Nutrition Research Overview

Transcription

1 Nutrition Research Overview From Research Study to the Media Secondary & Primary Sources Explore How Research is Conveyed in the News Scientific Method 7 Steps 2 Main Types of Research Design Observational Experimental One Study Doesn t Prove a Finding

2 Sources of Scientific Information Secondary Sources & Media: Resource that informs us of scientific research Scientific news from websites, blogs, TV, magazines, friends Primary Source: Original Research Best research is published in scientific (peer-reviewed) journals As scientific research gets interpreted by others, less detail is provided and more opinion and sensationalism is introduced

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4 Journalists who interpret scientific findings.some qualified and many not qualified Important to know if the information you receive is accurate.

5 News 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.

6 Scientific Method Process all scientists follow to gain scientific knowledge. There are 7 steps in the scientific method

7 Scientific Steps: 1. Question or observation 2. Purpose of study or hypothesis (a testable statement) 3. Design the study: ü Develop a plan to test the hypothesis ü Choose design type: observational or experimental 4. Implement the research design 5. Collect & analyze data 6. Interpret results 7. State results or accept/reject hypothesis

8 Scientific Step 3. Design Determine if finding 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 ü Prospective Experimental ü Clinical Trial

9 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 Can suggest association, NOT cause & effect

10 Prospective Study Prospective Study type of observational study Follow a group of healthy people with different levels of exposure and observe effects on health or disease. Risk factor: a condition or behavior that increase the likelihood that a particular disease or condition will develop. Framingham Study Began in 1948 to determine relationship between diet, lifestyle and heart disease.

11 Prospective study

12 Experimental Study Researchers intervene Participants divided into treatment or control (no treatment) group Can suggest cause & effect Random assignment Participants have equal chance to be in treatment or control group Factors that may affect the outcome are distributed equally among the two 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

13 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 If significant difference found between treatment & control group treatment caused the effect

14 Headline: Lack of Vitamin D Makes Kids Fat Research at U of M (published in Journal of Clinical Nutrition) 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.

15 Ice Cream & Drowning Studies have shown people are more likely to drown in places where ice cream sales are high. The higher the ice cream sales the more likely people are going to drown.

16 u If you eat ice cream, are you more likely to drown? u What is the connection (association) between ice cream & drowning?

17 Water associated with drowning, not ice cream Ice cream sales tend to be high near water (pools and beaches) people more likely to drown near water. The connection (association) is between water and drowning.

18 Headline: Ice Cream Makes People Drown How accurate is this headline? Not accurate Somewhat inaccurate Neutral Somewhat accurate Accurate Why?

19 Studies that find correlations Ice Cream & Drowning Studies have shown there is a correlation (association) between high ice cream sales and drowning. It is NOT the high ice cream sales but water that is associated with drowning. Vitamin D & Weight Research found there is a correlation (association) between kids with low Vitamin D and weight gain. Vitamin D may OR may not be associated with weight gain (more studies needed)

20 Scientific Steps: 1. Question or Observation 2. Purpose or Hypothesis (testable statement) 3. Design: ü Develop a plan to test the hypothesis ü 2 main types: observational & experimental 4. Implement the research design 5. Collect & analyze data 6. Interpret results 7. State results or accept/reject hypothesis

21 Scientific Steps: 4. Implement, 5. Analyze, 6. Interpretation 4. Implement: Data collected on each participant 5. Analyze data to see if the difference between Group A & Group B is statistically significant Statistical Significance: The difference between groups did not happen by chance. 6. Interpret: What new knowledge was gained by this research?

22 Scientific Step 7. State results & accept/reject hypothesis If there is a statistically significant difference, then results show a correlation or cause & 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 studies, by different researchers. News media may report new findings before confirmed by other research.

23 Observational vs Experimental Type of study Ethical? Results Random Assign? Dbl Blind? Observational Experimental

24 Semi-Starvation Study 1. Observation: People are starving in Europe during WWII 2. The Purpose: Gain insight into the physical & psychological effects of starvation Determine how to rehabilitate people who are starving from the food shortage during WWII in Europe. 3. Design the study: You are on Ancel Keye s research team It is 1943 and there is no ethics committee The study can last no longer than 1 year. What kind of study design would you use; Observational or Experimental? WHY? Where would you find participants? BRAINSTORM