I think that this study, reported at Newser, comparing the effect on the microbiome of eating artisanally produced sourdough bread with eating mass-produced white bread:
The study looked at the gut microbiomes plus clinical measures including cholesterol, blood sugar, fat, and mineral levels in 20 participants prior to its start. The subjects were then randomly assigned to either eat the sourdough or the white bread for one week, then take a two-week break and switch breads. Participants’ gut microbiomes did not appear to be changed based on the bread they ate and researchers found no measurable differences when looking at most markers, but they did find that while half the group had a higher blood glucose response to the white bread, the other half had a higher response to the sourdough. Based on subjects’ microbiomes, researchers could actually predict which half a participant would fall under. “The ‘one-size-fits-all’ diets that are given to the population as a whole, without personalization, are probably not optimal for everyone,” a co-author says, per CBS.
is likely to have some problems. How long does it take to see measurable changes in the composition of gut microbes? Your gut is a living ecosystem. It probably has its own mechanisms to reduce the rate of change. If you knocked out the gut bacteria of the participants at the beginning of the study it would be one thing but that doesn’t seem to be the case.
