When you turn over a tub of tofu or a carton of soy milk and marvel at the amount of magnesium in that bean curd, beware that precious little of it will make it into your brain cells. Likewise, little of the native calcium, zinc, or iron will nourish your body.
Soy is high in phytic acid which binds to these minerals and keeps you from digesting them. An article on the Rebuild site (and the video below) describes an interesting experiment on soy milk and phytic acid (pictured at right) which shows clearly the need to ferment soybeans in order to reduce their phytic acid content. In the graph, notice that researchers used a series of techniques to reduce the content of phytic acid in the soybean. These techniques were progressive as well — they performed the first soaking step and then the second (boiling) and third step (steaming) on the same batch of experimental beans. It took fermenting the soybean in the form of tempeh to see any appreciable reduction in phytic acid. Very little phytic acid was reduced simply by soaking and cooking the bean (which tends to be much more effective with other types of beans).
For other beans, read more about soaking beans at the Rebuild blog.
For an extensive collection of information on phytic acid (including recipes), buy the Phytic Acid White Paper.
Soaking grains @ the Rebuild blog
Oats and phytic acid @ the Rebuild blog
Soy and phytic acid @ the Rebuild blog
More posts like this one: