Ah soy, the miracle food of the health conscious. Whether you intend to or not, you probably eat more soy then you think. It is second only to corn in terms of how much of it is grown each year in the U.S. Soybean oil is in just about any food that comes in a box, a bag or a can it seems, and if not the oil, soy lecithin really is in just about every thing in the supermarket. In fact, I challenge anyone reading this this to find a packaged/processed food that does not contain soy lecithin.
So, soy in some form, seems to be in just about anything we eat these days. The question of the day is whether or not this a positive thing for our health.
In a word, no.
You may find that answer surprising. You’ve probably heard that foods like tofu and soy milk are great alternative protein sources to animals foods, which have been vilified for their saturated fat content. If you have heart disease, you may have been told by your doctor to consume more soy products in order to lower your cholesterol. Or perhaps you have been told that soy foods will ease menopausal symptoms. If you are a committed vegetarian or vegan, soy foods probably form a large part of your diet. But here are a few of the main problems with increasing your consumption of soy:
1. Phytic Acid. This a chemical that can be found in pretty much all grains and legumes. Phytic acid helps prevent these seeds from germinating before they have found a suitable habitat in which to do so. This is accomplished by binding up minerals that enzymes in the seed need to begin the growth process. The problem is that phytic acid does a similar thing in your gut- binding with minerals and preventing their use and absorption by your body. This is the main reason why any and all grain products and legumes should be soaked for a period of time before their use and consumption. Soy, a legume, has one of the highest phytic acid contents of any plant food. We think of soy as being largely consumed by Asian cultures, but it did not become a dietary staple until it was discovered that by fermenting soy, the phytic acid content could be drastically reduced. The forms of soy traditionally consumed in the East are fermented soy products like tofu, natto, miso and traditionally brewed soy sauce or shoyu, NOT things like soy milk or soy-based meat imitations.
2.) Goitrogens. Goitrogens are chemicals that can suppress thyroid function. The thyroid is a gland in the front of your neck that regulates your metabolism. Goitrogens can be found in several families of plants, including brassicas like kale, broccoli, and cabbage, but are also found at very high levels in soy. This has been well documented since at least the 1930s but has been effectively suppressed by the soy industry lobby.
3.) Phytoestrogens, aka isoflavones. These are found at very high levels in soy also. In fact, you have probably been told that these are good for you and that they will lower your cholesterol and ease your hot flashes. But the fact is that they are exotic estrogen compounds- they are close enough to our own forms of estrogen that they can attach themselves at the same places our estrogen does, but they are different enough that the end result can be very different. For women going through menopause, the phytoestrogens can help ease symptoms by acting like the body’s own estrogen, which is declining during this period. In general however, these phytoestrogens may actually wreak havoc in the body by causing hormonal imbalance. For instance, certain types of breast cancer are estrogen sensitive. Excess estrogen can stimulate the growth of the cancer cells. Or consider this: the average age when girls hit puberty is 2 years earlier then it was 20 years ago. This has been blamed on growth hormones in milk, but I personally believe the increased use of soy products in the food supply is a more likely culprit because it means that girls are being exposed to more estrogen. And for my male readers who may be thinking, “I’m a guy, I don’t have estrogen, so this doesn’t effect me,” first of all, know that you do have some estrogen in your body, not as much as females of course. Secondly, Chinese monks use to consume large amounts of soy (tofu) not only because it was a vegetarian protein, but also because it decreased their libido and enabled them to better adhere to their vow of celibacy. So men, unless you are trying to be celibate and/or not have children, dosing yourself with phytoestrogens by eating increased amounts of soy may not be the best idea.
So, the verdict: Soy may be good for a lot of things, but food is not one of them!
The Whole Soy Story by Kaayla Daniel, Ph.D.