Monday, September 23, 2013

Bad Studies Can Be Hazardous to Your Health

~Jack Challem

In our 24‐hour news cycle, headlines are written to shock and scare, and most reporters don’t have the grasp of medicine needed to critically evaluate whether a study is valid or not and publication in a medical journal is no assurance of research quality.

That’s something to consider when you see negative reports on dietary supplements. For example, a recent article in the Archives of Internal Medicine claimed that older women who took a variety of supplements‐including multivitamins‐ had a greater risk of death from disease. But the conclusions drawn from this article were suspect, at best.

For one thing, the Archives study had serious flaws. The subjects were asked to remember, on three different occasions over a span of almost 20 years, which supplements they had taken. This type of data collection is notoriously inaccurate. After all, do you remember exactly what you took years ago? And would something you took 20 years ago actually cause your death today? It’s doubtful.

The researchers also ignored the fact that older people have a higher risk of death simply because of their age, their greater likelihood of having serious age‐related diseases, and their likely use of multiple prescription drugs with attendant side effects.

Strike Two

The very next day, a report in the Journal of the American Medical Association found that men who had taken Vitamin E supplements had a slightly greater risk of developing prostate cancer  than men who didn’t take the vitamin. Here we go again.

First, the Vitamin E used in the study was synthetic, which has very different properties than the natural form. That alone could account for the result.

Second, the diagnoses of prostate cancer were made years after the men had
stopped taking Vitamin E, which would suggest that some other cause or
combination of causes. After all, our lives are filled with thousands of variables that
could skew any study’s results.

Keeping Perspective

But perhaps skewed results shouldn’t surprise us. One of the brightest minds in science, John P.A. Ioannidis, MD, has shown that human studies are rife with biases ‐ financial, professional, and so on. And an editorial in Nature noted that editors and reviewers often don’t exercise a lot of critical judgment in the studies they select for publication.

I would add one more criticism: Studies generally test “one-size-fits-all” medicine ‐ using one or two drugs or supplements to treat a particular condition among a variety of people. Supplements (or any kind of treatment) really should be tailored to the individual.

When you look at the tens of thousands of studies published on vitamins, it becomes clear that the vast majority show direct health benefits. After all, vitamins are essential nutrients. At worst, some studies show no  benefit. One leading researcher told me years ago that it’s important to look at the totality of the research and not to put a lot of weight on one or two studies that don’t make sense.

In sum, these negative reports made for great headlines, but very poor science.

Article courtesy of Better Nutrition Magazine Dec. 2011, All Right Reserved. 

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