Soy Isoflavones are natural compounds that are considered phytoestrogens, according to the Linus Pauling Institute at Oregon State University. Natural food sources of soy isoflavones are soy beans, legumes and certain vegetables. Research shows that soy isoflavones have both positive and negative effects on men. Soy Isoflavones in men reduce the risk of prostate cancer, decrease cognition and increase infertility.
Reduce Prostate Cancer Risk
Prostate cancer death rates are significantly higher in the United States compared to Japan and China, where dietary soy intakes are much higher. Researchers from the Linus Pauling Institute, or LPI, suggest that soy isoflavones have a potential role in prostate cancer risk. Individuals diagnosed with prostate cancer showed a significant decrease in cancer progression when administered soy isoflavones, according to the LPI. Men who where administered a high-phytoestrogen diet consisting of soy isoflavones showed a significant improvement over men who received a lower soy diet. Several LPI studies concluded that soy isoflavone consumption did not prevent prostate cancer, but was associated with a reduced risk of prostate cancer.
Soy isoflavones have been reported to improve cognitive performance in females, but in men it has had opposite effects, according to the LPI. Cognitive function refers to the processes of memory, thinking, learning and judgment. One observational study concluded that men who consumed soy at least twice a week had poorer cognitive test scores compared to men who consumed less soy. Another Indonesian study reported by the LPI also concluded an association between memory loss and soy isoflavone consumption in elderly men.
Soy isoflavones have long been suggested to play a vital role in different male reproductive disorders and male infertility. Research published from the Oxford Journal exmained the link between soy isoflavones and semen quality and found unfavorable results for men. The studies concluded that men who had the highest intake of soy isoflavones had a signficantly lower sperm count compared to men who did not consume soy. This decrease in sperm concentration is associated with male infertility and male reproductive disorders, according to the Oxford Journal.