This week’s leaf is well suited to World Pulses Day on 10th February, day was established by the United Nations in 2019to promote legumes (beans, lentil etc.) as a global food. These crops are special, as the plants form a special symbiotic relationship with soil bacteria called Rhizobium that fix nitrogen from the air, obviating the need for the growers to add synthetic nitrogen fertilizer (see Leaf 68, https://lnkd.in/dGY_y5ee). Easy to grow and easy to dry and store, some 170 million tonnes of legumes are grown globally every year.
Faba bean (or broad bean) from the Viciafaba plant is not a top legume crop, but yearly production is still several million tonnes, and it has been cultivated for over 8000 years. It has high nutritional value as food and animal fodder, rich in protein, dietary fibre, vitamins and essential minerals.
But the story is not all good. Faba beans contain an alkaloid glycoside called #Vicine(molecule centered in cover picture). Vicine itself is harmless, but bacteria in the gut remove the sugar (green coloured right half of molecule) to leave the alkaloidaglycone called #divicine(red half on left) that gets absorbed. Divicine is pernicious because it reduces oxygen to superoxide, and this goes on to produce nasty reactive oxygen species(#ROS, see Leaf 4, https://lnkd.in/dUC-dBBH). Plants(even beans) supply us with plenty of ROS-scavenging antioxidants, but divicineis not one of them! Antioxidants are particularly important in red blood cells, and they consume Glucose-6-phosphate (G6P) to generate reducing power that keeps the antioxidants active. However, some 5% of the world population are deficient in the enzyme required, and thus suffer from a condition called #G6PD or #favism. These people cannot eat faba beans because the ROS produced from divicine overwhelm their antioxidative defences causing severe haemolytic anaemia.
So celebrate World Pulses Day by eating legumes, but not faba beans if you have G6PD.
Further reading
⬮ Wikipedia (2024). World Pulses Day. https://en.wikipedia.org/w/index.php?title=World_Pulses_Day&oldid=1228645686
⬮Hiu GD (1989). WORLD PRODUCTION AND TRADE INGRAIN LEGUMES. Grain legume workshop 1989, World Trade, https://lnkd.in/db-yfdqk
⬮ Faba bean (Vicia faba) https://www.feedipedia.org/node/4926
⬮ Lee HY et al (2022). Glucose-6-PhosphateDehydrogenase Deficiency and Neonatal Hyperbilirubinemia: Insights on Pathophysiology, Diagnosis, and Gene Variants in Disease Heterogeneity. Frontiers inFrontiersin Pediatrics, 10. https://doi.org/10.3389/FPED.2022.875877
