October 17, 2011
Hold it before you pop that vitamin into your mouth! You may not be doing your health a favor by taking your favorite supplement.
We know that one-third of American adults take a multivitamin or mineral supplement regularly – and most of them believe they are improving their health by doing so. But a new study published this month in the Annals of Internal Medicine co-relates certain vitamins and minerals with increased mortality in older women.
The Iowa women’s health study was an ongoing study of over 38,000 women in Iowa followed since 1986. The women were an average age of 62, and were surveyed in 1986, 1997 and 2004 about their multivitamin and supplement use. Sixty-three percent were taking at least one supplement when the study began in 1986; however, by 2004 that number climbed to 85 percent. More than 25 percent of the women studied reported taking four or more supplements on a regular basis.
Mortality in this group of women was tracked from 1986 through 2008. The results of the study are somewhat surprising:
• Several commonly used dietary vitamin and mineral supplements may be associated with increased total mortality risk.
• Specifically the use of multivitamins, vitamin B6, folic acid, iron, magnesium, zinc and copper were associated with increased risk of total mortality when compared with corresponding non-use.
• The increased mortality association seems to be strongest with supplemental iron.
• In contrast to the findings of many earlier studies, calcium seemed to be associated with decreased risk – 9 percent less.
• Some supplements, including beta-carotene, vitamins A and C, and selenium, didn’t appear to affect death risk either way.
Is this data clinically significant?
Maybe, maybe not. The total number of increased deaths in this study was small, so this data may or may not be reproduced in subsequent studies. There were twice as many women in the study on hormone replacement therapy than the normal population, and hormone replacement therapy comes with its own risks. The population was mostly Caucasian, from a rural area, so this data may not apply to other demographics.
But it certainly tells us that we don’t know very much about the long-term effects of various multivitamins and supplements.
So, with all this confusing data, who should be on a multivitamin or mineral supplement? Those who are deficient in certain minerals, or those who have been advised by their doctor to do so.
What should the rest of us do? Vitamins and minerals are not a replacement for eating a variety of nutrient-rich foods. We all need to concentrate on eating fresh foods, fruits and vegetables, and focus on minimizing our intake of (low nutritional value) processed foods. Supplements should be just that – a supplement, and not a replacement, for a healthy diet.
And keep your doctor in the loop on all the vitamins and supplements you are taking, for the latest medical advice based on your personal health.