Potential of Faba Beans, Rich in Protein, has been Unlocked

Faba beans have been an excellent source of food protein since pre-historic times, but about 5% of people can't eat them. Now, an international team of researchers has identified the gene responsible for the production of vicine and convicine, which are harmful to these people.

An international team of researchers, led by the Universities of Helsinki and Copenhagen as well as Luke Natural Resources Institute Finland, has identified the gene responsible for the production of vicine and convicine, which are harmful to these people. In the work published in Nature Plants, the team reports that the VC1 gene plays a central role in the biosynthesis these compounds.

Faba beans—Pythagoras and his followers avoided them and Roman priests of Jupiter associated them with death. Today, we know that faba beans produce the anti-nutrients vicine and convicine, which cause a risk for favism—a condition arising from damage to red blood cells—for susceptible individuals. Anti-nutrients are plant compounds that reduce the body's ability to absorb essential nutrients.

Among legumes—the pod-producing family of plants to which pea, bean, chickpea and soybean also belong—faba beans have the second-highest yield globally. They also have the highest seed protein content of the starch-containing legumes and out-perform soybean in cool climates. Faba beans are consequently a prime protein source for facilitating a global switch to a plant-based diet, considered necessary for significant reductions in carbon emissions.

However, when people deficient in a specific enzyme eat a large portion of uncooked faba beans, the vicine and convicine can cause their red blood cells to burst. The resultant hemolytic anemia, known as favism, has inevitably limited the potential use of faba beans. Although there are a number of faba bean varieties with low levels of vicine and convicine, the gene responsible for this trait was previously unknown.

Alan Schulman, one of project leaders and running a joint Luke and University of Helsinki lab, says, "It seems that the ancient Greeks and Romans must have been aware of the occasional serious illness caused by faba beans. It took until today to unlock the secret of that risk."