Why You Should Not Stop Taking Your Vitamins
SOURCE: The Huffington Post ~ 10-20-2011
By Mark Hyman, M.D.
Do vitamins kill people?
How many people have died from taking vitamins?
Should you stop taking your vitamins?
It depends. To be exact, it depends on the quality of the science, and the very nature of scientific research. It is very hard to know things exactly through science. The waste bin of science is full of fallen heroes like Premarin, Vioxx and Avandia (which alone was responsible for 47,000 excess cardiac deaths since it was introduced in 1999).
That brings us to the latest apparent casualty, vitamins. The recent media hype around vitamins is a classic case of drawing the wrong conclusions from good science.
Remember how doctors thought that hormone replacement therapy was the best thing since sliced bread and recommended it to every single post-menopausal woman? These recommendations were predicated on studies that found a correlation between using hormones and reduced risk of heart attacks. But correlation does not prove cause and effect. It wasn’t until we had controlled experiments like the Women’s Health Initiative that we learned Premarin (hormone replacement therapy) was killing women, not saving them.
A new study “proving” that vitamins kill people is hitting front pages and news broadcasts across the country. This study does not prove anything.
This latest study from the Archives of Internal Medicine of 38,772 women found that “several commonly used dietary vitamin and mineral supplements may be associated with increased total mortality”. The greatest risk was from taking iron after menopause (which no doctor would ever recommend in a non-menstruating human without anemia).
The word “may” is critical here, because science is squirrelly. You only get the answers to the questions you ask. And in this case, they asked if there was an association between taking vitamins and death in older woman. This type of study is called an observational study or epidemiological study. It is designed to look for or “observe” correlations. Studies like these look for clues that should then lead to further research. They are not designed to be used to guide clinical medicine or public health recommendations. All doctors and scientists know that this type of study does not prove cause and effect.
Why Scientists are Confused
At a recent medical conference, one of most respected scientists of this generation, Bruce Ames, made a joke. He said that epidemiologists (people who do population-based observational studies) have a difficult time with their job and are easily confused. Dr. Ames joked that in Miami epidemiologists found everybody seems to be born Hispanic but dies Jewish. Why? Because if you looked at population data in the absence of the total history and culture of Florida during a given time, this would be the conclusion you would draw. This joke brings home the point that correlation does not equal causation.
Aside from the fact that it flies in the face of an overwhelming body of research that proves Americans are nutrient deficient as a whole, and that nutritional supplements can have significant impact in disease prevention and health promotion, the recent study on vitamins is flawed in similar ways.
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