This is a continuing series in response to the Weston Price Foundation attack on soy. This time we'll look at the anti-nutrients in soy, including protease inhibitors, trypsin inhibitors, and hemagglutinins.

Protease inhibitors are substances that inhibit or neutralize protein-digesting enzymes. The claim is that the protease inhibitors in soy cause the pancreas to work too hard, enlarge, and even become cancerous.

First, note that protease inhibitors are common in plants. lists the following foods as being rich in protease inhibitors: chickpeas, broccoli, lentils, brussel sprouts, potatoes, spinach, oats, corn, cucumber, pineapple, rice, soybeans, whole grain wheat, barley, almonds, and in that order. So, chickpeas are the highest. And keep in mind that they regard protease inhibitors as a good thing because they are considered anti-cancer. But, this proves that the attack on soy is really an attack on plant foods in general.

Protease inhibitors are destroyed by cooking. A North Dakota State University study found that 20 minutes of cooking at 100 degrees Celsius destroyed 87% of protease inhibitors in soy. Other studies have demonstrated up to 95% destruction of protease inhibitors from cooking.

Trypsin inhibitors are the best known protease inhibitors. Standard cooking methods destroy almost all of the trypsin inhibitors in foods. However, Dr. Messina of Loma Linda University reports that research using miniature swine showed that loading them up with even very high amounts of trypsin inhibitors caused no demonstrable harm.

But, the first sign of harm from trypsin inhibitors would have to be failure of protein utilization. What would that look like? Well, obviously, much protein goes into muscle, so there would be muscle atrophy and weakness. Protein is involved in immunity because the immunoglobulins which fight disease are proteins. So, you would have increased susceptibility to infections. And, protein is very much involved in digestion since digestive enzymes are proteins. So, you would have weak, faulty, symptomatic digestion.

Well, I'm not a big soy eater, but I do eat some, and as I look at myself, clearly, I am not being harmed. At 60, I'm as strong as I was in my 30s. When it's time to move heavy furniture, I can handle my end of the load, don't worry. When it comes to immunity, I practically never get sick. I can't tell you when I last had the flu because it's been too many years. And as for my digestion, I get a little bit of gas, but considerng how much fresh produce, whole grains, and beans I eat, it's not an inordinate amount, and overall, my stomach is a happy camper. My protein utilization seems to be just fine, so why should I worry about trypsin inhibitors?

Hemagluttinins are compounds in plants, particularly beans and legumes, that cause red blood cells to clump together. Some beans and legumes contain enough hemagluttinins to kill- if they are eaten raw. But soy is far from being the highest in hemagluttinins. Raw black beans contain far more hemagluttinins than raw soy beans, and red kidney beans contain the most of all common beans. Here in Austin, Texas where I live, black beans are king. They are served as a side dish in all the restaurants- it's part of the Tex-Mex culture. But if you go a few hundred miles east to New Orleans, it's red beans that rule. Red beans and rice are very popular, and not just in New Orleans but all across the South. And it doesn't stop there. Throughout the Carribean, red beans and rice are popular. When I went to Dominican Republic, I learned that red beans and rice are the national dish in that country. And I was impressed with the Dominicans; they're nicely proportioned, trim and slim compared to Americans. The little red bean used to make red beans and rice is actually a small red kidney bean.

So how big a problem are hemagluttinins in beans? Virtually none at all, if they are cooked properly. It certainly doesn't cause me any worry.. I buy the organic red kidney beans in cans. The USDA lists the small red kidney bean as the highest antioxidant food on the planet, followed by the wild blueberry, followed by the large red kidney bean. But, I'll have more to say about the extraordinary nutritional properties of beans in a later post. Next time, we'll look at soy and the thyroid. Stay tuned.