Two widely reported studies claiming nutritional supplements may be harmful are based on flawed science and reach unsubstantiated conclusions, top research experts tell Newsmax Health.
Gross abnormalities in the way data was handled in both cases has some in the natural health community questioning whether the skewed results stem from sloppy research, or are part of a continuing government and corporate effort to discredit vitamins and supplements.
The separate, unrelated studies were released early last week and quickly made headlines around the world. The first, a two-decade research effort titled the Iowa Women’s Study was published in the Archives of Internal Medicine. It sparked huge media coverage with its explosive conclusion that older women who took dietary supplements — such as multivitamins, folic acid, copper, and iron — risked premature death.
"Based on existing evidence, we see little justification for the general and widespread use of dietary supplements," unless there is a medical reason or deficiency of a particular nutrient, wrote the authors of the study, which tracked 39,000 women for an average of 20 years. The study was performed jointly by researchers from the University of Eastern Finland and the University of Minnesota.
The second study, the Selenium and Vitamin E Cancer Prevention Trial, (SELECT) published Oct. 12 in the Journal of the American Medical Association reports that “dietary supplementation with vitamin E significantly increased the risk of prostate cancer among healthy men.”
"For the typical man, there appears to be no benefit in taking vitamin E, and in fact, there may be some harm," says Dr. Eric Klein, the study’s national coordinator and a prostate cancer expert at Cleveland Clinic.
SELECT, which was funded by the National Cancer Institute, tracked 35,000 North American men from 2001 to 2008. Subjects were placed in four groups: vitamin E and selenium; vitamin E alone; selenium alone; and placebo. Only the group taking 400 IU of vitamin E alone saw an increased risk of prostate cancer, according to the study.
Given the controversial conclusions and the prestigious research organizations and publications involved, mainstream media outlets were quick to run with banner headlines such as “Multivitamins Killing Older Women” and “Vitamin E Boosts Cancer Risk.” But as critics dug into the underlying research data, the conclusions trumpeted in the press were shown to be increasingly — some would say suspiciously — weak.
All of the results of the Iowa Women’s Study are drawn from just three self-reported, sparsely detailed questionnaires submitted by subjects over more than two decades. The unreliable data collection method was not backed up by any significant medical investigation. Perhaps more troubling, the study gave almost no weight to confounding risks factors such as whether the women taking vitamins might have had pre-existing medical conditions, had turned to supplements to help treat other illnesses, were smokers, or whether they were also taking other potentially harmful substances such as synthetic hormones.
“The bottom line is that the researchers have no idea how much vitamins and minerals, and in what combinations, these women actually consumed or why they died,” says Steve Milloy a research and public health policy expert and founder of Junkscience.com, who examined the full study. “To condemn multivitamins with such shoddy statistical inference is absurd.
“This study proves nothing other than shocking and shockingly junky results can get published in an otherwise reputable journal.”
