ergo-log.com

Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "

22.08.2009

Soya milk reduces chance of prostate cancer

Men who drink one glass a day of soya milk have a thirty percent lower risk of developing prostate cancer. Men who drink more than one glass a day of soya milk are more than seventy percent less likely to get prostate cancer. Epidemiologists at Loma Linda University in California discovered this in 1999 in a study of twelve thousand male Seventh Day Adventists.

Because Seventh Day Adventists have such a healthy lifestyle they make an interesting subject for epidemiologists. In 1976 and 1977 the researchers questioned twelve thousand men on what they ate. They then monitored the largest group of the men for a period of six years until the early 1980s. This was how the researchers discovered that drinking soya milk considerably reduces the chance of prostate cancer, as the table below shows.

Two thousand men were monitored for even longer. They were also involved in a study on the health effects of environmental pollution, the Men In The Smog study. This group was studied until 1992. The table below shows that the protective effect of soya milk was even greater than in the first study.

Men who drink two glasses of soya milk a day - equivalent to 400 grams - get 7 milligrams of daidzein and 10 milligrams of genistein. Daidzein en genistein are isoflavones. Isoflavones [structure below] have an anti-oestrogenic effect. They also inhibit the conversion of testosterone into the more aggressive DHT and have a direct inhibitory effect on cancer cells. The researchers believe that it's the isoflavones that cause this effect. Another possibility is that protease inhibitors in soya are responsible for the protective effect of soya milk.

The findings were not the first of their kind. Ten years earlier, in 1989, cancer researchers in Hawaii stumbled on the fact that soya products had a protective effect. [Cancer Res. 1989 Apr 1;49(7):1857-60.] The results of that study showed that men of Japanese origin had 65 percent less chance of developing prostate cancer if they ate tofu five times a week than men who only ate it once a week or less.

Source:
Cancer Causes Control. 1998 Dec;9(6):553-7.