These are proteins that interfere with digestion: inhibitors block the action of protein-digesting enzymes, and lectins bind to intestinal cells and prevent them from absorbing nutrients. Lectins can also enter the bloodstream and bind red blood cells to each other. They’re found mainly in soy, kidney, and lima beans. Both inhibitors and lectins are inactivated by prolonged boiling. But they can survive in beans that are eaten raw or undercooked, and cause symptoms similar to food poisoning.