Phytic Acid in Soy Is Recalcitrant

Phytic Acid in Soy is Recalcitrant

Soy is high in a substance called phytic acid which binds to minerals in your digestive tract and keeps your body from absorbing those minerals. In many foods, the phytic acid content is reduced by soaking (in the case of beans, soaked porridge, and bread during rise time). But the phytic acid in soy is recalcitrant. You can soak and soak and still have phytic acid.

A 1985 study by Sutardi and Buckle tested the level of phytic acid in soy after differentstages of preparation. I provide many of those stages in the figure at Left. Keep in mind that the activities I list in the figure are successive: the researchers boil the beans, pour off the water, soak them again, dehull them, steam them, drain them, and cool them. The phytic acid levels change very little with all of this effort.
It is only when they ferment the beans in the form of tempeh that the phytate levels reduce to about 45% of the levels of the soaked soybean. Fried tempeh is an improvement still, but if the tempeh is stored for two weeks at 5ºC and then fried, the researchers reached the optimal (but not perfect) reduction of the phytic acid. A 2003 study also found that the phytic acid level decreased by only 31% by fermenting soybeans (Egounlety and Aworth 2003).
Keep these results in mind as you shop for soymilk and tofu. Soybeans in soymilk are soaked, strained, and cooked. Tofu has an additional step – a coagulant is added. Both of these products retain nearly 100% of the phytates according to the results of the research I present. Eat tempeh for a soy fix, but eat it sparingly if you do not prepare it yourself and do not know that traditional preparation methods were used.

When you look at your tub of tofu and see that one of those 12 ounce tubs has 100 milligrams or so of magnesium, keep in mind that you would only absorb about 10% of that magnesium. You would likely triple that absorption in a fermented soy product. If you rely on legumes for iron and zinc, keep in mind that these minerals are also bound by phytic acid. Purchase the Phytic Acid White Paper for much more information on the world of grains, legumes, nuts, and seeds. In the meantime, enjoy some miso soup in the cooler weather. From the book - Rebuild from Depression, by Amanda Rose

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- Soy reduces T4 to T3 conversion:Inhibits iodine uptake and can cause hypothyroid symptoms and goitre (in 50%).

Goitrogenic effect strongest in tofu, soybeans and milk.

Fermented soy products much safer for Hashimoto’s patients i.e. miso/tempeh

Graves’ Disease and Hot Nodules- Eat more goitrogens - foods with an antithyroid effect.

Hashimoto’s Thyroiditis – Hypothyroidism- Eat goitrogens in moderation, and avoid soy- Cooking brassica vegetables is thought to reduce goitrogenic effect…????- Counteract negative effect by supplementing with iodine

High levels of phytic acid in soy reduce assimilation of calcium, magnesium, copper, iron and zinc. Phytic acid in soy is not neutralized by ordinary preparation methods such as soaking, sprouting and long, slow cooking. High phytate diets have caused growth problems in children.

Trypsin inhibitors in soy interfere with protein digestion and may cause pancreatic disorders. In test animals soy containing trypsin inhibitors caused stunted growth.

Soy phytoestrogens disrupt endocrine function and have the potential to cause infertility and to promote breast cancer in adult women.

* 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 analogs in soy are not absorbed and actually increase the body's requirement for B12.

Soy foods increase the body's requirement for vitamin D.

Fragile proteins are denatured during high temperature processing to make soy protein isolate and textured vegetable protein.

Processing of soy protein results in the formation of toxic lysinoalanine and highly carcinogenic nitrosamines.

Free glutamic acid or MSG, a potent neurotoxin, is formed during soy food processing and additional amounts are added to many soy foods.

Soy foods contain high levels of aluminiumwhich is toxic to the nervous system and the kidneys and can affect the conversion of T4 to T3.