There is some conflicting evidence about the health benefits of eating soy products. On the one hand, there are studies showing that soy can help you reduce the risk of heart disease, cancer, osteoporosis, and diabetes. On the other hand, soybeans are high in phytic acid. Phytic acid has been linked to the malabsorption of calcium, magnesium, iron, and zinc in the body.
Now a new study concludes that soy may help prevent the development of early prostate cancer, but may increase the risk of advanced prostate cancer.
Reported in Cancer Epidemiology, Biomarkers & Prevention, the study focused on Japanese men. Dr. Norie Kurahashi and associates from the National Cancer Center in Tokyo wanted to investigate the association between dietary soy and the risk of prostate cancer.
Dr. Kurahashi was aware that historically Japanese men generally consume large amounts of soy products and also have a low rate of prostate cancer.
43,500 men were surveyed from 1995 through 2004. 307 were diagnosed with prostate cancer. The study concluded that the intake of isoflavones was linked with a decreased risk of early prostate cancer. And, the researchers noted, this protective effect was most pronounced among men over the age of 60.
However, Dr. Kurahashi’s study does not recommend soy products for those already diagnosed with prostate cancer. Apparently the intake of isoflavones was linked with an increased risk of advanced prostate cancer. Dr. Kurahashi concluded that further studies are needed “to clarify what period in life soy intake exerts an effect against prostate cancer and what type of prostate cancer it can prevent.”
So now we have more conflicting data concerning the benefits and risks of eating soy. What should you make of all this? All foods are made from a complex set of chemicals. They can be beneficial in many situations, but can be harmful when used inappropriately.
Scientists agree that soy contributes to heart health. The FDA has allowed food labels on soy products that state that a daily diet containing 25 grams of soy, also low in saturated fat and cholesterol may reduce the risk of heart disease.
And soy is a good source of protein. It contains enough essential amino acids to be considered equivalent to animal protein in quality. Perhaps the best way to look at soy intake and other “controversial foods” is to realize that soy by itself is not a magic food. Diverse foods from different food groups that together make a complete diet can have a positive effect on health.