What can’t dietary supplements do? They prevent cancer, lengthen the life of your joints, and stave off Alzheimer’s. Or at least that’s what it may say on the label. Americans are still a trusting people, and CNN reports that about half of us take some kind of dietary supplement, together spending about a quarter of a trillion dollars annually.
So why is the Fred Hutchinson Cancer Research Center reporting that “In general, there’s no strong evidence that taking a multivitamin increases or decreases your cancer risk”?
You remember that little disclaimer you see a lot on bottles: “This statement has not been evaluated by the FDA”? That’s thanks to legislation that President Clinton signed into law in 1994, allowing companies to market supplements on their recognizance, as it were. When it comes to mixing up existing, approved ingredients, anything goes, and pretty much any claim goes, so long as that little statement is appended.
Companies need prove the safety only of a “new” ingredient, although, as the FDA notes, “manufacturers and distributors are responsible for determining if a dietary ingredient is ‘new’,” in the first place. (As for efficacy, without casting aspersions on company-funded studies, it’s clear that if their conclusions were completely reliable, no one in the world would be suffering from anything.)
The U.S. Food and Drug Administration is mainly concerned that supplements not poison you–and their regulatory authority at this point comes to bear only after you’ve been harmed. In essence, it’s all supplemental fun and games until someone loses an eye. Luckily, you’re protected somewhat by the invisible hand of the market, which dictates that killing off or disabling a lifelong customer base is a terrible idea.
Still, for many in our health-insurance-less age, dietary supplements are the next best thing to medicine. The Hutch’s Dr. Emily White argues that when it comes to cancer prevention, that’s not necessarily so. Fruits and vegetables are, pills and caplets aren’t.
White “spent several years tracking how 38 different supplements impact the health of more than 75,000 study participants,” reports the Hutch. She couldn’t find any cancer prevention from multivitamins. (A 2009 study by the Hutch’s Dr. Marian Neuhouser included “161,000 women and found that taking multivitamins did not affect the likelihood of contracting cancer or cardiovascular disease.”)
It’s a bit like whack-a-supplement, but the Hutch researchers have previously found that neither Vitamin E nor selenium seem to prevent prostate cancer. (Scratch beta carotene and retinyl palmate, as well.) Calcium and vitamin D have no discernible impact on colorectal cancer.
Fish oil is still in the running, but Dr. White’s bottom-line assessment is this: Rather than poring over supplement fine print, “You should be shopping in the produce section instead.” Whatever it is in food that’s good for us, it’s mostly in the food. (NB: If you have a known vitamin deficiency, especially because of a food-related allergy, taking a supplement is a good idea. But without a deficiency, caveat emptor.)