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Carotene, Vitamin E Don't
Prevent Heart Attacks
Excerpt
By Anthony J. Brown, Reuters Health
Having high levels of vitamin E or beta-carotene
(and compounds like it) is no guarantee that you won't have a
heart attack, new research shows. In fact, high levels of one
type of vitamin E -- known as gamma-tocopherol -- may actually
increase the risk.
Because these chemicals are antioxidants,
it has been thought that they may protect against the formation
of plaque that can block arteries, by preventing the oxidation
of LDL ("bad") cholesterol. Although several studies have examined
the link between beta-carotene and heart disease, relatively few
have looked at the effects of other so-called carotenoids.
To look into the question, Dr.
Jing Ma from Harvard University in Boston, and others, turned
to the Physicians' Health Study, which began in 1982 and followed
participants for up to 13 years. The researchers compared the
levels of carotenoids and tocopherols in the blood of 531 men
who later had a heart attack with those of a control group of
531 similar men who did not have a heart attack.
Blood levels of five major carotenoids
were measured, as well as levels of retinol, alpha- tocopherol
and gamma-tocopherol.
"Based on the antioxidant hypothesis,
we expected people with high levels of these compounds to be at
low risk for developing heart disease," Dr. Ma told Reuters Health.
"But, this is not what we found."
Overall, there were was no evidence
that the carotenoids or tocopherols protected against heart attacks,
the team reports in the American Heart Association's journal,
Circulation.
However, among current and former
smokers, higher levels of beta-carotene did lower the risk of
a heart attack.
On the other hand, high gamma-tocopherol
levels were actually linked to an increased risk. But gamma-tocopherol
itself may not actually be harmful, Ma noted. "Gamma-tocopherol
may simply represent a marker for trans-fat intake," which is
known to up the risk for heart disease.
"These findings should not discourage
people from eating fruits and vegetables, as there are probably
other components present that protect against heart disease,"
she stressed. "The bulk of evidence still supports a beneficial
effect for eating such foods."
SOURCE: Circulation, August 19,
2003.
Reference
Source 89
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