Favism is an acute hemolytic reaction triggered by exposure either to fava beans (Vicia faba) or to certain drugs (e.g., sulfa-based antibiotics and the antimalarial primaquine) in people with an inherited deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD). In favism, the patient can suffer from destruction of red blood cells, severe anemia, and possibly death. There are two necessary conditions for the disease: (1) genetic inheritance of the “Mediterranean” variant of the abnormal gene trait for G6PD deficiency; and (2) ingestion of fava beans, usually fresh, or exposure to some drugs. The bean is a dietary staple in areas where favism is reported. Only an estimated 20 percent of those with the genetic trait for G6PD are likely to experience episodes of favism. Under modern medical conditions the hemolytic anemia caused by favism is only rarely fatal. Strong evidence suggests that both the gene for G6PD deficiency and the cultural practice of fava bean consumption are evolutionarily adaptive traits that protect against death from all types of malaria. Favism, then, could be described as a negative outcome of the interaction of the positive adaptive qualities of both the gene and the bean.

Distribution and Incidence

Favism is found primarily in the Mediterranean and Middle East regions where fava beans are a staple food and the Mediterranean variant of G6PD deficiency gene is relatively common. Mark Belsey (1973) reports that it is frequently encountered in Greece, Sardinia, Italy, Cyprus, Egypt, Lebanon, Israel, Iran, Iraq, Algeria, and Bulgaria, and is particularly common among Sephardic Jews.