Side Effects of Soy
- Effects on Digestion

Phytate present in the digestive tract binds minerals such as calcium, copper, iron, magnesium and especially zinc. Because of the important role of these minerals in so many bodily functions, the side effects of soy consumption could include negative effects on wound healing, protein synthesis, reproductive health, nerve function, and brain development.

The binding of iron could especially pose a problem for pre-menopausal women, who regularly lose iron. There may be a connection to the fact that women more commonly have low energy problems. Children require adequate iron for normal growth and development. However, it may be a benefit to non-vegetarian men who have an excess of iron in their diets. Iron is a free radical and reducing any over supply may be beneficial in reducing free-radical damage.

Some believe that one of the side effects of soy and other legume consumption in large quantities in developing countries has contributed to the generally shorter stature of people relative to those in developed countries; the connection being zinc deficiencies. A diet high in phytate may also negatively impact mental development.

In most phytate-containing foods, simply soaking for a day or two is enough to eliminate most of the phytate. However, soybeans require a fermentation process to reduce their phytate content to make them suitable for consumption. Soy, in the form of fermented products such as miso and tempeh, is much safer because fermentation has reduced the levels of phytate to very low levels.

Non-fermented soy products such as whole soybeans, soy milk, soy chips, soy protein isolates, soy flour have much higher levels of phytate and could, over time, pose a health risk.

Side Effects of Soy - Phytates Inhibit Enzymes
When food is eaten, digestive enzymes such as amylase, lipase, protease and others are secreted into the digestive tract to help reduce foods to a size and form where they can be absorbed into the body. The high content of phytates, which are enzyme inhibitors, in unfermented soybeans and soy products interferes with this process and makes carbohydrates and proteins from soybeans (and other foods present at the same time) less digestible. When foods are not adequately digested because of the presence of enzyme inhibitors, the action of bacteria in the large intestine may cause discomfort, bloating, and embarrassing gas. People such as the elderly who may already have low digestive enzyme production would suffer the worst effects from soy foods and their inhibition of what little enzyme activity they have to begin with.

When you think of it, this role of phytates in seeds is very necessary and put there for good reason. When you have grains and legumes stored in your kitchen pantry you don't want them to just start sprouting on the shelf. They are meant for long-term storage. But they are also meant for replanting to produce the next crop. All it takes is a time of exposure to water to remove the enzyme inhibitors (except in the case of soy beans) and the enzymes in the seed can go to work and begin the germination process (or, we can then eat them safely and enjoy the greater nutrition available from sprouted seeds.)