Ejaculation Frequency and Prostate Cancer: Is There a Relationship?
Several large studies have demonstrated a link between high ejaculation frequency and reduced rates of prostate cancer. On study done at Harvard followed over 29,000 men between the ages of 46 and 81, who reported their average number of ejaculations per month, including nocturnal emissions, masturbation, and sexual intercourse. The study found that men who ejaculated 21 times monthly or more had a 33% lower risk of prostate cancer compared to men reporting four-seven ejaculations per month. A study in Australia showed similar results, with men who averaged 4.6 to seven ejaculations weekly found to be 36% less likely to be diagnosed with prostate cancer before the age of 70. So what is the relationship between ejaculation frequency and prostate cancer?
The reduction in risk associated with frequent ejaculation should not be considered proof that ejaculation prevents prostate cancer. Other factors affect risk for cancer, including genetics, diet and lifestyle. The Harvard Study collected general health and lifestyle data for the study subjects and even in light of health and lifestyle variations among subjects, the reduction in risk held up well.
The reason for this reduction of risk is not well understood, scientists theorize that ejaculation empties the prostate gland of potentially harmful substances and irritants that could, over time, result in cellular damage and mutations that lead to cancer. Other theories suggest that ejaculation relieves stress. High levels of stress affect the immune system, a factor in onset of cancer.
Leitzmann MF, Platz EA, Stampfer MJ, et al. Ejaculation Frequency and Subsequent Risk of Prostate Cancer. Journal of the American Medical Association 2004;291:1578–86. PMID: 15069045.