Foods with high concentrations of lectins, such as beans, cereal grains, seeds, nuts, and potatoes, may be harmful if consumed in excess in uncooked or improperly-cooked form. Adverse effects may include nutritional deficiencies, and immune (allergic) reactions.
The toxicity of lectins has been identified by consumption of food with high lectin content, which may lead to diarrhea, nausea, bloating, and vomiting.
Many legume seeds have been proven to contain high lectin activity, termed hemagglutinating activity. Soybean is the most important grain legume crop in this category. Its seeds contain high activity of soybean lectins (soybean agglutinin or SBA).
SBA is able to disrupt small intestinal metabolism and damage small intestinal villi via the ability of lectins to bind with brush border surfaces in the distal part of small intestine.
Heat processing can reduce the toxicity of lectins, but low temperature or insufficient cooking may not completely eliminate their toxicity, as some plant lectins are resistant to heat.
