Monday, September 26, 2016

Common vetch and phocomelia

Phocomelia is "a rare congenital deformity in which the hands or feet are attached close to the trunk, the limbs being grossly underdeveloped or absent. This condition was a side effect of the drug thalidomide taken during early pregnancy," per the Oxford Dictionaries ( Thalidomide was used in the 1950's and 1960's to alleviate pregnancy nausea, but its horrible effects on babies led to its being abandoned.

Thalidomide is in use again as a cancer drug. It is now known that its main mechanism of action is to interfere with angiogenesis, the creation of new blood vessels from existing blood vessels ( Endogenous hydrogen sulfide (H2S) is an important part of angiogenesis, and inhibiting H2S-synthesizing enzymes negatively affects angiogenic processes (

Beta-cyanoalanine is a known inhibitor of two H2S-synthesizing enzymes, and it is found in common vetch (vicia sativa), a forage crop that is only suitable for consumption by animals with multiple stomachs ( However, dried split common vetch seeds resemble light red lentils and sometimes find their way into the human diet. Australia had a scandal back at the end of the 20th century where common vetch was being coated in vegetable oil to darken it and passed off as "orange lentils" to consumers (; some people were also sneaking common vetch from Australia into the food supply of countries such as Bangladesh and India.

An epidemiologic survey of phocomelia incidence ( found that the highest prevalence (out of areas that recorded it) was in southern Australia during the time period 1983-2000 ( Other areas with similar reported phocomelia rates were in Italy, Slovakia, and eastern Germany (, all areas where common vetch is grown (

India consumes a large amount of both red lentils (i.e., masoor dal) and common vetch, the latter which is supposed to be used only for animal feed, but due to financial issues, carelessness, and greed, it would be easy for common vetch to end up in the bowl of an impoverished pregnant woman. India suffers under a shortage of adequate medical personnel and resources, but doctors there are still identifying cases of non-thalidomide phocomelia. Two such cases were reported out of northern India in a February 2016 article:

This evidence I have found and summarized above points to the possibility that common vetch is an overlooked angiogenesis disruptor that is behind some cases of unexplained phocomelia. I hope that someone with more resources than I can carry this investigation further.

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