Best way to get your vitamins? Eat them.

Certainly there are times when it's a good idea to take extra vitamins or other supplements, but these are limited to people in pretty specific populations: for example, during pregnancy, if you are a woman of childbearing age, or if you are following a vegan diet. However, in our well-fed Western culture it's pretty rare to really need to take vitamins.

One of the drawbacks of the last few decade's worth of nutrition research is that with all that we've learned about the importance of specific vitamins, people have become focused on specific nutrients rather than an overall healthy diet. And that's likely the reason that more and more people are taking vitamin supplements, believing that they can enhance their health or even help prevent chronic diseases - heart disease being one example.

Unfortunately, it appears that not only is taking vitamins likely to be unnecessary, it may actually be harmful.

An international team of researchers made use of data collected during the Iowa Women's Health Study, which included diet, health and vitamin intake records of nearly 20,000 postmenopausal women (Arch Int Med 2011;171(18):1625-1633). The study was originally designed to look at the associations between diet and lifestyle factors and the incidence of cancer and lasted over 20 years.

In addition to which vitamins or minerals the participant reported taking, the researchers took into account such variables as age, Body Mass Index, education, whether the participant smoked, whether they had diabetes or high blood pressure, their average caloric intake and even the amount of saturated fat in their diet. For those women who died during the study, the researchers acquired information regarding cause of death and assigned the deaths to one of three types: cardiovascular disease, cancer, or all other causes (not including injury, accident or suicide).

After comparing the supplements taken by those women who died of those three causes with those women who did not die, the researchers found that, generally speaking, taking vitamin supplements had no effect on a woman's risk of death. That said, some supplements stood out: for example, taking calcium appeared to be related to a reduced risk of death, while taking iron, especially as the women got older, seemed to increase the risk of death.

What this means for you

Remember that this study does not establish a cause and effect relationship between taking vitamins and death - but since it takes into account so many variables, the association between certain supplements and risk of death might be a cause for some concern. The take-home message for you is that unless your doctor tells you to take a specific vitamin, chances are you don't need them. Spend your money on eating great food instead.

First posted: October 12, 2011