Researchers reported in 2016 that men who ejaculated more frequently were less likely to have prostate cancer—but the researchers didn’t know why. They now believe they have an explanation.
They call it the “prostate stagnation hypothesis.” In short, carcinogenic secretions accumulate in the prostate, which may create more opportunity for prostate cancer to develop. But ejaculation sweeps out these carcinogens. So, the more frequently that ejaculations occur, the fewer carcinogens will remain to cause cancer.
Both the 2016 study and the current study involved the same 31,925 male participants from the Health Professionals Follow-up Study (HPFS). The participants self-reported their average monthly ejaculation frequency in 1992 and researchers followed them for 18 years—up to 2010.
“The scientists found that men who ejaculated 21 or more times a month enjoyed a 33% lower risk of prostate cancer compared with men who reported 4 to 7 ejaculations a month,” wrote Marc Garnick, MD, on the Harvard Health Blog. Dr. Garnick is editor-in-chief of Harvard Medical School’s Annual Report on Prostate Diseases.
Because the researchers found that frequent ejaculation had a role in the prevention of prostate cancer—a disease with few known modifiable risk factors—the findings have meaningful public health implications.
“More frequent ejaculation in the absence of risky sexual behaviors could represent an important means of reducing the profound medical costs and physical and psychological side effects of unnecessary diagnosis and treatment of low-risk tumors,” the authors concluded in their 2016 study.
It’s in the genes
At that time, the researchers could only speculate why frequent ejaculation prevented prostate cancer. But, in a recently published study, they were able to identify biological processes that appear to link ejaculation frequency with prostate cancer.
For this investigation, the researchers explored whether gene expression patterns in prostate tissue varied according to the frequency of ejaculation. Specifically, they analyzed the expression of more than 20,254 genes in 157 men from the HPFS cohort who had developed prostate cancer. The researchers analyzed both prostate tumor tissue and adjacent normal tissue in the men.
Interestingly, they found no associations between ejaculation frequency and gene expression in tumor tissue. But in adjacent normal tissue, they found 409 genes and 6 pathways significantly associated with ejaculation frequency.
“These results suggest that ejaculation affects the expression of genes in the normal prostate tissue. The identified genes and pathways provide potential biological links between [ejaculation frequency] and prostate tumorigenesis,” the authors wrote.
In other words, this finding supports the prostate stagnation hypothesis.
“Regardless of the reason why, take comfort in the fact that ejaculation is not only pleasurable, but also may convey health benefits,” Dr. Garnick concluded.