Physicians' Health Study II finds no magic bullet for averting cardiovascular disease

Vitamins E and C have other important benefits, says CRN

In response to the Physicians' Health Study II, to be released at the American Heart Association's Scientific Sessions and to be published in the November 12 issue of the Journal of the American Medical Association, which examines the effects of vitamin E and C supplementation on cardiovascular events in male physicians, the Council for Responsible Nutrition, the leading trade association representing the dietary supplement industry, issued the following statement.

Statement by Andrew Shao, Ph.D., vice president, scientific and regulatory affairs, CRN: "We commend the researchers for undertaking this important prevention trial which sought to confirm positive results demonstrated by earlier observational trials on these antioxidant vitamins. Although the results did not demonstrate an overall benefit, the results also do not discount the earlier epidemiological data showing that people with high intakes of vitamins E and C may have a lower risk of cardiovascular disease. Nutrition research is extremely complex, and doesn't always provide clear cut answers. This study raises an interesting set of scientific challenges as to why the benefits found in observational studies have not been confirmed in this kind of trial.

From a consumer's point of view, it can be frustrating to have more questions than answers, but for scientists, this can be intriguing. The truth is, we don't have conclusive scientific evidence in the form of randomized, controlled trials that demonstrate exactly how to prevent cardiovascular disease. We do know there are some well-known practical approaches, like not smoking, maintaining a healthy weight, consuming a diet with a variety of foods, regular exercise, seeing your physician, and responsible use of vitamin supplements. Consumers should not take vitamins expecting that vitamins alone will prevent cardiovascular disease, but they should continue to take vitamins for the general health benefits they provide."

Statement by Annette Dickinson, PhD, consultant and past-president, CRN:

"This important study is another in a series of clinical trials that generally have failed to confirm hopes of identifying a strong preventive effect of vitamin E, vitamin C or other antioxidants in relation to cardiovascular disease. The trials were undertaken because of strong positive evidence from epidemiological studies, and the reasons for the different results in clinical trials remain to be clarified. Potentially relevant factors pointed out by the authors of this study include dose, duration, and combinations of nutrients.

With regard to the possible effect of vitamin E on increased risk of hemorrhagic stroke, this has been a subject of discussion ever since the ATBC trial of male smokers in Finland reported such an effect in 1994 with a dose of only 50 IU of vitamin E. Such an effect was not seen in numerous other trials using higher levels of vitamin E (300 to 600 IU), but was observed in this study using 400 IU every other day (equivalent to 200 IU per day). The absence of such an effect in studies with higher doses raises the question whether this occurred by chance.

These results do not of course negate other evidence of benefits for vitamin E and vitamin C for other conditions, including immune function, mental acuity, and eye health. Consumers would be well advised to ensure adequate intakes of all essential nutrients through a good diet plus use of a multivitamin, and selected other nutrients including vitamins E and C, vitamin D, calcium, and EPA and DHA omega-3 fatty acids."

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