Re: Sorting Out Soy propaganda.

Sally Fallon and Mary G. Enig are propagandists pushing info. spin to its fullest ignorance.

Here is a rebuttal to the subject matter of phytates.

Sally Fallon and Mary G. Enig

Animal studies are at the very foundation of many of the accusations against soy. But animals are not the same as humans, so foods that affect them in one way may well affect us differently. Protease inhibitors are substances that retard the action of digestive enzymes that cause the breakdown of protein. Fallon and Enig refer to studies that show that protease inhibitors isolated from soybeans can cause cancer in some animal species, but there is almost no evidence even suggesting that they have the same effect in humans. In fact, protease inhibitors found in soybeans appear to reduce the incidence of colon, prostate and Breast Cancer in humans.

Fallon and Enig make much of a 1985 study which showed that soy increases the risk of pancreatic cancer in rats. But researchers with the National Cancer Institute point out that the pancreas of a few species of animals, notably rats and chicks, are extraordinarily sensitive to dietary protease inhibitors such as those found in soy. This sensitivity has not been found in other species such as hamsters, mice, dogs, pigs, and monkeys, they say, and is “not expected to occur in humans.” In fact, while rats fed nothing but soy run higher risks of pancreatic cancer, human populations consuming high levels of soy have decreased rates of pancreatic cancer.

Species, even those that seem quite closely related, often function quite differently at a molecular level. It is true, as Fallon and Enig point out, that baby rats fail to thrive on soy. But they also fail to thrive on human breast milk. This is because rats and humans have vastly different requirements. Human milk, for example, is 5% protein; rats’ milk is 45% protein. The difference in nutritional requirements and responses for different species can be enormous. Foods that are highly nutritious for one species are often inedible or even poisonous to other species.

Fallon and Enig, however, build their case against soy upon animal studies. Soybeans are high in isoflavones — phytoestrogens, or plant substances that behave like weak forms of the hormone estrogen. K. O. Kline, M.D., of the Department of Clinical Science at duPont Hospital for Children in Delaware comments in a 1998 article in Nutrition Reviews. “It is clear from the literature,” writes Kline, “that different species and different tissues are affected by (soy) isoflavones in markedly different ways.” Fallon and Enig, however, do not agree. They denounce Kline’s comments, fuming that “this is scientific double talk.” To my eyes, in contrast, Kline’s remark is the thoughtful humility of a scientist acknowledging the realities and limitations of animal research.

Remember thalidomide, the drug that caused horrendous birth defects in children born to mothers who took the drug during their pregnancies? Thalidomide had been widely tested on animals, where it appeared to be totally safe. Similarly, the combination of fenfluramine and dexfenfluramine, recently touted to be the answer to dieters’ prayers, was extensively tested on animals and found to be very safe. Unfortunately it caused heart value abnormalities in humans. When the Arthritis drug Opren was tested on monkeys, no problems were found, but it killed 61 people before it was withdrawn. Cylert was fine for animals, but when it was given to hyperactive children it caused liver failure.

Does Soy Inhibit Mineral Absorption?

Fallon and Enig are adamant in their beef with soy, however, and their indictment of the bean continues. They fault soy for its phytic acid content. “Soybeans are high in phytic acid,” they say, “a substance that can block the uptake of essential minerals — calcium, magnesium, copper, iron and especially zinc in the intestinal tract… Vegetarians who consume tofu as a substitute for meat and dairy products risk severe mineral deficiencies… Phytates found in soy products interfere with zinc absorption more completely than with other minerals. Zinc deficiency can cause a ‘spacey’ feeling that some vegetarians may mistake for the ‘high’ of spiritual enlightenment.”

It is true that soybeans are high in phytates, as are many plant foods such as other beans, grains, nuts and seeds, and it is true that phytates can block the uptake of essential minerals, and particularly zinc. This would be a problem if a person consumed large amounts of phytates; for example, if they ate nothing but soybeans or wheat bran. But the phytic acid levels found in a plant-based diet including a serving or two of soy a day are not high enough to cause mineral absorption problems for most people eating varied diets. Furthermore, when soy products are fermented — as they are in tempeh, miso, and many other soyfoods — phytate levels are reduced to about a third their initial level. Other methods of soy preparation such as soaking, roasting and sprouting also significantly reduce phytate content.

While phytates can compromise mineral absorption to some degree, there is absolutely no reliable evidence that vegetarians who eat soyfoods “risk severe mineral deficiencies.” The complete adequacy of vegetarian diets is now so thoroughly proven and documented that even the National Cattlemen’s Beef Association has acknowledged the legitimacy of meatless diets. In an official statement, these representatives of the beef industry declared, “Well planned vegetarian diets can meet dietary recommendations for essential nutrients.”

