Beta-Carotene Can Cut Risk of Prostate Cancer
WebMD News Archive
Nov. 22, 1999 (New York) -- Men with low levels of beta-carotene in their
blood can reduce their risk of prostate cancer by as much as 32% by taking
beta-carotene supplements every other day, report Boston researchers in the
Nov. 1 issue of the journal Cancer. Men with the lowest blood levels of
beta-carotene at the start of the study had the greatest reduction in risk.
Beta-carotene is converted into vitamin A by the body. In addition to its
supplement form, beta-carotene can also be found in many fruits and vegetables
such as carrots, squash, yams, peaches, apricots, spinach, collard or mustard
greens, and broccoli.
Support for beta-carotene as an anticancer agent has been uneven, with at
least two large studies showing an increase in lung cancer in people that
received beta-carotene supplements. However, another study from the Boston
researchers reporting the new data found no harm, but no significant benefit
either. Other studies, notably the Chinese Cancer Prevention Trial, found a
reduced incidence of stomach cancer and mortality in a poorly nourished
population given a combination of beta-carotene, vitamin E, and selenium.
The latest data from the Physicians' Health Study, reported by Nancy R.
Cook, ScD of Brigham and Women's Hospital and Harvard Medical School, support
the hypothesis that beta-carotene may protect against prostate cancer
occurrence in some men. In the study, almost 15,000 male physicians
participated in the study, which was a large study of male physicians that
began in 1982. The men received either beta-carotene or a placebo.
Over the 12 years of study, close to 1,500 men were diagnosed with cancer,
including 631 with prostate cancer. Blood samples from these men were compared
with those of over 2,000 men who did not take beta-carotene supplements. Men
with the lowest blood levels of beta-carotene at the start of the study who
took supplements had a 32% reduction in risk of prostate cancer. Beta-carotene
supplements did not affect the risk of prostate cancer in men who had higher
blood levels of beta-carotene at the beginning of the study.