Masturbating more than five times a week between the ages of 20 and 50 could protect men against prostate cancer, Australian researchers claim today.
They think ejaculation could flush cancer-causing chemicals out of the prostate, a walnut-sized sex gland that lies at the neck of the urethra and the bladder. Another possibility is that it induces the prostate cells to mature fully, making them less susceptible to carcinogens.
Professor Graham Giles from the Cancer Council of Victoria in Melbourne discovered the apparent link, reported today in New Scientist magazine, after questioning 1,079 men who had prostate cancer about their sexual habits. He then compared them with 1,259 men of the same age. He found that men who had ejaculated more than five times a week in their 20s were a third less likely to develop aggressive prostate cancer later in life.
Prostate cancer kills 10,000 men in Britain annually, most of them diagnosed after reaching 70. There is no known cause, but it has a very slow onset, typically after men reach 50.
The results of the new study contradict previous studies, which suggested that having many partners or frequent sex increases the risk of prostate cancer by up to 40 per cent.
Professor Giles recorded the overall number of ejaculations, whether or not intercourse was involved, and suggested that infections caused by intercourse might help promote prostate cancer.
"The more you flush the ducts out, the less there is to hang around and damage the cells that line them,"said Professor Giles.
There is an intriguing parallel with breast cancer. Recent studies indicate that lactating reduces a woman's risk of breast cancer, possibly by flushing out the milk ducts.
Dr Chris Niley of the UK's Prostate Cancer Charity said: "It's plausible - which isn't the same as being true. One of the unanswered questions is whether the young men who were questioned may have exaggerated how many ejaculations they had had.
"It's also possible that the men who had cancer were looking around for a cause, and under-reported this side of their activity."Reuse content