Friday, January 24, 2014

Drop the Vitamins and Eat a Fish

It’s the beginning of a new year, and many of us are still optimistically clinging to our New Year's resolutions. But beware…. If any part of your resolution includes taking daily vitamin and mineral supplements, scientists now think that you may be doing more harm than good.

Photo credit: The IHC Group

Over the past year, several research groups have reviewed studies concerning the effects of vitamin supplementation. Each group concluded that for most people in developed nations, there is no benefit. Instead, they found that supplements could even have negative effects. For individuals already at risk of developing lung disease (smokers and asbestos workers), for example, taking beta-carotene clearly results in higher incidence of lung cancer. High doses of other vitamins can also contribute to kidney stones.

Photo Credit: Paolo Neo / Wikimedia Commons

But don’t feel bad. You aren’t the only one who didn’t get the memo. More Americans are taking supplements now than ever before. Nearly 4 out of every 10 people (40%) report taking daily multivitamins, up from 30% in the early 1990’s and another 14% of the population reports taking a variety of other supplements. All in all, Americans are spending over $28 billion a year on dietary supplements when there isn’t even any evidence that they do any good. The trend is similar in Canada and many European countries.

Apart from vitamin E (which imparts no benefit) and beta-carotene (bad for smokers), the effects of many vitamin supplements are not exactly clear. Studies often show no effect or provide evidence that contradicts other similar studies. Furthermore, when the research does yield conclusive results, the benefit of vitamins are usually so low that they aren’t worth taking anyway.

Photo credit: TCS Aesthetics Central

One reason that the science on vitamin supplements is so inconclusive is that no one really knows how much is best for us. Without knowing what optimum vitamin levels are, it becomes impossible to tell whether our supplements are getting us to those optimum levels or whether they’re just a drop in the bucket. Most studies are also on older cohorts, 50 or 60 years old, and only test supplementation over a few months to years, so it’s hard to know for sure whether the results would be the same for younger individuals or over longer periods of time.

One exception is vitamin D, especially D3. Although the research is nowhere near definitive, this is the one vitamin supplement that has some real potential for improving your health. Instead of spending $30 or $40 a year on pills, though, there are plenty of ways to incorporate natural sources into your diet. Fatty fish like salmon and tuna,  for example, are good sources. Sardines and mackerel, though often overlooked, are also a good a place start and more eco-friendly. For vegetarians, eggs are relatively high in vitamin D, as are a variety of enriched foods (milk, orange juice, cereals, tofu).

Lemon-Garlic Sardine Fettuccine, Photo credit: Raincoast Trading

So what does all this mean for you? Well, with regular visits to your primary physician, it means that there really isn’t any reason to spend your hard-earned money on supplements. It’s true that vitamins can be useful in the treatment of certain diseases, but they won’t likely keep you from getting sick in the first place. If you’re a smoker, it also means that you’ll actually be better off avoiding supplements high in beta-carotene. You might even consider cutting back on carrots and sweet potatoes if those are regular in your diet.

Sources and Further Reading:

Fortmann et al. 2013. Vitamin and Mineral Supplements in the Primary Prevention of Cardiovascular Disease and Cancer: An Updated Systematic Evidence Review for the U.S. Preventive Services Task Force. Annals of Internal Medicine 159(12):824-834.

Guallar et al. 2013. Enough is Enough: Stop Wasting Money on Vitamin and Mineral Supplements. Annals of Internal Medicine 159(12):850-851.

Singal et al. 2013. Daily Multivitamins to Reduce Mortality, Cardiovascular Disease, and Cancer. Canadian Family Physician 59:847.

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