The study examined the results of 18 randomized trials that followed more than 57,000 participants for an average period of almost six years. When the results of all these studies were analyzed, they revealed that an average daily intake of about 500 International Units (IU) of vitamin D was associated with a 7 percent reduction in deaths from all causes.
Unfortunately, the Archives of Internal Medicine analysis does not prove that vitamin D supplements offer a longer life. What is needed next is a randomized trial that compares people who take vitamin D or a placebo for a number of years. There is some evidence that deficiencies of vitamin D are associated with an increased risk of diabetes and cancer, but these studies are not conclusive.
People usually need to take vitamin D supplements because getting enough from foods is almost impossible. Most of us also don't have the time or the opportunity to get out in the sunshine long enough to get ample vitamin D — even though just 10 minutes daily during the peak hours of sunlight does the trick.
When I first read about this study, I assumed that its touted 7 percent drop in deaths was probably too small to persuade anyone to take vitamin D. I was surprised, then, when my wife said that reading an article in our local newspaper convinced her to start taking vitamin D supplements — nevermind that I had been trying without success for a number of years to convince her to take a daily vitamin D pill!
Even if it doesn't lengthen your life, or does so by only a little, a vitamin D supplement offers considerable benefits with little risk or cost. In one study, for instance, vitamin D reduced the number of falls in frail elderly patients by improving their postural balance. Thus, vitamin D can lower the likelihood of bone fractures by improving both bone strength and balance.
The optimum dose of vitamin D is not known, but excessive amounts can raise blood calcium levels enough to cause toxic effects like loss of appetite, excessive thirst and urination, nausea, vomiting, and difficulty concentrating.
The National Academy of Sciences has recommended an upper daily limit of 2,000 IU of vitamin D. I usually recommend a daily intake of at least 1,200 mg of calcium (also extremely difficult to obtain without a supplement) and 800 IU of vitamin D for both men and women over the age of 50.
And, last, I heartily agree with the statement, attributed to one of the study's authors, that you should probably get rid of all the other vitamins in your medicine cabinet.
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This article was written by Yahoo! Health expert Simeon Margolis, M.D., Ph.D. Copyright 2007. |
