Based on a perusal of the vitamin section of most drug stores, you’d think Americans need a lot of vitamins. And almost 50 percent of adult Americans reported taking some dietary supplement, according to the most recently published data in the 2009-2010 National Health and Nutrition Examination Survey (NHANES). People take specific vitamin supplements, of course — B, C, D, E and so on — and if taking one vitamin at a time is too much, one-a-day multivitamins abound, designed for each specific life circumstance. (Are you an active man over 50? Support your cell health with extra selenium!)
Many medical studies show positive health effects from higher vitamin levels. The only problem? These studies often can’t tease out the effect of the vitamins from the effect of other factors, such as generally healthy living. Studies that attempt to do this typically show no impact from vitamin use — or only a very tiny one on a small subset of people. The truth is that for most people, vitamin supplementation is simply a waste of time.
To get a little more concrete — and to understand how we got to that endless row of vitamins at CVS — it’s useful to look at a couple of examples: vitamin D and vitamin E. These are among the most popular vitamin supplements: In the 2009-2010 NHANES, 34 percent of adults reported taking vitamin D supplements and 30 percent reported taking vitamin E.
One can find plenty of support for this supplementation behavior in the medical literature. A recent review identified 290 observational studies on vitamin D. For the most part, these studies measure the amount of 25-hydroxy vitamin D — the marker of vitamin D concentration — in participants’ blood and analyze the relationship between that concentration and various measures of health.
For the rest of the story: http://digg.com/video/this-might-make-you-feel-guilty-about-opening-a-soda