Shun Multivitamins? They Won't Kill You, But Walk To Farmstand Instead

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Recent studies raise concerns about vitamin supplements
Recent studies raise concerns about vitamin supplements

I used to pop a multivitamin every day. You're just supposed to, right? Then I started paying closer attention to the research, and I dropped them from my morning routine.

My neck gets tired from watching the good-for-you-bad-for-you vitamin pendulum; here's the kind of thing I mean, from October:

Last we heard — last fall, actually — a study of more than 38,000 older women in Iowa brought disturbing news to the millions who take daily vitamins. It found, as NPR reported: “Use of many common supplements — iron, in particular — appeared to increase the risk of dying, and only calcium supplements appeared to reduce mortality risk. The increased risk amounted to a few percentage points in most instances.”

Now comes a somewhat countervailing study: The Journal of the American Medical Association reports that in 15,000 older men, multivitamins do confer apparent benefit, reducing the total risk of cancer by 8 percent.

So what's the bottom line? Dr. Paul Offit, best known for his vaccine research, took an outspoken stance in The New York Times this weekend, and it has been on the most-emailed list since. Headlined "Don't take your vitamins," it says in part:

Nutrition experts argue that people need only the recommended daily allowance — the amount of vitamins found in a routine diet. Vitamin manufacturers argue that a regular diet doesn’t contain enough vitamins, and that more is better. Most people assume that, at the very least, excess vitamins can’t do any harm. It turns out, however, that scientists have known for years that large quantities of supplemental vitamins can be quite harmful indeed.

Offit offers a lucid explanation of how large doses of antioxidants could become too much of a good thing. Uh oh. I contacted Dr. Pieter Cohen, a general internist at Cambridge Health Alliance who researches dietary supplements, for a reality check. Our conversation, edited:

So why is this Paul Offit piece so emailed? What is it telling us that we want others to know?

He’s recommending not to take multivitamins, and we so often hear: Since we can’t eat every day out of our personal gardens, we should make up for it by taking a multivitamin with a nice bucolic image on the label.

But, I think [Paul Offit] overstates the case and is alarmist: He’s saying multivitamins are dangerous and avoid them –

Or is he talking about megavitamins?

Since the editors have titled it “Don’t take your vitamins,” and we generally take multivitamins which are not megavitamins, this would imply to me, ‘Don’t take multivitamins because they are dangerous.’

That’s false. There’s a ton of data: Over 175,000 people have been carefully studied while taking multivitamins, and what the huge database is telling me is that taking your multivitamin won’t kill you. That’s why the headline is misleading, because in fact we know that for the great majority of people, taking multivitamins is not going to kill them.

Wasn’t there recently a big study in which mortality rose among people who took multivitamins?

The largest randomized study of multivitamins came out from the Women’s Health Initiative a few years ago and it appeared to have no effect on mortality. Another large study came out in the journal JAMA from the Physicians’ Health Study last year and did not look at total mortality, only at cancer mortality (and did not increase or decrease it).

Fine, but why even take them if they don’t seem to do me any good?

Now you’re talking. How I see multivitamins is that they provide a false sense of security. There’s zero evidence that they do you good, unless you have a specific medical problem that you need them for. So you’re spending thousands of dollars over a lifetime and giving yourself a false sense of security. And there’s no enjoyment to taking vitamins, you’re not going to gather with your friends on a Friday night and share you favorite multivitamins; it doesn’t bond people like traditional food.

Offit’s other big point is that because of a history of political maneuvers, the whole vitamin industry is shockingly under-regulated.

Offit points to changes in the 1970s; but in fact, every time in the past almost 80 years that the FDA has tried to more tightly regulate or control how much of a vitamin was in a supplement, or what was on the label, there’s been a backlash from industry, and from sellers of vitamins, and from people who want to buy their vitamins, and the backlash has led to more lax standards.

The most dramatic example is the Dietary and Supplement Health and Education Act of 1994, that’s our current regulatory framework. Under this current framework, all supplements, everything sold as a supplement in the United States, is assumed safe, sold as if it were food. And only if the FDA demonstrates a life-threatening risk can the supplement be removed — much as it can act when a Big Mac is contaminated by salmonella.

But if a high dose of vitamin E or vitamin A increases cancer or worsens bone disese, there’s pretty much nothing the FDA can do about it, because the FDA is not tracking who’s taking how many vitamins. If it slightly increases the risk of a subgroup of people — say, smokers — the FDA can’t legally remove that supplement from the market. So there’s really no safety net. There’s no way for the FDA to capture long-term, low-level risks that a consumer is exposed to; it just doesn’t exist. The safety net is Swiss cheese.

But then we start getting these huge studies which suggest that the risk is at least significant enough to measure…

Offit points to old studies that used higher doses than are found in multivitamins. That’s why it’s a little deceptive. He’s pointing to high doses of vitamin E and beta carotene that do increase the risk of cancer and other problems, but those are not doses that are found when we go to CVS and pick up our One-A-Day. That’s why I say it’s not going to kill you.

So say I come into your office as a patient with no special medical need for vitamins. What do you recommend?

People often ask me, ‘Should I take a multivitamin? Do I need it?’ And it’s very straightforward: No, you don’t need it, and and you should not feel guilty about not taking it. You could spend those thousands of dollars on buying higher quality food, and maybe a new pair of sneakers to walk to the farmstand and buy some locally grown produce instead…

Readers, thoughts?

This program aired on June 10, 2013. The audio for this program is not available.

Carey Goldberg Twitter Editor, CommonHealth
Carey Goldberg is the editor of WBUR's CommonHealth section.