Stop taking a multi-vitamin?
July 21, 2013 1 Comment
So, when I was a kid, my mom was way convinced by Linus Pauling of the importance of large doses of Vitamin C– especially for fighting off colds. Turns out they were both wrong. That said, given my poor diet for most of my childhood, I truly think I might have gotten scurvy if not for the vitamin C supplementation. At some point as a young adult, I realized that I was surely missing plenty more nutrients due to my picky eating and started taking a daily multivitamin, which I’ve been doing for at least 20 years or so.
Turns out, I may be increasing risks to my health as a result. At minimum, there’s basically no evidence that multi-vitamins lead to improved health. Paul Offit summarized the evidence in the Atlantic:
Studies have shown that people who eat more fruits and vegetables have a lower incidence of cancer and heart disease and live longer. The logic is obvious: if fruits and vegetables contain antioxidants — and people who eat lots of fruits and vegetables are healthier — then people who take supplemental antioxidants should also be healthier.
In fact, they’re less healthy.
Offit then provides brief summaries of about a dozen or so studies– here’s two particularly compelling ones:
In 2007, researchers from the National Cancer Institute examined 11,000 men who did or didn’t take multivitamins. Those who took multivitamins were twice as likely to die from advanced prostate cancer.
In 2008, a review of all existing studies involving more than 230,000 people who did or did not receive supplemental antioxidants found that vitamins increased the risk of cancer and heart disease.
So, what’s going on? Scientists aren’t sure, but here’s the main idea:
How could this be? Given that free radicals clearly damage cells — and given that people who eat diets rich in substances that neutralize free radicals are healthier — why did studies of supplemental antioxidants show they were harmful? The most likely explanation is that free radicals aren’t as evil as advertised. Although it’s clear that free radicals can damage DNA and disrupt cell membranes, that’s not always a bad thing. People need free radicals to kill bacteria and eliminate new cancer cells. But when people take large doses of antioxidants, the balance between free radical production and destruction might tip too much in one direction, causing an unnatural state in which the immune system is less able to kill harmful invaders. Researchers have called this “the antioxidant paradox.” Whatever the reason, the data are clear: high doses of vitamins and supplements increase the risk of heart disease and cancer; for this reason, not a single national or international organization responsible for the public’s health recommends them.
At this point, I think I’ll finish my current bottle of Target multi-vitamins, but then I’m done. Also, I eat way healthier than I used to and am not so worried about meeting basic nutritional needs. I used to have almost now fruits and vegetables, but now I have pretty much 5-6 servings a day (yay for me). At least for the time being, though, I’m going to keep the kids on the multi-vitamin. Yes, I know I need to try harder to get them to eat healthy, but until we make more progress there I think they need the multis just to meet basic dietary needs.
Anyway, as much as part of me wants to keep taking the vitamins, I very much consider myself an “evidence-based person” and I just cannot deny the weight of the evidence on this.
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