Let's continue discussing the attack on soy by our butter-and-lard-loving friends at the Weston Price Foundation.
They don't like the soy isoflavones. They think they're the equivalent of human estrogen. Actually, they are phyto-estrogens, and plants are full of them. All beans and legumes contain them. Wheat germ is a very potent source of phytoestrogen. And oil-seeds are extremely high in them. However, in oil-seeds, they are referred to as lignans. Flaxseeds are very high in lignans, and sesame seeds are even higher. Sesame seeds may be the highest phytoestrogen food on the planet. So, why are they beating up on soy when it's just one of many plant foods containing phytoestrogen? And what is the real scoop on isoflavones?
First, isoflavones are not estrogen. They are "estrogen-like" compounds, meaning that there is some molecular similarity. But, in biochemistry, it doesn't take much variation to alter the effects of something radically.
Dr. Mark McCarty PhD, an internationally recognized authority on isoflavones, says that soy isoflavones act on different receptors than human estrogen, which bypass the potentially harmful effects of estrogen. He says that soy isoflavones exert "a restraining influence" on cell proliferation in opposition to the stimulatory effect of regular estrogen. That is why soy isoflavones are considered anti-cancer.
The Life Extension Foundation reports that: "Dozens of epidemiological studies document the broad array of health benefits associated with a high-soy diet. Diets rich in soy isoflavones are associated with lower rates of cardiovascular disease, osteoporosis, cancer, and Type 2 diabetes."
But, will soy isoflavones turn boys into girls, as the Weston Price Foundation suggests? Well, let's take me as an example. I eat some soy. I'm still having my fruit and tofu smoothie in the mornings. I also eat beans regularly- at least 4 or 5 times a week- and they're all high in isoflavones. I rarely eat flax seeds, but I regularly eat sesame seeds, which again, are even higher in phytoestrogen. Then, the whole grains and nuts I eat daily also contribute phytoestrogens. So, with all that, what's my testosterone level? Total testosterone is given a normal range of 280 to 800 nanograms per decaliter. It's a big wide range because testosterone flucturates according to a man's age. Younger men tend to have a lot of it, and older men tend to have much less. So, theoretically, younger men would be closer to 800 and older men would be closer to 280. What's mine at age 60? My total testosterone is 803.
But what about the anti-thyroid effect of isoflavones? There is a kernel of truth to that. Isoflavones do reduce the body's utilization of iodine, and the same is true of isothionates, which occur in cruciferous vegetables, such as cabbage, broccoli, cauliflower, and brussel sprouts. These effects have been known and studied for a long time, and the American Board of Endocrinologists says that moderate consumption of both is safe. However, I realize that is hardly going to quell the controversy. But here is how I look at it: millions of Americans- perhaps tens of millions- are hypothyroid, and most of them are standard eaters. They haven't been loading up on soy or broccoli, yet they still became hypothyroid. The most common form of hypothyroidism is Hashimoto's thyroiditis, also called auto-immune thyroiditis, and it's not caused by soy or broccoli. Avoiding too many dietary goitrogens is one thing, but if you were going to try to avoid them completely, you would have to avoid cruciferous vegetables completely. But, that would surely be an over-reaction because cruciferous vegetables are extremely valuable foods. So are beans and legumes.
Besides, a much bigger problem than goitrogens in the diet is the amount of iodine in the diet. Iodine is a scarce nutrient. Plants don't need it, and they can grow perfectly well without it. The richest sources of iodine (if we forget about iodized salt) are seafood and seaweeds. Most Americans don't eat much fish, and they don't eat any seaweeds. In Japan, they eat a lot of fish and a lot of seaweed, and as a result, their average daily intake of iodine is 13 mg. In the US, the RDA for iodine is only 150 mcg. Do you know how much difference that is? 78 fold! Many complementary physicians believe that Americans are woefullly short on iodine, and they recommend iodine supplements, such as the Iodoral supplements developed by Dr. Guy Abraham, considered by many to be the world's leading authority on iodine. Anyway, rather than throw beans and broccoli completely out of your diet because of goitrogens, I think it would be better to take steps to insure you are getting enough iodine. That's what I do.
One thing is absolutely sure: the concensus in Medicine- including both conventional Medicine and complementary Medicine- is that both beans and cruciferous vegetables belong in a healthy diet. And I'll have more to say about that next time, in my last post on whether soy can kill.