Is taking vitamins bad for you? So the latest research seems to say. A study following the lives of nearly 39,000 women, median age 61, over a 25-year stretch was published on October 10, 2011 in the Archives of Internal Medicine. The study showed a correlation between seven common supplements and an increased total mortality rate in the study group. Multivitamins, iron, copper, zinc, Vitamin B-6, folic acid and magnesium supplements were all identified as being associated with a slightly higher total mortality risk in the study group. The study’s conclusion reads, “In older women, several commonly used dietary vitamin and mineral supplements may be associated with increased total mortality risk; this association is strongest with supplemental iron. In contrast to the findings of many studies, calcium is associated with a decreased risk.” 1 The slightly increased risk of “total mortality” is cited as 2.4%.
While this latest research study report actually shows a positive correlation between certain supplements and mortality risk, previous studies have been less conclusive. The Women’s Health Initiative conducted a 2009 study that tracked 161,000 post-menopausal women over eight years to ascertain the health benefits of taking vitamin and mineral supplements, with a focus on heart health and cancer. The abstract for that 2009 study concludes: ” After a median follow-up of 8.0 and 7.9 respectively, the Women’s Health Initiative study provided convincing evidence that multivitamin use has little or no influence on the risk of common cancers, cardiovascular disease, or total mortality in post-menopausal women.” 2 This earlier research study shows no measurable benefit of vitamin supplements, but neither does it show a measurable danger from taking them.
Both of these studies fail to answer questions that might help shed light on the findings. Are the women taking supplements just to enhance their health, or have they been prescribed a supplement in the context of illness? Why is calcium an exception? Are some supplements more dangerous than others because of the vitamin or mineral itself, or the environment origin of the supplement, which may include contaminants? How have “multivitamins” changed in composition over the course of the 20-year-long study just completed this month? The 2011 report admits that the study is based on self-reported information. The common shared qualities of the study group were age and gender: older women. How much do unmentioned variables have an effect on the health of the women in the study: diabetes, weight, diet and exercise, cholesterol numbers, blood pressure?
Perhaps the safest conclusion to draw from this latest study is that the research is not yet conclusive for condemning the health effects of vitamins and supplements. Janice Lloyd of USA Today quotes Miriam Pappo, director of clinical nutrition at Montefiore Medical Center in New York. Pappo advises taking this research with a grain of salt and not to stop taking a daily vitamin pill because of it.
Even the 2011 study’s authors are puzzled by the results of the study and recommend more studies to try to clarify the findings. 2011 study author Jaakko Murso suggests more research be conducted to find out more about how vitamins and supplements affect health; this study focuses more on the mortality risks from common causes like cancer and cardiovascular disease.
At this point, the best conclusion might be that more research is needed. The jury is still out on vitamins and supplements. Don’t toss out your daily vitamins just yet.
Sources:
Archives of Internal Medicine, Vol 171, No. 18, October 10, 2011
http://archinte.ama-assn.org/cgi/content/short/171/18/1625
Janice Lloyd, USA Today, Oct. 10, 2011 “Study Flags Risk of Daily Vitamin Use Among Older Women”
Tara Parker-Pope, The New York Times, February 16, 2009. “Vitamin Pills: A False Hope?”
1Archives of Internal Medicine, Vol. 171 No. 18, October 10, 2011, abstract conclusion
2Archives of Internal Medicine, Vol. 169 No. 3, Feb. 9, 2009, abstract conclusion