Ganoderma
Antioxidant supplementation not associated with decreased risk of prostate cancer
Antioxidant supplementation not associated with decreased risk
of prostate cancer
February 15, 2006
Intakes of dietary or supplemental antioxidants were not
associated with a decreased risk of prostate cancer among men in
the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening
Trial, according to a study in the February 15 issue of the Journal
of the National Cancer Institute .
The study did find that
vitamin E and beta-carotene
supplementation may be associated with reduced prostate cancer risk
in certain population subgroups.
Research suggests that micronutrients such as
vitamin E,
vitamin C, and carotenoids may play
a role in preventing cancer development because of their ability to
combat
free radicals, agents that can
damage cellular DNA, lipid membranes, and proteins. In many
studies, vitamin E has been associated
with a reduced risk of prostate cancer, and beta-carotene has
been associated with increased lung cancer risk in previous
studies. However, no studies have examined associations between
intakes of these three antioxidant micronutrients and the risk
of prostate cancer.
Richard B. Hayes, Ph.D., at the National Cancer Institute, and
colleagues assessed the risk of prostate cancer for 29,361 men ages
55 to 74 enrolled in the PLCO Cancer Screening Trial, based on
their daily intake of beta-carotene, vitamin E, and vitamin C.
The
researchers looked at intake of antioxidants from both dietary
sources and from
supplements.
The authors found that, overall, dietary or supplemental intake
of vitamin E, vitamin C, or beta-carotene was not associated with
prostate cancer incidence in this group of PLCO trial participants.
However, certain micronutrients were associated with prostate
cancer risk in specific subgroups of men. For current or recent
smokers, high-dose, long-duration vitamin E supplementation was
associated with a reduced risk of advanced prostate cancer.
For men
with a low dietary intake of beta-carotene, high-dose supplements
of beta-carotene were associated with a reduced risk of prostate
cancer.
"Our cohort findings, although based on relatively short
follow-up, do not provide strong support for population-wide
implementation of high-dose antioxidant supplementation for the
prevention of prostate cancer," the authors write. "They do
suggest, however, that in certain population subgroups there was an
association between supplement intake and reduced risks of prostate
cancer."
In an accompanying editorial, I-Min Lee, Sc.
D., of Brigham and
Women's Hospital in Boston, Mass., and colleagues discuss the
implications of Hayes and colleagues' study in the context of
earlier studies of vitamin E supplementation and cancer risk. The
editorialists agree that the study results do not provide strong
support for the implementation of antioxidant supplementation for
the prevention of prostate cancer.
They note that the data remain
unclear about the benefits of vitamin E supplementation for
prostate cancer prevention in the general population; however,
there are strong data supporting smoking cessation to reduce cancer
incidence. The authors write, "Now and in the future, regardless of
the eventual findings on vitamin E supplementation and prostate
cancer risk, an important course of action for overall cancer
prevention is to continue efforts to prevent the initiation of
smoking and to promote the cessation of smoking among those who do
smoke."
Journal of the National Cancer Institute
.