December 29, 2008
They were some of the most promising medicines of the 1990s - wonder pills that appeared to fight cancer, heart disease and other ailments.
Laboratory tests and initial studies in people suggested that lowly vitamins could play a crucial role in preventing some of the most intractable illnesses, especially in an aging population. The National Institutes of Health gave them the same treatment as top-notch pharmaceutical drugs, investing hundreds of millions of dollars in elaborate clinical trials designed to quantify their disease-fighting abilities.
Now the results from those trials are rolling in, and nearly all of them fail to show any benefit from taking vitamins and minerals.
This month, two long-term trials involving more than 50,000 participants offered fresh evidence that vitamin C, vitamin E and selenium supplements don't reduce the risk of prostate, colorectal, lung, bladder or pancreatic cancer. Other recent studies have found that over-the-counter vitamins and minerals offered no help in fighting other cancers, stroke and cardiovascular disease.
Research has even suggested that, in some circumstances, vitamin and mineral supplements can be unsafe.
Some physicians now advise their patients not to bother with taking the pills and to rely instead on a healthy diet to provide needed vitamins and minerals.
Researchers have identified several reasons why vitamins don't lend themselves to randomized controlled trials. Chief among them is that there is no true placebo group when it comes to vitamins and minerals because everyone gets some in their diet.
Los Angeles Times
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