High levels of phytic acid in soy reduce assimilation of calcium, magnesium, copper, iron and zinc. Phytic acid in soy is not neutralized by ordinary preparation methods such as soaking, sprouting and long, slow cooking. High phytate diets have caused growth problems in children.
Trypsin inhibitors in soy interfere with protein digestion and may cause pancreatic disorders. In test animals soy containing trypsin inhibitors caused stunted growth.
Soy phytoestrogens disrupt endocrine function and have the potential to cause infertility and to promote breast cancer in adult women.
Soy phytoestrogens are potent antithyroid agents that cause hypothyroidism and may cause thyroid cancer. In infants, consumption of soy formula has been linked to autoimmune thyroid disease.
Vitamin B12 analogs in soy are not absorbed and actually increase the body’s requirement for B12.
Soy foods increase the body’s requirement for vitamin D.
Fragile proteins are denatured during high temperature processing to make soy protein isolate and textured vegetable protein.
Processing of soy protein results in the formation of toxic lysinoalanine and highly carcinogenic nitrosamines.
Free glutamic acid or MSG, a potent neurotoxin, is formed during soy food processing and additional amounts are added to many soy foods.
Soy foods contain high levels of aluminum which is toxic to the nervous system and the kidneys.
Reference: Soy Alert! www.westonaprice.org