Perhaps the most well-known milk substitute is soy milk. I love soy milk. It is delicious. But I have a condition known as hypothyroidism which means my thyroid is an under acheiver. This makes me even more susceptible to the dangers of soy than the average guy. I had heard this once many years ago and when I asked my physician about it, he mumbled, (I had a mumbling doctor back then), that it didn't matter as long as I didn't drink it at or near the time I took my synthetic thyroid medicine.
Just like I believed the doctor who told me, (and in all fairness, he told me what he believed), that drinking radioactive iodine to manage my formerly over-active thyroid, I believed this one. He did, after all, tell me something I wanted to hear because I really, really liked the taste of my Vanilla Silk.
So here we are, years later, I'm having continual thyroid adjustment issues, and I start learning some food truths, some of which are about soy products. (Great. I already nixed the Diet Coke and now I discover the truth about my next favorite beverage...)
The phytoestrogens and isoflavones in soy inhibit and depress thyroid function. Not just a little, a lot. Hypothyroidism makes one more susceptible to heart disease, cancer and infections. Even without these possibilities, thyroid issues are no picnic. There's fun fatigue, dandy depression, gimpy gut and constantly cold appendages, just to name a few from the top of my head.
Infants fed soy milk receive estrogen concentrations at 13,000 to 22,000 times the amount of infants drinking breast milk or milk-based formula. Current research is studying the possibility of soy milk's compounds inhibiting the male infant's reproductive system, brain and other organs that are programmed for male characteristics during infancy's first six months. At this stage, male babies normally have a flood of testosterone-almost as much as that of a mature man.
Enzyme inhibition is also a great problem with soy and can lead to such goodies as cancer, a gamut of intestinal problems and in infants and children, growth retardation. It also causes a reduction in the amount of protein that can be digested and messes with assimilation of amino acids. Unfortunately, soy beans are full of some of the strongest enzyme inhibitors.
Another con: Phytic acid. This blocks absorption of essential minerals, zinc in particular. Zinc is needed for mental and reproductive development, for protein assimilation, collagen formation and the prevention of blood sugar imbalances. And without zinc, vitamin E, a powerful antioxidant, cannot be properly maintained in the bloodstream.
To add to the list of woes, in the heating process used to create commercial soy milk, carcinogens form.
In my book, this is plenty and enough said to warrant anyone a double check into soy products and in particular soy milk and soy infant formula.
(However, I feel it's important to add that where soy beans are concerned, there is a way to render them safe. According to Sally Fallon and Mary Enig, PhD, authors of Nourishing Traditions, the only way to make soybeans safe for consumption is through fermentation. Ordinary cooking, even with presoaking and slow cooking, is not enough for soybeans. But fermented soy products such as miso and tempeh are safe.)