I love Scarlet runner beans. They both look beautiful and taste yummy. At times, I would over eagerly rush into my garden to see my newly formed “babies” and to savor their delicate flavor fresh off the vine. It came as a shock to me to discover that Scarlet and other runner beans should be thoroughly cooked before eaten due to the presence of lectin phytohemagglutinin, a chemical that causes red blood cells to clump together. This same hemagglutinin is responsible for giving the influenza virus its heartiness. Phytohemagglutinins also stimulates cell division and changes the cell membrane permeability to proteins.
Poisoning can occur by eating as few as FIVE raw beans. Symptoms show up about 3 hours after ingestion and include nausea, vomitting and diarrhea. Eight hours after ingestion, the symptoms should abate with no medical intervention necessary.
As is the case with many plant toxins, scientists have found a way to use phytohemagglutinin to their advantage in medicine. It is used to stimulate the production of T-cells and to track nerve signals in the brain.
Continue to grow and admire your Runner beans, but be sure to cook them thoroughly before eating them.
A copy of this article and other great gardening articles can be found at Her Gardening Blog.