The role of diet in prostate cancer is not fully understood. However, American Cancer Society (ACS) researchers have noted a higher incidence of this cancer among men who eat high amounts of red meat and high-fat dairy products. Levels of prostate-specific antigen (PSA), a widely used biological marker for prostate cancer, were found to increase significantly slower in men who ate a diet rich in vegetable protein and low in both animal protein and saturated fat, according to a Reuters Health report.
PSA and Prostate Cancer
Although some argue that PSA is not that reliable a predictor of prostate cancer, it remains a valuable tool that medical professionals can use with other diagnostic procedures to help spot prostate cancer in its early stages. Cancer cells produce elevated levels of PSA, so a reading above normal levels for your age would prompt further investigation. However, a single reading outside normal levels is not necessarily cause for alarm. In an article written for AHealthyMe.com, Kevin Boyd points out that half of all men with a PSA level of 4 ng/ml (nanograms per milliliter) have no cancer. At the other extreme, a study published in the May 2004 issue of the New England Journal of Medicine found that 15 percent of a group of 2,950 men with normal PSA levels were suffering from cancer.
While cautioning that "research does not support definite nutritional guidelines for preventing prostate cancer," MayoClinic.com offers suggestions for foods that are likely to keep PSA levels within the normal range. These include whole-grain foods, including whole-wheat bread and brown rice; all kinds of fresh fruits and vegetables; and foods that are high in omega-3 fatty acids.
In the Running
Other foods and beverages that show promise, according to MayoClinic.com, include soybeans, other legumes and green tea. The first two include phytoestrogens, plant-based nutrients that act much like the human estrogen hormone in the body. Although research continues on the impact of soybeans and legumes on prostate cancer, an encouraging sign may be the sharply lower incidence of prostate cancer in the Far East where soy-based products are widely consumed. The polyphenols in green tea are antioxidants, which are believed to lower the risk of cancer and other illnesses.
Diet Slows Cancer's Growth
Reuters Health reported in January 2009 on a study of diet's effects on a group of 36 prostate cancer patients. The study, conducted by Dr. James Carmody of the University of Massachusetts Medical School and first reported in the December 2008 issue of Urology, found that the PSA "doubling time" and overall quality of life was increased substantially by a diet low in saturated fat and animal protein and high in vegetable protein. According to the report, "PSA 'doubling time' is the time it takes for PSA levels to increase by 100 percent." The results showed that the test diet slowed the advance of prostate cancer sharply.
Foods to Avoid
Just as there are foods that appear to keep PSA levels within the normal range, there are others that have the opposite effect, according to MayoClinic.com. Risky dietary choices include salt, sweets, alcoholic beverages and foods high in saturated foods, including dairy products. MayoClinic.com also cautions that overeating and obesity may markedly increase the risk of prostate cancer.