Lesson 2
Video 6
Observation (epidemiological) studies: studies where the assignment of subjects is not
controlled by the investigator, large group of people
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Case control studies: compare people with a specific condition tp other who are
otherwise similar except for that condition (cancer vs without cancer – what may have
been responsible)
o
Retrospective: problematic cz you have to go back (what do you eat, what’s your
diet, did you smoke)
-
Cohort Study: study of a group of people over a long period of time to determine which
factors may be associated with the appearance of a specific condition, before the
condition has developed and you follow them for a long time
o
Prospective: stronger study, going ahead, more valid than case control, you don’t
have to the problem of people having to remember what they did in the past
Ex: EPIC study : relationship between diet and cancer; increase fruits and
vegetables reduce cancer? wasn’t proven
Epidemiological studies give the information about the relationship or association between to
two factors = correlation. It does not give us causation for that we need:
Intervention Study: assignment of subject is controlled by investigator (more focused and
studied)
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Interventional Controlled Study : double blinded randomized placebo controlled study
(best and ultimate study you can get)
o
Placebo response: when people believe the drug will make them get better
(psychological)
o
Blind study : divide group 2 (one gets placebo one gets new drug) and they don’t
know which is which
o
Double blind study : researcher doesn’t know which group has which either
o
Randomized : people in the two groups are totally random ( no other factors will
come into the picture)
Meta Analysis:
-
Pools epidemiological studies or a bunch or randomized/interventional studies to get a
good result / conclude
Vitamins II
Video 1
Vitamin A
-
Discovered my
Elmer Mccloum
: fat soluble factor A that was required for rat. Animals
fed butter fat and egg yolk thrived and those on lard and olive oil died. Why? they had
Vitamin A (many interchangeable compounds/ different forms)
-
Found in animal foods (like liver) but you don’t have to eat animal food
o
Provitamine A (
Cartenoids
) give rise to Vitamin A in the body
-
1 IU (international units) = to 0.3 mg of retinol(preformed vitamin A in meat) or 0.6 mg
of beta carotene= precursor of Vitamin A
o
so the amount of Vitamin A you get is the same whether from retinol or beta
cartnene ( because you need a large intake of beta carotene than retinol)
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Benefits:
o
bone grown, reproduction and immune system health
o
helps the skin and muous membranes repel bacteria
viruses more effectively
o
essential to healthy visions, and may slow down declining retinal function in
people with
retinitis pigmentosa
-
Night vision is a give a way of deficiency in Vitamin A so eating carrots would do the job
-
Affects many children (blindness, death cz of immune function) over 600 thousands
every year in developing contries
-
How to increase intake of Vitamin A?
