IT IS A standard party invitation in most respects. There’s a street map of the neighborhood, the address and time of the party, and some friendly encouragement to bring the whole family. The decorative elements, though, are unusual: a cutaway illustration of the interior of the human colon, its parts neatly labeled. Above this, in a festive typeface, it says, “Gut Microflora Party!” The host is Alexander Khoruts, a gastroenterologist and associate professor of medicine at the University of Minnesota. Along with the usual complement of colonoscopies and dyspepsia consults, he performs transplants of colon bacteria—aka gut microflora.
Almost everyone gathered at the party this evening is involved with this work. There is Mike Sadowsky, coeditor of the textbook The Fecal Bacteria and Khoruts’s research partner. Leaning into the buffet is Matt Hamilton, a University of Minnesota postdoc student who prepares the matter for transplant. Matt is spooning Khoruts’s homemade Russian red beet salad onto a plate, enough of it that a nurse tells him he’s going to “look like a GI bleed” tomorrow.
The nurse admires a platter of chocolate-covered whole bananas, one of the thematically appropriate desserts created by Khoruts’s thirteen-year-old. James is very much his father’s son, intelligent and cultured, with a sly sense of humor. He plays classical music on the grand piano in the living room and would like to write novels one day. The nurse asks James what number the desserts* would be on the Bristol Stool Scale. He replies without hesitating—4 (“like a sausage or snake, smooth and soft”).
It’s tough to find an inappropriate mealtime conversation with this group—not because they’re crass or ill-mannered, but because they view the universe of the colon very differently than the rest of us do. The interactions between the human body and its gut microbiome—as our hundred trillion intestinal roomers are collectively known—is a hot research area of late. For decades, medical investigators have looked at the role of food and nutrients in disease treatment and prevention. That has begun to seem simplistic. Now the goal is to tease apart the interactions between the body, the food, and the bacteria that break down the food. One example is the cancer-fighter du jour: the polyphenol family, found in coffee, tea, fruits, and vegetables. Some of the most beneficial polyphenols aren’t absorbed in the small intestine; we depend on colonic bacteria to metabolize them. Depending on who’s living in your gut, you may or may not benefit from what you eat. Or be harmed. Charred red meat has long been called a carcinogen, but in fact it is only the raw material for making carcinogens. Without the gut bacteria that break it down, the raw goods are harmless. (This applies to drugs too; depending on the makeup of your gut flora, the efficacy of a drug may vary.) The science is new and extremely complex, but the bottom line is simple. Changing people’s bacteria is turning out to be a more effective strategy for treatment and prevention of disease than changing their diet.
As a member of a culture that demonizes bacteria in general and the germs of other people in specific, you may find it disturbing to imagine checking into a hospital to be implanted with bacteria from another person’s colon. For the patient I’ll shortly be meeting, a man invaded by Clostridium difficile, it’s a welcome event. Infection with chronic C. diff—to use the medical nickname—can be an incapacitating and sometimes fatal illness.
“When you’re fifty-five years old and you’re wearing diapers that you’re changing ten times a day,” Matt Hamilton says, “you’re numb to the ick factor.” He lifts some stuffed tomatoes to his plate. Matt has the forceful, unabashed appetite of the big, young male.
“For the patient, there is no ick factor,” Khoruts adds. “They’ve been icked out. It’s a chronic disease and they just want to be rid of it.”