By Patricia J. Sulak, MDDudley P. Baker Endowed Professor, Research and Education in Obstetrics and Gynecology, and Medical Director, Division of Research Department, Obstetrics and Gynecology, Texas A&M College of Medicine, Scott & White Clinic/Memorial Hospital, Temple, TX
Are any readers of this blog NOT on a vitamin, mineral, or other type of supplement such as glucosamine/chondroitin or omega fatty acids? Among the elderly, use of supplements has increased dramatically over the past two decades. An estimated $20 billion is spent annually on these products. While originally thought to be helpful and not harmful, high doses of certain dietary supplements have been shown to have no benefit and sometimes increase health risks. The latest study to look at this issue was published in October of last year in the Archives of Internal Medicine (Mursu J et al. Arch Intern Med. 2011;171:1625-1633).
The aim of this study was to assess the relationship between supplement use and total mortality rates in older women in the Iowa Women’s Health Study. A total of 38,772 women in Iowa aged 55 to 69 years (average 61.6 years) were surveyed in 1986 regarding a multitude of vitamins and minerals. They were surveyed again in 1997 and in 2004 with data collection through 2008 for a mean of 19 years of follow-up.
After correcting for several potential confounding variables, the results of this study call into question some of the current recommendations and personal supplement use. Most of the supplements studied were NOT associated with a reduced mortality in this prospective cohort of older women. In fact, several commonly used vitamin and mineral supplements were associated with a HIGHER risk of mortality, including multivitamins, vitamin B6, and folic acid as well as the minerals iron, magnesium, zinc, and copper. Importantly, supplemental iron was strongly and dose dependently associated with increased total mortality risk. While calcium was associated with reduced mortality, there was no such benefit associated with vitamin D use.
What’s the conclusion of the authors of this study? They see “little justification for the general and widespread use of dietary supplements.” They also recommend that they be used only when indicated such as symptomatic nutrient deficiency disease. What’s my take? Well, I’m turning 60 years old this year and have decided to stop taking my daily multivitamin. Doesn’t look like it does any good and may be doing harm.