Hemagglutinin and Food Poisoning from Beans

Here's a fun fact: Eating soaked raw or undercooked beans can result in food poisoning. The culprit is a plant lectin known as phytohaemagglutinin or simply hemagglutinin, a chemical known to cause agglutination of mammalian red blood cells and to disrupt cellular metabolism. According to the US Food and Drug Administration, phytohaemagglutinin is found in many types of beans, but red kidney beans contain the highest levels of hemagglutinin. White kidney beans contain a third as much toxin while broad varieties of beans contain 10% as much hemagglutinin as red kidney beans. This is still plenty, since you only need to eat 4-5 undercooked red kidney beans to get sick.

Bean Poisoning Symptoms

Symptoms start to appear within 1 to 3 hours after consuming the beans and include nausea and vomiting followed by diarrhea and, in some cases, abdominal pain. Although the symptoms may be severe enough to warrant hospitalization, they resolve spontaneously within a few hours. Everyone is susceptible, regardless of age, gender or other factors.

Preventing Bean Poisoning

It is easy to prevent bean poisoning. The recommended procedure is to boil soaked raw beans in water for at least 10 minutes. It is important that the water reach boiling or 100°C, since exposing the compound to 80° C actually increases its toxicity about 5 times.

Share Your Experience

Had you ever heard of hemagglutinin in beans or bean poisoning? Have you ever experienced this type of food poisoning? Feel free to post a reply.