“This study is a classic example of scientific reductionism being used to fulfil a particular need,” said Robert Verkerk PhD, the Alliance for Natural Health International (ANHI) executive and scientific director.
“In this case, it’s supplement bashing…Our view is that the self-reporting questionnaires, and lack of any supporting data on nutrient status of the study’s subjects, means that the majority of the trends emerging from the adjusted data on which the study’s conclusions were based are likely to be anomalous.”
Dr Verkerk pointed to the positive findings for calcium supplementation as, “findings from much more robust studies”.
The UK Health Food Manufacturers' Association (HFMA) scientific adviser, Dr Michèle Sadler questioned the causality highlighted by the researchers.
“This type of study only demonstrates an association and does not tell us whether taking supplements caused these particular effects,” said Dr Sadler.
“The study has many other limitations including the unknown, longer term health status of women taking the supplements, which is more likely to be linked to mortality than the supplements themselves.”
“It’s a case of which comes first, the chicken or the egg, and raises the question of how many women were taking the supplements because of ill health. How such a wide range of essential nutrients is supposed to have these effects is another unanswered question.”
Dr Verkerk said the research was flawed in design.
“Another very important point is that many factors were not controlled for, and these likely contributed to uncontrolled sources of variation and confounding that were simply ignored. Among these is the crucial issue of the forms of nutrients taken, none of which were recorded in questionnaires.”
“For example, there are several studies that suggest that long-term use of high doses of synthetic vitamin E, beta-carotene and folic acid may increase the risk of death, these generally having at least some plausible mechanisms. But, where the natural forms are consumed, especially where these nutrients are obtained from dietary sources, quite the reverse is found.”
He said the researchers had, “knowingly, or unknowingly, played into the hands of the pharmaceutical industry, the single biggest contributor to, and controller of, medical research.”
The University of Minnesota researchers led by Jaakko Mursu, PhD, found, “several commonly used dietary vitamin and mineral supplements, including multivitamins, vitamins B6, and folic acid, as well as minerals iron, magnesium, zinc, and copper, were associated with a higher risk of total mortality.”
See NutraIngredients-USA.com coverage of the research here.
Source: Archive of Internal Medicine
2011, Volume 171, Issue 18, Pages 1625-1633
“Dietary Supplements and Mortality Rate in Older Women: The Iowa Women's Health Study”
Authors: J. Mursu, K. Robien, L.J. Harnack, K. Park, D.R. Jacobs Jr
Editorial: Archive of Internal Medicine
2011, Volume 171, Issue 18, Pages 1633-1634
Vitamin and Mineral Supplement Use in Relation to All-Cause Mortality in the Iowa Women's Health Study:
Comment on "Dietary Supplements and Mortality Rate in Older Women"
Authors: G. Bjelakovic, C. Gluu