This was taken from: http://www.ehow.com/list_6373839_disadvantages-drinking-soy-milk_.html. We have always avoided soy - for some reason just never trusted it....no matter how slender Asians are. :)
This is just one article - please google soy milk on your own too - there is so much information out there!! We heard that it can really fry your thyroid - so we continue to avoid it.
For years the media has spread the good news about soy. Although many people have added soy into their diets to replace or supplement protein, instead of becoming healthier, they may have hurt themselves. Soy products are flooded with anti-nutrients and natural toxins that block enzyme use and affect digestive health. In addition to these, soy milk affects estrogen levels and blood clotting, brain and thyroid function, and has been linked to several diseases and cancers.
Estrogen and Blood
Unfortunately, soy has large quantities of estrogen. Men or boys who ingest soy products experience a suppression of testosterone. Although soy is said to reduce menopausal symptoms, no studies have gathered conclusive evidence to support this claim, according to the U.S. Department of Health & Human Services. In addition, soy milk has been linked to infertility, and giving an infant soy formula is equivalent to giving him five birth control pills per day. In addition, soy has been linked to breast cancer in women. Finally, hemagglutinin causes blood clots by promoting red blood cells to group and stick together, inhibiting oxygen and causing heart and vascular problems, according to ForeverLookinGood.com.
According to Mercola.com, the nutrient-blocking characteristics of soy products, caused by phytic acid, block zinc, calcium, magnesium, copper, and iron from being absorbed into the body. Zinc is linked to brain function and cognitive development and functioning. When zinc is not absorbed properly, it affects the immune system and causes mental decline and brain shrinkage. Zinc also controls the blood sugar regulation, protein synthesis, and collagen formation in the body, and is required for a healthy reproductive system. Soy milk also causes calcium to be leached from the bones. Soy products do promote the absorption of aluminum, however.
Disease and Cancer
Digestive health is severely affected by soy milk, according to Foreverlookingood.com. The trypsin inhibitors in soy products have been found to cause enlargement of the pancreas, and have been linked to pancreatic cancer. Isoflavones, found in soy products, act similarly to hormones and disrupt the endocrine system, causing thyroid conditions by suppressing thyroid function, according to Thyroid-Info.com. Isoflavones have even been linked to thyroid disease and cancer. Children were especially affected by isoflavones.
Government and Children
In 1913, the USDA referred to soy as an industrial product and not a food product. Soy has the largest percentage of pesticide contamination of any food. Children who were subjected to regular additions of soy milk into their diets would frequently vomit and have diarrhea after finishing a meal, according to Mercola.com. They acquired upper respiratory infections, rashes, and fever. In fact, children were unable to remove the nitrogen from their systems. U.S. government scientists even submitted documentation stating that the isoflavones in soy products are toxic.
Doesn't all that soy sound YUMMY!?