When the Gut Runs Low on Fiber, Its Guests Eat the House

Researchers at the Ludwig Institute for Cancer Research in Princeton published a finding that reads like a fable told in biochemistry. When the microbes in the human gut run out of dietary fiber, some of them begin to eat us.

Not us, exactly. They eat the mucus lining, the slick layer that keeps the intestinal wall sealed off from the trillions of organisms pressed against it. Jenna AbuSalim, Joshua Rabinowitz and their team traced the chemistry. Fed on fiber and the indigestible plant proteins the team nicknamed Prif, the bacteria give off one set of compounds. Starved of it, they turn to host proteins, and the byproducts shift to phenols tied to worse outcomes in cancer and kidney disease.

The wall that protects us is maintained by feeding the very creatures who could take it apart.

There is no malice in this. The microbes are hungry, and hungry things eat what is nearest. Take away the meal they prefer and they do what any starving creature does. The barrier holds as long as the guests are fed.

The psalm sings the whole created order gathered at one table, every creature waiting for food in due season and gathering what the open hand provides. The psalmist was singing about God's provision. He knew nothing of the gut. But the picture turns out to be unexpectedly literal.

The next line, verse 29, names the other half: withdraw the provision and things come apart, return to dust.

Psalm 104:29You hide your face: they are troubled; you take away their breath: they die, and return to the dust.

We like to picture the body as a fortress with the world locked outside. It looks more like a household, and a household has to be kept fed. Our wholeness runs, in part, through the appetites of creatures too small to see.