Adults taking multivitamins don't live longer than those who get their nutrients from food alone, according to a US study that found they in fact appear to have slightly higher death rates. About half of adult US residents take dietary supplements, and the industry now boasts of annual sales as high as $20 billion. Yet research suggests that some of the largely unregulated substances, such as vitamins A and E, could be harmful in high doses, according to an editorial published with the study in the Archives of Internal Medicine. “There is very little evidence showing that common dietary supplements would be beneficial in prevention of major chronic diseases,” said Jaakko Mursu of the University of Minnesota in Minneapolis, who worked on the study. “Unless you are deficient, there is hardly any reason to take them,” he told Reuters Health. Mursu and his colleagues used data from nearly 39,000 older women who participated in the Iowa Women's Health Study and filled out questionnaires. The survey asked about use of multivitamins, vitamins A, C, D and E as well as beta-carotene, B vitamins and minerals such as calcium, copper, magnesium, selenium and zinc. During the study, supplements became increasingly popular. Between 1986 and 2004, the proportion of women who said they took one or more jumped from 63 percent to 85 percent. Only calcium supplements were linked to a lower risk of death over 19 years of follow-up, with 37 percent of users dying compared to 43 percent of non users. That link held up even after considering that women taking supplements had a healthier lifestyle than the rest. Mursu said he expects that his findings will be true for men as well, adding that they jib with earlier research hinting dietary supplements do little good in Western countries where vitamin deficiency is not common.
