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-1), 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-1 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.
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