Study of vitamin E leads to 'cautious optimism'

On Call

April 30, 1996|By Dr. Simeon Margolis | Dr. Simeon Margolis,Special to The Sun

In a recent column, you pointed out that three different studies have shown lack of benefit from taking beta carotene. I have coronary heart disease and have been taking an anti-oxidant pill containing beta carotene, vitamin E and vitamin C. Is there any new information on whether either vitamins E or C prevents heart attacks?

While no recent studies have examined the effects of vitamin C, a report in the March 23 issue of The Lancet describes results from the first clinical trial of vitamin E, which followed patients for about 17 months, taking either a placebo or large amounts of the vitamin. This study enrolled men and women with coronary artery disease (CAD), proven by angiography. Nine hundred sixty-seven patients received daily placebo capsules, and 1,035 patients were randomly assigned to vitamin E (half got 400 IU and half 800 IU, daily). Similar blood levels of vitamin E were achieved with either dose.

The good news is that during this period the number of nonfatal heart attacks was reduced very significantly, by 77 percent. The bad news is that there was a slight increase in the percentage of patients who had fatal heart attacks (2.6 percent in those on vitamin E, 2.4 percent in those on placebo) and in the percentage of overall deaths (3.5 percent in those on vitamin E and 2.7 percent in those on placebo).

It is important to understand that the slightly greater numbers of deaths from heart attacks and all causes are not statistically significant, and therefore do not indicate a risk from taking vitamin E.

Most deaths occurred within the first seven months of the study and, for example, the five deaths from colon cancer were most certainly unrelated to taking vitamin E. On the other hand, the vitamin E did not appear to prevent deaths from heart attacks in the relatively short period of followup in this rather small study.

One reaction to the results of this study is cautious optimism for a protective effect of vitamin E against CAD. A leader in the field of anti-oxidant research, Dr. Daniel Steinberg, has suggested that anti-oxidants would have their greatest beneficial effects on the earliest stages of the atherosclerotic process that causes CAD. If his idea is correct, vitamin E supplements would exert minimal effects on patients with established CAD (like the ones in this study), and might require a number of years before having a detectable impact on the development of CAD in initially healthy individuals. The final word on the effects of vitamin E on CAD will have to await completion of several large trials presently in process.

Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine.

Pub Date: 4/30/96

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