my #1 reason is because of the high amounts phyto-estrogen in soy. oh, and the fact that most soy is genetically motified. they also can mimic testosterone and inhibit the absorption of minerals like iron and calcium, and cause you to need more vitD and b12... i've also read something about the thyroid and i know that if you are susceptible to aluminum toxicity, that you should avoid soy (learned that in the book he's not autistic, but...). but anyway, when i was poking around looking for more reasons (i was hoping to make a top ten list), i found an actually list of ten reasons why that was so well written, i decided to just link to his blog (which i see that he posted it from another link but that one wouldn't work for me...) and repost it rather than coming up with a list of my own.
i'm just going to reiterate his last line really quick, though: "I personally do not eat soy and will avoid it at all costs." which is almost exactly what i do. i try not to buy anything that has soy in it - i will consider it if it is processed in a plant with soy (because that is nearly impossible to avoid), but, i'd say that 95% of our house is soyfree. that 5% would be soy sauce (which i rarely use) and other sauces that have soy sauce in them.
so, here is the list i didn't make:
- Phytic Acid. Soy contains high levels of phytic acid. In soy this reduces the assimilation of calcium, magnesium, copper, iron and zinc. High phytate diets have caused growth problems in children. It is possible to neutralise phytic acid in soy through methods such as soaking, sprouting and long, slow cooking. However most soy in modern times is not prepared through these methods.
- Protein Digestion. Trypsin inhibitors in soy interfere with protein digestion and may cause pancreatic disorders. In test animals soy containing trypsin inhibitors caused stunted growth.
- Phytoestrogens. Soy phytoestrogens disrupt endocrine function and have the potential to cause infertility and to promote breast cancer in adult women.
- Hypothyroidism. To add to the point above, 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. Vitamin B12 analogs in soy are not absorbed and actually increase the body's requirement for B12.
- Vitamin D. Rather than satisfying the body's needs for vitamin D, soy foods increase the body's requirement for this vital vitamin.
- Denatured proteins. Fragile proteins are denatured during high temperature processing to make soy protein isolate and textured vegetable protein.
- Processing. Processing of soy protein results in the formation of toxic lysinoalanine and highly carcinogenic nitrosamines.
- MSG. When soy is processed with typical food processing methods, free glutamic acid or MSG is formed. MSG is a potent neuro-toxin. Often additional amounts of MSG are added to many soy foods.
- Heavy metal toxins. Soy foods contain high levels of aluminum which is toxic to the nervous system and the kidneys.
I personally do not eat soy and will avoid it at all costs.