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
Primary vs Secondary Sources
! Secondary Sources:
! Learn about scientific findings via websites, 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
Scientific Method
! Process all scientists follow to gain
scientific knowledge.
! There are 7 steps in the scientific
method
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. 
5. 
6. 
7. 
Implement the research design
Collect & analyze data
Interpret results
State results or accept/reject hypothesis
Scientific Step 3. Design
! Choose design to show 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
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
Prospective Study
! Prospective Study – one 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 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.
Prospective study
Ice Cream Causes Drowning?
! Statistical studies have shown that drowning
rates are highest in areas with strong ice
cream sales.
! Does ice cream cause drowning?
! What is the association (link) between ice
cream sales & drowning?
Experimental Study
! Researchers intervene
! Can suggest cause & effect
! Participants divided into treatment or control (no treatment) group
! 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
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
Observational vs Experimental
Type of study Ethical?
Observational
Experimental
Results Random Dbl
Assign? Blind?
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.”
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. 
5. 
6. 
7. 
Implement the research design
Collect & analyze data
Interpret results
State results or accept/reject hypothesis
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 and Group B” is “statistically
significant”
6.  Interpret: Looking for statistical significance
! The difference between groups did not happen by
chance.
Scientific Step 7. State results
or 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.
1943 - 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