13 Is there a role for prescribing antioxidant
vitamins to patients with coronary artery disease?
If so, who should get them, and at what dose?
Peter Clifton
Three large prospective studies have shown that vitamin E
users have a 40% lower rate of coronary artery disease. At least
100 IU/day of supplement is required to gain benefit. However,
one large study in postmenopausal women showed no benefit
from vitamin E supplementation, but high dietary vitamin E
consumption reduced the risk by 58%.
At present there are only two intervention studies in patients
with coronary artery disease available to guide therapeutic
decisions. The CHAOS study^1 used 400 or 800 IU/day while the
ATBC study^2 used 50 IU/day. Both studies showed that vitamin E
does not save lives in patients with coronary artery disease and
that it may increase the number of deaths. Both studies also agree
that non-fatal myocardial infarctions are reduced significantly, by
38% in the ATBC study and by 77% in the CHAOS study, with a
53% reduction in combined events in the latter study. In the
CHAOS study of 2002 patients, 27 heart attacks were prevented at
the expense of 9 additional deaths (albeit statistically non-signif-
icant) while in the ATBC study the 15 fewer non-fatal heart attacks
were balanced by 15 additional cardiovascular deaths. In the latter
study it could be argued that the low dose of vitamin E used did
not prevent myocardial infarction but when one occurred it was
more often fatal. Until more compelling evidence is available the
potential adverse effect of vitamin E does not outweigh the benefit
of fewer non-fatal myocardial infarctions. Patients should be
advised to eat diets rich in fruit and vegetables instead..
RReeffeerreenncceess
1 Stephens NG, Parsons A, Schofield PM et al. Randomised controlled
trial of vitamin E in patients with coronary disease: Cambridge Heart
Antioxidant Study. Lancet1996; 334477 : 781–6.
2 Rapola JM, Virtamo J, Ripatti S et al.Randomised trial of alpha-
tocopherol and beta-carotene supplements on incidence of major
coronary events in men with previous myocardial infarction. Lancet
1997; 334499 : 1715–20.