Doess soya affect manhood?

20s to 40s: Privates in Peril
In a Harvard study published last year in the journal Human Reproduction, Jorge E. Chavarro, M.D., Sc.D., and his colleagues found a strong association between men’s consumption of soy foods and decreased sperm counts. Ninety-nine men reported their intake of 15 different soy-based foods, then underwent semen analysis. Those in the highest category of daily soy intake averaged 32 percent fewer sperm per milliliter of ejaculate than those who went sans soy.

Dr. Chavarro cautions that this doesn’t prove cause and effect, and that it’s too early to counsel men to avoid soy foods in the hope of boosting fertility. “But clearly, this story is just starting,” he says. “More studies need to be conducted.”

If shooting blanks is worrisome, how about being unable to shoot at all? Two other recently published papers reveal that at least one soy component clearly impairs erectile function in animals—and may do so in men as well.

The studies, published in the Journal of Andrology and Urology respectively, looked at the effect of daidzein on the sexual function of male rats. Moderate doses of the phyto-estrogen administered either in youth or adulthood significantly affected the quality of their erections. Among other changes, the daidzein-exposed males produced less testosterone, had softer erections, and experienced biochemical changes to their penile tissues that left these tissues less elastic and less capable of complete blood engorgement.

While acknowledging that rat results do not always directly translate to humans, the authors of the first study suggest that this time there’s reason to believe they will. They cite, among other things, a 10 percent higher incidence of erectile dysfunction in Chinese men known to consume high amounts of soy compared with Americans who avoid it. The authors of the Urology study sound a similar warning. They argue that it’s reasonable to believe that men who consume lots of daidzein could experience tissue changes similar to those seen in another mammal.

Yufeng Huang, M.D., a coauthor on both papers, says that the “moderate” dose used in the animal studies leads to approximately the same blood level of daidzein in men who eat soy every day, a common practice in Asia. He believes soy represents a novel and previously overlooked risk factor for ED.

“We are now recommending that soy be avoided by patients with erectile dysfunction,” Dr. Huang says. And because erectile dysfunction increases with age, he also suggests that men ages 40 and above limit their soy intake.

Source:
http://www.menshealth.com/nutrition/soys-negative-effects/page/4