However, many soyfoods are processed in ways that decrease their fiber content significantly. Tofu and soy milk, two of the more popular soyfoods, contain very little fiber. Soyfoods that utilize the whole bean such as tempeh, soy four and textured soy protein, are high in fiber. About 30 percent of the fiber in soyfoods is soluble fiber. One half cup of cooked soybeans provides 88 mg of calcium.
Processing affects the calcium content of soyfoods considerably.
Soy milk contains about 80 mg of calcium per one cup serving. Although soyfoods are high in both oxalates and phytate, two compounds that inhibit calcium absorption, the calcium from soyfoods is very well absorbed and has a fractional absorption rate equal to that of milk. However, both phytate and soy protein reduce iron absorption so that the iron in soyfoods is generally poorly absorbed. Vitamin C can increase the amount of iron absorbed from soyfoods considerably, although absorption rates are still low. Iron may be better absorbed from fermented soyfoods like tempeh and miso.