1. Can descriptive and correlational studies give us information about causation, that is,
whether one factor is the cause of another? Why or why not?
a. No
i. They may be related, but that doesn’t mean they are causing it. There
may be a third factor we don’t know about
2. What type of studies would we have to perform to collect evidence that one factor is the
cause of a specific outcome?
a. Experimental Studies
● Why are systematic reviews necessary for determining cause-effect relationships better?
○
● Why are meta-analyses statistically stronger than the analysis of any individual study?
○due to increased numbers of subjects, greater diversity among subjects, or
accumulated effects and results.
❏What observations formed the basis of the initial idea that high fat consumption cause
heart disease?
❏In Naples, Ancel Keys watched working class people and their diets. He saw that
working class they ate less meat and more pasta. They weren’t eating as much
fat as upper class. He saw the connection of cholesterol
❏Why did scientists around mid 1950s think that eating a particular kind of fat, saturated
fat, caused cholesterol buildup in the arteries which lead to heart attacks?
❏He saw cholesterol and fat were connected
❏Saw blood cholesterol went up with consumption of eating red meat and
dairy products
❏Was there enough scientific evidence for the initial recommendation for eating less fat to
reduce heart disease?
❏Keys saw a correlation between increase of meat consumption and high heart
disease amounts
❏There were associations but no causations so not enough scientific evidence
❏What are the consequences of consuming foods that are low-fat or fat-free but have high
amounts of refined carbohydrates?
❏More calories were eaten
❏ Were the conclusions drawn for high fat or saturated fat intake causing heart disease
based on correlational or experimental studies? Can we obtain cause and effect
relationships simply from correlations or associations?
❏ No we can’t have cause and effect from correlation
❏They were based on correlational studies
● What is a fat molecule (triglyceride) made of?
○ Glycerol, fatty acids chains
● What part of the fat molecule determines whether the fat is solid or liquid at room
temperature?
○ Fatty acids
● What is the chemical difference between a saturated and an unsaturated fatty acid?
○ Saturated has only a single carbon bond, unsaturated has a double carbon bond
● What is a trans-fat? How is it made? Where do we find trans-fats?
○ Hydrogens and carbons on opposite side of double bond
○ Type of unsaturated fat
○ Partially hydrogenated unsaturated fats are how its made
➢What are the major conclusions from this meta-analysis regarding total amount of fat
consumption and serum cholesterol levels and heart disease?
○ Metabolic studies have long established that the type of fat, but not total amount
of fat, predicts serum cholesterol levels.
○
➢Which types of fats have been shown to lower the risk of heart disease most effectively?
○ Replacing saturated fats with poly/unsaturated fats
➢Is there any scientific basis for the low-fat campaign that was promoted for the last
several decades?
○ Not the original one
■In a new one the scientist found a weak positive association between saturated fat intake
and risk of CHD, but a significant and strong positive association with intake of trans fatty
acids.
● Prospective cohort studies and secondary prevention trials have
provided strong evidence that a higher intake of n-3 fatty acids
from fish or plant sources lowers risk of CHD.
➢Is there any strong evidence for a link between egg consumption and risk of heart
disease?
○ No
1. Which types of changes in the diet did they find to be most effective in improving blood
sugar control?
a. substituting carbohydrate and saturated fat with a diet rich in unsat- urated fat,
particularly polyunsaturated fat, was beneficial for the regulation of blood sugar.
2. What are some recommended food sources for improving blood sugar control?
a. consuming more unsaturated fats in place of either carbohydrates or saturated fats will
help improve blood glucose control
b.
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