Nutritional Antioxidants and Prostate Cancer Risk


BERKELEY, CA -- (MARKET WIRE) -- 03/06/06 -- UroToday.com - UroToday
announces that new data regarding micronutrient antioxidants reduces
prostate cancer risk. Christopher P. Evans, M.D. reports on the
following:


Vitamins E and C and beta-carotene are micronutrient antioxidants that
neutralize free-radicals, which potentially contribute to prostate
cancer (CaP) carcinogenesis by inducing oxidative damage to DNA and
cellular components.


It is unclear whether these micronutrient antioxidants confer any
protection from the risk of developing CaP. This is of particular
interest, as the general population is strongly interested in
nutritional supplements and the SELECT trial is evaluating vitamin E
and selenium for CaP chemoprevention.


Dr. Kirsh and associates from the National Cancer Institute, Bethesda,
MD, and other institutions across North America evaluated the
Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO)
database for an effect of micronutrient antioxidants and report their
findings in the February 2006 issue of the Journal of the National
Cancer Institute.


Participants in the PLCO trial completed a baseline 137 item food
frequency questionnaire, which included questions on 12 individual
supplements. Relative risks of developing CaP were correlated with
intake of micronutrient antioxidants by Cox proportional hazards
models.


In the 29,361 men in the trial, 1,338 cases of CaP were identified
over the 8 years of follow-up. In general, there was no clear CaP risk
reduction resulting from dietary or supplemental intake of vitamins E
and C or beta-carotene.


However, there were subsets of participants that suggested a
beneficial role for micronutrient antioxidants. In smokers, decreased
risks of advanced CaP were associated with increasing dose and
duration of supplemental vitamin E use. In these men the age adjusted
rate of advanced CaP was 492, 153 and 157 per 100,000 person-years in
men who took no supplemental vitamin E, > 400IU/day, and those who
took vitamin E for 10 years or more, respectively.


In men with low dietary beta-carotene intake, supplemental
beta-carotene at a level greater than or equal to 2,000ug/day
correlated with decrease CaP risk. Specifically, the age-adjusted
risks of CaP were 1,122 and 623 per 100,000 person-years in men who
took no supplemental beta-carotene and at least 2,000ug/day,
respectively.


These data suggest a role for specific micronutrient antioxidants in
select cohorts of men.


By Christopher P. Evans, M.D.


Reference:


J Natl Cancer Inst 2006; 98:245-54


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16478743&query_hl=3&itool=pubmed_docsum


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