effects • Two subject groups: Experimental (people are given or make the change) and Control (similar people are not given or make the change) • Health and disease differences are measured between the two groups

11. Types of Nutrition Studies First Clinical Trial • Sailors on long ocean voyages in 1747 • Given oranges and lemons and did not develop scurvy (a condition of joint pain, skin sores and bleeding gums) • Something in the oranges/lemons prevented the disease • 40 years later – common practice to provide sailors with citrus fruit (limes, lemons, oranges) on long sea voyages to prevent scurvy – “Limeys” • 200 years later (1930’s) vitamin C is discovered as the “something” in citrus that prevented scurvy

12. 6. Reducing Errors (Bias) inHuman Studies • Groups as randomly assigned • Blind studies - Use of placebos (treatment or pill that only looks like the actual treatment of pill) • Double-blind study – Both the subjects and the researchers do not know who is or is not receiving the actual treatment/pill or a placebo • Expectation of treatment/pill effect (even when receiving the placebo) can alter study results. (Ex. Bulimia)

13. 7. Understanding Published Nutrition Information A) Why is nutrition information confusing and often contradictory? • Nutrition science is constantly changing with new findings from studies • Some studies are flawed (contain bias or errors)

14. Understanding Published Nutrition Information B) How is nutrition information disseminated (spread)? • Researchers publish their study findings in professional scientific journals • Before reliable study findings are published, they are peer-reviewed (judged/critiqued by other researchers) • Professional scientific journals are not commonly read by the general public

15. Understanding Published Nutrition Information C) What are the types (sources) of published nutrition information? • Primary – Professional scientific journals • Secondary – Scientific magazines/articles/books based on primary source • Science writing – General magazine, newspaper articles or books written by science writers • Mass media – Nightly news reports and internet websites/blogs Every time findings from the original research is summarized and restated, inaccuracies in interpretation of the information is possible

16. 8. Evaluating Internet Information • There are no rules for posting on the Internet • Consider the source • Who are the authors or sponsors of the site? • Is the information presented cited or documented? • Is the site up-to-date? • What are the qualifications of the author/sponsor? • .edu, .gov, and .org sites are more creditable than .com sites. • What is the motivation for the site? (education or selling products) • When studies are cited, consider their quality and purpose. Just because it is in print does not mean it is true.