Can food determine your genetics? The case of the fava bean.

Favism, also known as Baghdad fever, is a sickness and is also one of the most interesting and amazing examples of the interaction between food, genes and culture. This sickness affects many people in the Mediterranean region. Triggered by the consumption of fava beans (ful medames in Arabic) or coming into contact with the plant’s pollen, it results in dizziness, sleepiness, nausea, vomiting, discolored urine and possibly even death.

What’s more interesting is how this sickness coincides with annual malaria outbreaks in the region. In the 1950s an American physician named Paul Carson was examining the link between deaths of soldiers from some ethnic groups, mainly Italian and African Americans, from an apparent interaction with the anti-malarial drug primaquine. Using methods not allowed today by experimenting on prisoners, Carson identified a genetic “defect” linked to the deficiency in an enzyme called GSH which is essential for maintaining the integrity or red blood cells. These primaquine sensitive people had an anemic reaction when exposed to the drug. Carson was the first researcher to identify that people of different ethnic backgrounds could react differently to drugs or foods. Professor Arno Motulsky later identified the G6PD gene as responsible for this reaction.

Oddly enough sickle cell anemia and the similar reaction experience of GSH depletion of those genetically sensitive to fava beans or like affecting drugs cause cells to unload oxygen thus making the carrier of the disease/gene sick but also preventing harmful parasites like malaria from reproducing in cells and then potentially killing their carriers. Hence this genetic defect was actually a kind of genetic advantage.

As previously mentioned, favism is prevalent in certain populations; but here’s where the story starts to blow your mind. There was a debate if this was merely the result of natural selection, i.e. people with favism outliving those without it due to their enhanced immunity to malaria through random contact with favas, or what nutritional anthropologist Solomon Katz has called biocultural evolution, which would be in this case the intended human adaptation to disease through specific agricultural and culinary practices.

While this may sound far-fetched, there is a lot of evidence otherwise. Different cultures have reported the observation of this fact; that those with favism get sick from favas but don’t get malaria. This was also reflected in the ancient myths about the supernatural power of the fava by the Greeks, Romans and other Mediterranean peoples. Moreover they have practiced the intentional avoidance of green favas or the removal of shells of dried favas both of which are high in glycosides, the powerful pro-oxidants that deplete the GSH enzyme. Also, these Mediterranean peoples, despite religion or ethnicity, have had traditions of eating a lot of fava dishes in the spring coinciding with malaria season.

Perhaps most amazing is the fact that different Mediterranean and Middle Eastern recipes have employed different spice combinations for fava recipes traditionally served at different times of the year. Those that were traditionally served in malaria season tend to have the pro-oxidant spices like garlic, rosemary, onion, basil, cinnamon, cloves and rosebuds while fava recipes for other times of the year incorporate antioxidants such as lemon, sesame, oregano, thyme, paprika, sumac and chili peppers. Not only can different colors, smells and flavors be created and different emotions induced, but the favas can be treated to regulate the anemic-like side effects when not required or desired.

Humans have intentionally created genetic adaptation though culinary choices and favism is just one example. I hope you enjoyed wetting your tongue on the subject. This blog was based on one chapter of Gary Paul Nabhan’s excellent book entitled Food, Genes and Culture printed by Island Press. I highly recommend it if you’re interested in reading more on favism and other similar case studies and genetically appropriate diets, health and culture.

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