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Lesson 2 Video 6Observation (epidemiological) studies: studies where the assignment of subjects is not controlled by the investigator, large group of people-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) oRetrospective: 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 oProspective: 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 pastEx: 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)-Interventional Controlled Study : double blinded randomized placebo controlled study (best and ultimate study you can get)oPlacebo response: when people believe the drug will make them get better (psychological)oBlind study : divide group 2 (one gets placebo one gets new drug) and they don’t know which is whichoDouble blind study : researcher doesn’t know which group has which eitheroRandomized : 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 IIVideo 1Vitamin 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 foodoProvitamine 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 Aoso 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)-Benefits:obone grown, reproduction and immune system healthohelps the skin and muous membranes repel bacteria viruses more effectivelyoessential 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?