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.
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. http://annals.org/article.aspx?articleid=1767855
Guallar et al. 2013. Enough
is Enough: Stop Wasting Money on Vitamin and Mineral Supplements. Annals of
Internal Medicine 159(12):850-851. http://annals.org/article.aspx?articleid=1789253
Singal et al. 2013. Daily
Multivitamins to Reduce Mortality, Cardiovascular Disease, and Cancer.
Canadian Family Physician 59:847. http://www.cfp.ca/content/59/8/847.full
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