The science magazine Nature has just published a pair of articles showing how gut bacteria evolve in response to diet differences by taking up new genes from distant relatives. The articles feature the recent discoveries by Jan-Hendrik Hehemann and colleagues that normal gut bacteria can gain the abilty to digest brown seaweed gums if they are fed sushi wrapped in dried brown seaweed for a long time, presumably over centuries of time. This all happens in the digestive canals of Japanese who have been supping on sushi for centuries.
The genes that give the gut bacteria gum digestion capabilities come originally from marine bacteria. No-one knows exactly when they moved, but it could have first been a thousand years or more ago, and it could have happened several times since then. The gum-dissolving genes are now also present in the non-marine bacterial flora living in Japanese people’s guts. The germ mating mechanisms that might make this happen are well understood by microbiologists — gut bacteria are well known to be able to mobilise and accept genes from different bacterial genera and even from creatures other than bacteria.
None of this is surprising to microbiologists but it is new to food historians, and adds something special to the venerable and tasty history of sushi.
The novel gum dissolving genes cannot yet be detected in Western guts. But if sushi continues to be popular in America and Europe, sooner of later they will.
Genetic pot luck
Justin L. Sonnenburg
Without the trillions of microbes that inhabit our gut, we can’t fully benefit from the components of our diet. But cultural differences in diet may, in part, dictate what food our gut microbiota can digest
Nature Vol 464|8 April 2010, page 837
Transfer of carbohydrate-active enzymes from marine bacteria to Japanese gut microbiota
Jan-Hendrik Hehemann, Gae¨lle Correc, Tristan Barbeyron, William Helbert, Mirjam Czjzek
& Gurvan Michel
Nature Vol 464|8 April 2010| doi:10.1038/nature08937, page 908
