in the southwestern united states and mexico and reconstructed some of their microbial genomes the microbes they found dr kostic said resembled those of people in nonindustrialized societiesthose microbes helped people digest a wide variety of fibrous foods in huge quantities huntergatherers eat more than 50 grams of fiber each day dr kostic said while the typical american eats about 10 to 15 grams of fiber a dayif i were to try to boost my fiber intake to say 30 grams i could not do it without painful gi symptoms dr kostic said referring to the gastrointestinal tract and he adds he knows that from experience i have tried he addedthat raised the question would people in industrialized societies gain some beneficial microbes simply by changing their diets to ones more like the traditional hadza dietthat might depend on whether small amounts of any of those microbes still exist in the colons of people todayimagecreditkayana szymczak for the new york timesdr sonnenburg his research partner and wife erica sonnenburg and their colleagues tested that idea with mice fed a lowfiber diet after four generations on this diet those microbes were lost for good giving the animals a high fiber diet did not bring them back dr sonnenburg said adding the lost microbes back with fecal transplants is unlikely to help the microbes are unlikely to find a niche where they could survive and multiply enough to make a differencedr sonnenburg and others are trying to find ways of giving potentially beneficial ancient microbes a fighting chance by for example incorporating beneficial genes from ancient microbes into bacteria that already have a niche in the gutcountry microbes and city microbesdespite the enthusiasm for rewilding there is no good evidence yet that adding microbes to the guts of people in industrialized societies will improve health correlations between nonindustrialized societies microbiomes and an apparent protection from diseases like diabetes do not mean that changing the microbiomes of people in industrialized societies will give them the same protectionkeolu fox an anthropologist and genomics researcher at the university of california san diego calls the idea that such microbes will offer protection just so stories after the tales by rudyard kipling it is easy to build a narrative based on correlations he saidresearchers have a challenge ahead connecting the microbes and these diseases dr gordon saida lot more needs to be done to figure out what these organisms actually do and whether they do the same things in different microbial contexts he saidfor katie pollard director of the gladstone institute of data science and biotechnology in san francisco finding cures for autoimmune diseases is not just an academic exercise she has two chronic inflammatory conditions ulcerative colitis and ankylosing spondylitis and her son has crohns diseasei would love for my son to get better and myself she saidand while she agrees that the microbiome plays a role in these illnesses she questions the strategyeven if a modern hadza person wanted to donate how could this be