Although your parents may have warned you that masturbation could cause you to go blind or grow hair on your palms, it turns out it might actually help protect against prostate cancer. A study of 29,000 men shows that regular ejaculations, including from sexual intercourse, masturbating, and nocturnal emissions or "wet dreams," can protect against cancer development, said lead researcher Michael Leitzmann of the National Cancer Institute. The study suggests that frequent ejaculations may decrease the concentration of "chemical carcinogens which readily accumulate in prostatic fluid" and may reduce the development of crystalloids "which have been associated with prostate cancer in some." The prostate is a small gland that produces some of the fluid for semen. Prostate cancer is the second most common kind of cancer--after skin cancer--diagnosed among U.S. men and is highly survivable if caught in time.
The new study, published in this week's Journal of the American Medical Association, was based on an ongoing survey covering a variety of health issues of thousands of men who were 40 to 75 when the study began in 1986. In 1992 they were asked to report the average number of ejaculations they had per month during ages 20 to 29, 40 to 49, and during the previous year. In later surveys they were asked to report if they had been diagnosed with prostate cancer. On average the men overall had four to seven ejaculations a month. No increased risk of prostate cancer was seen in men who reported more frequent ejaculations, and there appeared to be a decreased risk in men with the highest reported levels. The two highest activity levels--13 to 20 ejaculations a month, and at least 21 a month--were linked with decreased cancer risks of 14% and 33%, respectively.
The research supports data from an Australian study published in July 2003 that found that the more often men ejaculated between the ages of 20 and 50, the less likely they were to suffer from prostate cancer. Those who ejaculated at least once a day while in their 20s were one-third less likely to develop prostate cancer. "The more you flush the ducts out, the less there is to hang around and damage the cells that line them," Graham Giles, lead author of the earlier study, said at the time.
Prostate cancer risk factors include advancing age, a family history of the disease, a high-fat diet, and being African-American. Most cases of early prostate cancer cause no symptoms and are identified only by routine screenings. More advanced cases may have such symptoms as a slowing or weakening of the urine stream, the need to urinate frequently, blood in the urine, impotence, and pain in the pelvis, spine, hips, or ribs. The American Cancer Society and other groups recommend annual prostate cancer screening for all men beginning at age 50. Such screening involves a blood test for a prostate-specific antigen, a protein produced by the prostate, as well as a digital rectal exam, in which a physician palpates the gland. Men who have an increased risk for prostate cancer, such as African-Americans and men with a family history of the disease, are advised to get tested earlier, usually at age 45.