The prostate is a walnut-sized organ that sits below a man’s bladder. It produces the milky liquid that makes up most of semen. The urethra passes through the prostate on its way to the penis. As a man urinates the urine flows from the bladder, through the prostate then to the penis.
When the prostate enlarges it squeezes the urethra making urination difficult. Prostates normally enlarge with age; this is known as benign prostatic hyperplasia (BPH). With some men this enlargement becomes a slow-growing cancer that stays localized in the prostate. Often this type of cancer is just watched carefully and not treated. With other men the cancer turns into an aggressive form that spreads through the body.
NCI Study
The Journal of the American Medical Association reported a 2004 study in the USA by the National Cancer Institute that followed 30,000 middle-aged or elderly white men over a period of eight years and found that higher ejaculation frequency during the men’s early adulthood correlated with a significantly reduced risk of prostate cancer after middle-age. Men who had ejaculated 21 times per month were found to be 33% less likely to develop prostate cancer than those who had ejaculated four to seven times per month. This study confirmed a smaller but similar 2003 Australian study.
The two studies disproved an earlier theory that frequent ejaculations increased the risk of prostate cancer. The old theory was based on poorly designed studies that failed to take into account risky behaviors that contributed to sexually transmitted diseases which in turn contribute to cancer.
The reported benefit appeared when the ejaculation frequency exceeded 12 per month, or approximately ever other day, and increased to the maximum of 33% when the frequency reached 21 per month--or almost daily. The doctors warned that the benefit would be lost if men increased their frequency by risky behaviors. Safe sex is still important.
The benefit was also more associated with ejaculations before the age of forty. That is, the data suggested that it is more important for young men to ejaculate frequently than for older men. The researchers took into account other factors such as obesity and the amount of physical exercise. For instance, some men who exercise frequently also have sex more often. When these men fail to develop prostate cancer, the data must be adjusted so that the benefit from the exercise and the benefit from the ejaculations are determined separately.
The scientists involved stated that the benefit was clear with the slow-growing, organ-confined types of prostate cancer but less clear with the aggressive metastasizing forms.
It’s believed that the benefit comes from three factors associated with ejaculation; reducing stress, reducing toxins in the tissues of the prostate, and clearing microdeposits from the ducts in the prostate gland.
Besides ejaculation, other ways of avoiding prostate cancer are:
Leitzman et al, “Ejaculation Frequency and Subsequent Risk of Prostate Cancer,” Journal of the American Medical Association, vol 291, page 1578.