Two recently published studies look at the casual use of multivitamins and supplements in a totally different light than previous studies.

In my clinical practice, I have only recommended multivitamins and supplements to those that I suspected weren’t getting their full daily doses through diet. However, many more patients consume a healthy daily diet.

When such patients inform me of their daily multivitamin or supplement use, I tend to be reluctant in making any recommendation for or against them, except in a selected number of special circumstances. This is for two reasons.

First, I do not have sufficient data to make a positive recommendation since I realize that the extra doses are not helping to supplement any deficiencies. Second, I also do not have any data to conclusively support that taking a daily multivitamin or supplement would harm my patients except in special circumstances where, for example, if a man at risk for heart disease was consuming iron supplements without a documented deficiency. This is because we know that iron accumulation can lead to higher incidence of heart disease. As a result, I let the patient be the best judge in most such situations.

But like it or not, that is all about to change!

In a study published by the Archives of Internal Medicine, the researchers tracked nearly 39,000 women for an average of 19 years. They found a small increase in the risk of death among older women who took dietary supplements compared with those who didn't. The study makes it clear that several commonly used dietary vitamin and mineral supplements may not just be useless but actually gradually contribute to a higher risk of mortality. The association was found to be strongest with supplemental iron.

In another study published by the Journal of American Medical Association, authors studied 35,533 healthy men over ten years, looking at whether vitamin E or selenium would decrease the risk of prostate cancer. They found that dietary supplementation with vitamin E significantly increased the risk of prostate cancer among healthy men. An extended analysis showed that healthy men with an average risk of prostate cancer who took a common dose and formulation of vitamin E (400 IU/d) were observed to have a 17% increase in prostate cancer incidence.

These studies add to the growing evidence demonstrating that certain supplements and antioxidants, such as vitamin E, vitamin A, and beta-carotene, can be harmful. Based on existing evidence, there seems to be little justification for the general and widespread use of dietary supplements unless a specific medical reason or deficiency of a particular nutrient exists in a patient.

However, according to estimates, at least half of U.S. adults take vitamins, minerals, or other supplements. As a result, consumers spent about $11.8 billion on vitamins and minerals last year. In fact, stock for Vitamin Shoppe Inc. was recently upgraded due to recent announcements demonstrating that their earning was up 64.3% from the year earlier quarter. Net income for Vitamin Shoppe Inc. rose to $11.9 million (40 cents per share) vs. $7.2 million (25 cents per share) in the same quarter a year earlier.

In the United States, dietary supplementation has shifted from preventing deficiency to trying to promote wellness and prevent diseases. The supplement industry has been widely successful in having the consumers believe that vitamin and mineral supplements are safe and use them without the supervision of their physicians. As data regarding the adverse effects of dietary supplements becomes available, you can rest assured that there will be a major push back from the industry in order to minimize the financial damage that can result from such data. Therefore, it is extremely important that policy makers and regulatory agencies must ensure that any such products on the market are consumed in a safe and responsible manner.

I can no longer recommend the use of vitamin and mineral supplements as a preventive measure, to my patients who do not have a known deficiency. So now, when a patients who are consuming a normal healthy diet and are devoid of any nutritional deficiency inform me of their daily multivitamin or supplement use, I am going to be asking most of these individuals to stop taking their vitamin supplements.

Rahul Gupta, MD, MPH, FACP, is a Clinical Assistant Professor of Medicine at West Virginia School of Medicine; and Health Officer and Executive Director of Kanawha Charleston Health Department, both in Charleston, WV. He is an internist with a special interest in infectious diseases, HIV/AIDS, public health, and health policy.

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