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Prostate Cancer: Prevention and Survival
By Neal Barnard, M.D.
Just as women on high-fat Western diets have more estrogens circulating
in their blood and a higher risk of cancer of reproductive organs,
a similar process occurs in men. High-fat diets alter the amounts
of testosterone, estrogen, and other hormones in both men and women.
The prostate gland is just below the bladder in men, where it produces
semen to be mixed with sperm cells. Cancer of the prostate is the
most common form of cancer in American men, occurring primarily
in older individuals.
Cancer cells are found in the prostates of about 20 percent of
men over the age of 45 years.56 In most cases, these cancer cells
do not develop into cancerous tumors that affect the overall health
or life span of the individual. However, in many cases, the cancer
does grow, invade surrounding tissues, and spread to other parts
of the body. Although the disease varies greatly from one person
to the next, the average patient loses nine years from his normal
life span.57 One in ten men will develop prostate cancer at some
point in his life.
Just as countries differ markedly in the prevalence of breast cancer,
this hormone-related cancer also varies in exactly the same way.
Asian and Latin American countries have a much lower prevalence
of prostate cancer, while it is very common in Europe and America.
Ten men die of prostate cancer in Western Europe for every one who
dies in Asia.56
Cancer of the prostate is strongly linked to what men eat. Again,
animal products are consistently indicted: Milk, meat, eggs, cheese,
cream, butter, and fats are found, in one research study after another,
to be linked to prostate cancer.58-67 And it is not just dairy products
and meats. Some studies have also pointed a finger at vegetable
oils.25,59 Most recently, milk consumption has been linked to prostate
cancer due to high levels of the compound insulin-like growth factor
(IGF-I), both present in dairy products and in increased levels
in the bodies of those who consume dairy on a regular basis. A recent
study showed that men who had the highest levels of IGF-I had more
than four times the risk of prostate cancer compared with those
who had the lowest levels.68
Who has a lower risk? Countries with more rice,58
soybean products,65 or green or yellow vegetables69,70 in the diet
have far fewer prostate cancer deaths. It is not surprising that
vegetarians have low rates of prostate cancer.24,71 Becoming a vegetarian
in adulthood is helpful, but those who are raised as vegetarians
have the lowest risk.72
How does a Western diet cause cancer? Men who
consume diets based on animal products tend to have higher levels
of testosterone compared to men who eat plant-based diets. This
increase may be due to overproduction of these hormones in the body.
Also, fiber in the diet helps remove excess hormones with body wastes.
Those who eat meats and dairy products miss out on a substantial
amount of fiber, because animal products have no fiber at all. This
hormonal boost can affect the prostate, and is likely the reason
for increased cancer risk among those on meat-based diets.
Surviving Prostate Cancer
Diet may help improve survival in prostate cancer as well. When
pathologists conduct autopsies of men who die from accidents or
other causes, they find cancer cells in the prostates of about 20
percent of them.56 These men did not know they had cancer and had
no symptoms whatsoever. The prevalence of such "latent"
cancers actually varies with location, the lowest rates being in
Singapore (13 percent) and Hong Kong (15 percent), and the highest
in Sweden (31 percent).87 In most men, the cells never grow into
a large tumor, never spread, and never affect life or health in
any way. However, just as the prevalence of "latent" cancers
varies from one country to another, the likelihood that they will
turn into symptomatic cancer varies in precisely the same way, suggesting
that the same factors that cause cancer cells to form in the first
place also encourage them to grow and spread. So while a Swede is
twice as likely as a man from Hong Kong to have cancerous cells
in his prostate, he is more than eight times more likely to die
of prostate cancer.87
A low-fat, high-fiber diet can help eliminate the hormonal aberrations
that are known to be linked with prostate cancer, and may help improve
survival among those who have the disease. Unfortunately, there
has not been enough research in this area to know just how successful
dietary change might be.
Anthony J. Sattilaro, M.D., was president of Methodist Hospital
in Philadelphia when he was diagnosed with prostate cancer. He became
perhaps the most famous advocate for the use of diet against cancer.
In his best-selling book Recalled by Life, he told how
he adopted a low-fat, vegetarian diet and far outlived the grave
prognosis he had been given. The diet he followed is called "macrobiotic"
which is drawn from the best elements of a traditional Asian diet,
including generous amounts of rice and vegetables.
References
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