Nutrition Research Overview

1. Nutrition Research Overview • From Research Study to Media • Primary & Secondary Sources • Scientific Method • 7 steps • 2 main types of research designs • Observational • Experimental • One Study Doesn’t Prove a Finding

2. Primary vs Secondary Sources • Secondary Sources: • Resource that informs us of scientific research • Science writing in newspaper, magazine, TV news, internet, etc. • Primary Sources: • Original Research • Best research is published in peer-reviewed journals • As scientific information gets interpreted by others, less detail is provided and more opinion and sensationalism is introduced

3. Headline: Lack of Vitamin D Makes Kids Fat • Research at U of M (published in JCN)followed 479 youngsters over 30 months. • “We found that the kids with the lowest Vitamin D levels…tended to gain weight faster than the kids with higher levels.” • “Our findings suggest that low vitamin D status may put children at risk of obesity.” www.naturalnews.com

4. Scientific Method • Process of gaining scientific knowledge through the observation of measurable evidence. • Steps used by scientists to explain observations.

5. Scientific Steps: • Question or observation • Hypothesis (testable statement) or Purpose of study • Design: • Develop a plan to test the hypothesis • 2 main types: observational & experimental • Implement the research design • Collect & analyze data • Interpret results • State results or accept/reject hypothesis

6. Scientific Step: Design • Base design on whether study is determining correlation or cause & effect • Correlation (Association): When a change in one variable is RELATED to a change in another variable. • Cause and Effect: When a change in one variable CAUSES a change in another variable • 2 Main Types of Research Design • Observational • Epidemiological, Retrospective, Prospective • Experimental • Intervention, Clinical Trial

7. Observational Study • Scientists do NOT ask people to change their behaviors or undergo any treatment. • Data collected by recording observations & data • Minimal risk to participants • Suggests correlation (association), NOT cause & effect • Risk factors: conditions that increase the likelihood that a particular disease or condition will develop. • A type of Observational Study • Prospective study

8. Prospective Study • Pro-spective – looking ahead • “What will happen to me”? • Also called “cohort” study (study a group) • Follow a group of healthy people with different levels of exposure and observe effects on health or disease. • Disadvantages: expensive, time-consuming, may lose subjects • Advantages: ethical • Framingham Study • Began in 1948 to determine relationship between diet, lifestyle and heart disease.

9. Prospective study

10. Experimental Study • Researchers intervene -some exposed to “treatment”, others in control group (no treatment) • Random assignment • The participants have an equal chance to be in experimental or control groups • Factors that may affect the outcome are distributed equally among groups • Single-blind: • Participants in control group are given a placebo • The participants do not know who receives treatment but researchers do know • Opportunity for bias: researcher may treat participants differently

11. Experimental Study, cont. • Double Blind • Neither the researcher nor participants knows whether treatment or placebo is given • A member of research team holds code for group assignments and does not participate in data collection • Laboratory (animal) and Clinical Trial (people) • “Gold Standard” clinical trial, particpants are randomly assigned and given treatment in a double blind method • Suggests cause & effect - if differences found between groups at end of study - treatment caused the effect

12. Observational vs Experimental

13. Scientific Steps: • Question or Observation • Purpose or Hypothesis (testable statement) • Design: • Develop a plan to test the hypothesis • 2 main types: observational & experimental • Implement the research design • Collect & analyze data • Interpret results • State results or accept/reject hypothesis

14. Scientific Steps: Implement, Analyze, Interpretation • Data collected on each participant • Analyze data to see if the difference between “Group A and Group B” is “statistically significant” • Statistical significance • The difference between groups did not happen by chance.

15. Scientific Step: State results or accept/reject hypothesis • If there is a “significant difference”, then results show a correlation or cause and effect • Findings reviewed by board of scientists. If conclusions are accurate, study results are published in a peer-reviewed scientific journal. • One study doesn’t prove a finding. Findings need to be repeated in several kinds of experiments, by different researchers. • News media may report new findings before confirmed by other research.

16. Analyzing Scientific Claims • Red flags for misleading advertising: • How were participants recruited? Were they randomly assigned? • Who paid for the study? Who conducted the research? Will the researcher financially benefit from a particular outcome? • Was the treatment given in a single or double blind method? • Were the results published in a peer-reviewed journal? Were the results statistically significant? • Are the recommendations based on a single study? • Is the study performed to sell a product? • Read the info after the asterisk (*). What are your thoughts?