Natural Foods Merchandiser

Study's conclusion misses the true story

To the Editor:
In the article "Recent supplement science a mixed bag" in the February issue of The Natural Foods Merchandiser, a mention was made of a vitamin E study, quoting researchers that, "Long-term use of vitamin E supplements did not provide cognitive benefits among generally healthy older women." This study included about 5,000 women from the original Women's Health Study. While the quote is true, it does not accurately capture the reality of the data.

I find this conclusion to be a very inaccurate summation of the data. Vitamin E did show benefits in the women who were actually taking the vitamin, which many simply failed to do. Including noncompliant study subjects in the data resulted in a misleading conclusion.

Ignoring the complexity of the data and even the researchers' own cautions about the robustness of their conclusions in order to produce a brief written or broadcast "sound bite" for a news report frequently results in oversimplistic and inaccurate reporting. It is also all too common that a careful analysis of the research data may even contradict a study's main conclusions, making the ensuing media reports all the more misleading. This appears to be the case with this particular study. The researchers' own data has elements that contradict the conclusion stated above.

  • When results were adjusted to exclude noncompliant women (23 percent to 25 percent of the study population), there were benefits noted for those who actually took the vitamin E.
  • Cognitive testing was done for only the last four years of a 9.6-year-long study, ignoring any possible improvements in the vitamin E group over the initial 5.6-year period.
  • Previous successful models were for mice given vitamin E from a young age, but not for mice given the vitamin only when elderly. Most women were in their 60s when this trial began.
  • Previous successful human trials lasted more than 10 years, but this study admittedly did not.
  • There was a significantly lower risk of substantial decline in at least one cognitive measure for the people taking vitamin E.
  • Women who eat less dietary vitamin E did have less cognitive decline if they were in the group taking it as a supplement.
  • There was also a benefit shown for vitamin E among the women who did not exercise.
  • Another group that benefited from taking vitamin E was nondiabetic women.
  • The researchers admit that the dose used in this study is lower than was used in previous trials, making positive results more unlikely.
  • The authors also admit that other forms of vitamin E were not measured in this study, nor levels of other supporting antioxidants other than dietary vitamin E.

The researchers even caution against putting too much reliance on their own analysis: "However, these analyses themselves may be inherently biased and thus should be interpreted with caution." It appears that the researchers were correct in cautioning that their conclusions may be questionable.

It is dangerous to base health decisions on a one-line conclusion from a study with?out looking at details of the study finding benefits for specific populations and admitted limitations of the study. If I were the researcher, my conclusion for this study would have reflected that taking vitamin E was shown to be protective to those women who took it; a far different conclusion than was written.

People deserve more careful discuss?ions and analysis of research data in order to be able to make informed health choices. Sadly, this study and the subsequent reporting on the study have failed to convey some useful and accurate information, and may even lead women away from taking an essential vitamin that showed evidence of being protective of mental function when taken as directed.

Neil E. Levin, CCN, DANLA Board-certified clinical nutritionist Nutrition Education Manager NOW Foods Bloomingdale, Ill.

1. Kang JH, et al. A Randomized Trial of Vitamin E Supplementation and Cognitive Function in Women. Arch Intern Med 2006;166:2462-8.

Natural Foods Merchandiser volume XXVIII/number 4/p.14

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