The statement that vegetarians risk severe mineral deficiencies sounds frightening, but Fallon and Enig provide no supporting documentation. The statement that “zinc deficiency can cause a ‘spacey’ feeling that some vegetarians may mistake for the ‘high’ of spiritual enlightenment” is totally unsupported by any data whatsoever, and is devoid of any scientific basis.

Let’s look, one by one, at the minerals Fallon and Enig claim to be lacking for vegetarians.

* Zinc: It is wise for vegetarians to include plenty of zinc-rich foods in their diets, but the levels of zinc found in the hair, saliva, and blood of vegetarians are typically in the normal range. Zinc deficiency would be particularly harmful in pregnant women, but studies of pregnant women have consistently found no difference in zinc status between vegetarians and nonvegetarians.

Iron: Vegetarian diets are much higher in vitamin C, and vitamin C greatly enhances iron absorption, so even without eating red meat (which is high in iron), and even with the reduction in iron absorption from phytates, vegetarians are no more prone to iron deficiency than are nonvegetarians.
Copper: Vegetarian diets tend to be higher in copper, which overrides any reduced rate of absorption from phytates. Vegans, in particular, consume considerably more copper than meat-eaters.
Magnesium: Although the higher phytate content of soybeans and grains slightly reduces magnesium absorption, vegetarians diets are typically so much higher in this crucial mineral that vegetarians consistently show markedly higher serum magnesium levels than do nonvegetarians.
Calcium: Calcium from soy is nearly as bioavailable as calcium from cow’s milk. Hundreds of studies have found vegetarians in the West to have healthier bones, more positive calcium balance and less osteoporosis than meat-eaters — as well as less heart disease, cancer, high blood pressure, obesity, and diabetes, and substantially longer lifespans.
Without providing any supporting evidence, Fallon and Enig go on to say that “soyfoods block calcium and cause vitamin D deficiencies… The reason that Westerners have such high rates of osteoporosis is because they have substituted soy oil for butter, which is a traditional source of vitamin D…needed for calcium absorption.” Actually, as Westerners have eaten less butter, they’ve replaced it with margarines which, like butter, are fortified with vitamin D.

Why, then, do Westerners have such high rates of osteoporosis? We have become sedentary, plus we consume a highly processed, high-salt, high-animal protein diet. Study after study has found that the more animal protein you eat, the more calcium you lose.

The calcium-losing effect of animal protein on the human body is not a matter of controversy in scientific circles. Researchers who conducted a recent survey of diet and hip fractures in 33 countries said they found “an absolutely phenomenal correlation” between the percentage of plant foods in people’s diets, and the strength of their bones. The more plant foods people eat (particularly fruits and vegetables), the stronger their bones, and the fewer fractures they experience. The more animal foods people eat, on the other hand, the weaker their bones and the more fractures they experience.

Similarly, in January 2001, the American Journal of Clinical Nutrition published a study that reported a dramatic correlation between the ratio of animal to vegetable protein in the diets of elderly women and their rate of bone loss. In this seven-year study funded by the National Institutes of Health, more than 1,000 women, ages 65 to 80, were grouped into three categories: those with a high ratio of animal to vegetable protein, a middle range, and a low range. The women in the high ratio category had three times the rate of bone loss as the women in the low group, and nearly four times the rate of hip fractures.

Might this have been due to other factors than the ratio of animal to vegetable protein? According to the study’s lead author, Deborah Sellmeyer, M.D., Director of the Bone Density Clinic at the University of California, San Francisco, Medical Center, researchers found this to be true even after adjusting for age, weight, estrogen use, tobacco use, exercise, calcium intake, and total protein intake. “We adjusted for all the things that could have had an impact on the relationship of high animal protein intake to bone loss and hip fractures,” Sellmeyer said. “But we found the relationship was still there.”

What, then, about Fallon and Enig’s assertion that Westerners have such high rates of osteoporosis because they have substituted soy oil for butter, and as a result no longer consume enough vitamin D for calcium absorption? Vitamin D is indeed needed for calcium absorption. But skin exposure to sunlight is the primary source of vitamin D in humans. In fact, people whose skin is not exposed to direct sunlight have difficulty getting enough vitamin D from their diets without supplementation. A 1999 report in the American Journal of Clinical Nutrition said that blood levels of vitamin D in sunlight-deficient people don’t begin to rise until 4,000 units of vitamin D are consumed. Someone relying on butter for this amount would have to eat four pounds of butter a day. The data simply provide no basis whatsoever for blaming the osteoporosis rates in Western culture on the decrease in butter consumption. They do, however, point a definite finger at animal protein consumption, which helps explain the reduced rates of osteoporosis in people consuming soyfoods. Tweet