They live on opposite sides of the planet, but people in Malawi and Venezuela have similar microbes in their guts. Americans, on the other hand, have a distinctive microbiome with about 25 percent less diversity than indigenous Venezuelans’.
It comes down largely to diet, researchers determined after comparing more than 500 people from rural Malawi, the United States and the Guahibo society in Venezuela. Malawian and Guahibo diets are rich in corn and cassava, with meat an occasional treat. Gut microbes of the three groups reflected that, the team reported in 2012. Overall, Malawian and Guahibo gut microbiomes resembled those of herbivorous mammals, while American guts were more similar to carnivores’.
A more recent study found that major diet shifts can change the mix of gut microbes noticeably in just a day. Omnivores switching to a diet of all animal products saw the biggest change, as some bacteria boomed and others declined. Microbes settled back to their previous profiles a day or two after subjects returned to their usual diets, researchers report December 11 in Nature.