NOT(Both/And)

A report on kwashiorkor has early suggestions that it might be caused not just by poor diet but poor diet plus an unfortunate gut bacteria mix. Another reports on how mouse gut bacteria can go nuts when the diet includes lots of emulsifiers. Very interesting articles. Go read them.

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.