Then Ed Yong writes something very relevant when reading all science research reports:
PS: I’ve written two pieces today about the microbiome. In this one, Akkermansia protected mice from malnutrition caused by other microbes and a poor diet. In the other, Akkermansia was associated with inflammatory disease, in mice that ate a diet rich in food additives. In other rodent studies, it stops mice from getting fat, but is more common in cases of bowel cancer. All of this illustrates a point I’ve made before: any one microbe can have very different effects in different contexts and circumstances. There is no universally “good” bacterium, no universally “healthy” microbiome.
A fix for X can worsen Y, in engineering as well as biology. And in economics, too. It's a simple rule, borne out by everyday observation if you care to look, but it's hard to get people to credit it. They want a silver bullet; they've been promised silver bullets, and if the silver didn't work somebody must be hiding something.