Antioxidants Don’t Lower Heart Risk
Study Examines Vitamins C, E, Beta-Carotene for Preventing Heart Attack, Stroke
Aug. 13, 2007 -- Vitamins C, E, and beta-carotene are not effective for
preventing heart attacks, strokes, or related deaths, according to one of the
longest studies ever to examine the cardiovascular impact of antioxidant
The study included more than 8,000 women at high risk for cardiovascular
disease who took the vitamin supplements, either alone or in combination, for
close to a decade.
During this time no evidence emerged of an overall benefit for antioxidant
The findings are consistent with other major studies showing antioxidants
and other nutritional supplements to be ineffective for the prevention of heart
disease and strokes, cardiovascular nutrition expert Alice Lichtenstein, DSc,
Some of these studies even found specific supplements to be harmful,
although the latest study did not.
“Right now we are all being very cautious about dietary supplements,” says
Lichtenstein, who directs the cardiovascular nutrition lab at Boston’s Tufts
University. “These supplements don’t seem to have clear advantages in people
who aren’t deficient, and there is a concern that overdoing them may have
Antioxidants and the Heart
Oxidative damage at the cellular level is thought to play an important role
in heart and vascular disease by promoting inflammation. The thinking has been
that antioxidants like vitamin C, E, and beta-carotene could protect against
cardiovascular disease by reducing oxidative stress.
Researcher Nancy R. Cook, ScD, and colleagues from Harvard Medical School
and Brigham and Women’s Hospital in Boston tested the theory in their study,
published in the latest issue of the journal Archives of Internal
A total of 8,171 women were recruited who had had either a heart attack or
stroke or who had at least three cardiac risk factors such as having high
cholesterol, diabetes, or high blood pressure, being a current smoker, and
The average age of the women at recruitment was 60, and they were followed
for an average of 9.4 years.
During this time, the women took either vitamin C, vitamin E, beta-carotene,
a combination of the antioxidants, or placebo. There were 274 heart attacks,
298 strokes, 889 bypass surgeries or angioplasties, and 395 deaths due to
Overall, none of the
vitamins, either alone or in combination, were found to significantly impact
any of these cardiovascular outcomes.
Women who took vitamins C and E did have slightly fewer strokes, but it was not clear if the association was
real or a function of the study design. Also, when participants who didn't take
the assigned supplements regularly were removed from the analysis, there was a
13% reduced risk of any incident of heart attack, stroke, bypass surgery
or angioplasty, or death due to cardiovascular causes linked to vitamin E, but
not for the other supplements studied.
“Overall we found no benefit on the primary combined end point for any of
the antioxidant agents tested, alone or in combination. We also found no
evidence for harm,” Cook and colleagues wrote in the Aug. 13/27 issue of the
Archives of Internal Medicine.
“While additional research into combinations of agents, particularly for
stroke, may be of interest, widespread use of these individual agents for
cardiovascular protection does not appear warranted.”