Soybeans in fact contain a large number of dangerous substances. One among them is phytic acid, also called phytates. This organic acid is present in the bran or hulls of all seeds and legumes, but none have the high level of phytates that soybeans do. These acids block the body s uptake of essential minerals like calcium, magnesium, iron and especially zinc. Adding to the high-phytate problem, soybeans are very resistant to phytate reducing techniques, such as long, slow cooking.
Soybeans also contain potent enzyme inhibitors.
These inhibitors block uptake of trypsin and other enzymes that the body needs for protein digestion. Beyond these, soybeans also contain hemagglutinin, a clot promoting substance that causes red blood cells to clump together. These clustered blood cells are unable to properly absorb oxygen for distribution to the body's tissues, and cannot help in maintaining good cardiac health. Although the act of fermenting soybeans does deactivate both trypsin inhibitors and hemagglutinin, precipitation and cooking do not. Even though these enzyme inhibitors are reduced in levels within precipitated soy products like tofu, they are not altogether eliminated.