Healthnotes Newswire (October 12, 2000)—People taking vitamin E supplements have a dramatically reduced risk of suffering heart attacks, according to a report in the current issue of The Lancet.¹

In this latest chapter in the on-again, off-again story of the effect of vitamin E on heart-disease prevention, Israeli researchers found that patients given vitamin E supplements suffered 70% fewer heart attacks than did those given placebo.

The researchers studied 196 patients with a history of heart disease and with kidney failure and dependency on kidney dialysis machines. Subjects were given either 800 IU (international units) of natural vitamin E (d-alpha tocopherol) per day or placebo for an average of 519 days. Participants were chosen for the trial because the combination of kidney failure and a history of heart disease leads to an extraordinarily high risk of suffering a future heart attack. Also, such patients show evidence of unusually high oxidative damage—the very kind of damage vitamin E is likely to protect against.

The amount and the form of vitamin E used in the Israeli trial were identical to the protocol employed by English researchers with many of the subjects in the Cambridge Heart Antioxidant Study (CHAOS).² That trial reported a 77% decrease in nonfatal heart attacks—a figure quite similar to the 70% decline in heart attacks reported in the new Lancet report. Most participants in the present trial (both in the vitamin E and placebo groups) were also given large amounts of folic acid (5–10 mg per day), vitamin B6 (10–250 mg per day), and vitamin B12 (250 mcg per day) to lower blood levels of homocysteine—a marker of heart disease risk. Homocysteine is known to be elevated in most people with kidney failure and many people with heart disease. Most subjects in both groups were also given 500–1,000 mg per day of vitamin C.

The researchers found that, in addition to protecting against heart attacks, vitamin E may also protect against other cardiovascular diseases, including stroke, angina (chest pain from heart disease), and peripheral vascular disease (disease of the arteries in the lower extremities). However, these trends were not statistically significant. These results were achieved even though, by chance, a higher percentage of the vitamin E group smoked cigarettes (25%) compared with the group assigned to placebo (14%). (The effect of taking vitamin E on smokers and nonsmokers was not significantly different.)

The incidence of fatal heart attacks in the new Israeli trial was 43% lower in the vitamin E group than in the placebo group. However, this reduction was not statistically significant. Despite the reduced death rate from heart disease in the vitamin E group, both vitamin E and placebo groups had approximately the same overall risk of dying during the course of the trial—meaning that more deaths unrelated to heart disease and stroke occurred in the vitamin E group compared with the placebo group. However, the increase in noncardiac deaths (which included deaths from a car accident, surgery, and complications following kidney transplantation) may have been due to chance rather than to the use of vitamin E.

Scientists have been hopeful that vitamin E supplements would reduce the risk of heart disease since 1993, when two large, well-respected, preliminary studies reported that people who take vitamin E supplements are at reduced risk for suffering a heart attack.^{3 4} However, not all previous reports have found vitamin E protective under every circumstance. Analyses of the English trial—CHAOS—have frequently mentioned that, although the incidence of nonfatal heart attacks was sharply lower in the vitamin E group, deaths from heart attacks actually increased compared with the placebo group. However, a further analysis of CHAOS data has revealed that this finding was due to chance—most deaths from heart attacks in those assigned to take vitamin E occurred among subjects who failed take the vitamin E supplements as instructed.⁵

An Italian trial⁶ was widely reported by the press as showing that vitamin E supplementation did not protect against heart disease. However that trial did find a reduced incidence of deaths related to heart disease for people assigned to take vitamin E, although no difference in nonfatal heart attacks occurred. In pointing out the differences between the Italian trial and their own, the Israeli researchers noted that the Italians used both a lower dose of vitamin E (300 IU per day) and a synthetic form of vitamin E, compared with the natural form used by the Israelis.

The largest double-blind trial studying the ability of vitamin E to prevent heart attacks found vitamin E to be ineffective.⁷ Scientists are scratching their heads trying to understand the remarkable inconsistencies in the findings of the vitamin E trials. The Israeli researchers point out that trials that have obtained the best results studied subjects with very high risk for heart attacks, while the trials that have come up empty-handed studied people with much lower risk. Possibly, vitamin E is primarily helpful to those at greatest risk. The dramatic, positive results of the Israeli trial may also have occurred because vitamin E prevents the oxidative damage found at such high levels in patients on dialysis. Therefore, the ability of vitamin E to prevent heart attacks in people with normal kidney function may not be as great as the results attributed to vitamin E in the new report.