The following article is used with the written permission of the author, Gillian Willis, pharmacist and toxicologist.

Uncooked Beans Toxicity

Certain UNCOOKED dried beans contain what are referred to as "proteolytic enzyme inhibitors." These enzyme inhibitors may prevent or decrease the utilization in the body of substances such as trypsin and chymotrypsin to produce nutritional deficiences.

Beans that can interefere with proteolytic enzymes are lima, kidney and soybeans. Cooking of the beans destroys these enzyme inhibitors. Other dried beans do not appear to contain these enzyme inhibitors, or if present, are in low concentrations.

The fava bean (Vicia faba) can cause a condition known as "favism" in susceptible individuals. In humans, this can occur from ingeston of the beans or inhalation of the pollen. Clinical manifestations include gastrointestinal upset, hemolytic anemia, bloody urine, jaundice and shock. This appears to be a hypersensitivity reaction.