A Happy Pooper is a Healthy Pooper

Despite growing scientific evidence that imbibing any amount of alcohol is unhealthy, I’m betting that champagne corks were popping over at the Institute for Systems Biology in South Lake Union on October 6. That’s when news broke that the ISB’s Mary Brunkow would share in the 2025 Nobel Prize in Physiology or Medicine.

A molecular biologist, Brunkow is one of three scientists to be honored in Oslo for their discoveries concerning peripheral immune tolerance. She worked with one of the others, immunologist Fred Ramsdell, now at Sonoma Biotherapeutics in San Francisco, to identify the specific gene—out of 170 million of them—on which a mutation can have the effect of unleashing the immune system to rage out of control, attacking otherwise healthy organs willy-nilly. The Nobelists’ discoveries have led to development of potential treatments, now in clinical trials, for autoimmune diseases and cancer.

The biology and scientific sleuthing involved in all this are fascinating and explained well by the Nobel Assembly here. And you can make your day a little brighter by listening to the phone call Brunkow took at 4:30 a.m. on the day of the announcement from a representative of the Nobel Assembly—his second try to tell her the good news. She ignored the first call, thinking any call from Sweden must be junk. (Ramsdell got the news at a campground while vacationing in Montana.)

But because my interests tend to be more, uh, mundane, I couldn’t help but be distracted from talk of T-cells by an unrelated press release featured on the ISB’s news webpage: “Timing is Everything: ISB Study Finds Link Between Bowel Movement Frequency and Overall Health.” While it may not be Nobel-worthy, this is the sort of research I can get behind.

A team of ISB scientists analyzed data from subscribers to Arivale, a Seattle-based consumer wellness company co-founded by genomics pioneer Leroy Hood, who earlier founded the ISB. Hood envisioned Arivale as “the Google or Microsoft” of scientific wellness, but it turned out to be the Pets.com. Arivale launched in 2014 and shut down abruptly after just five years.

In that time, however, thousands of subscribers seeking customized wellness plans had shared extensive information about themselves—answering myriad questions about their health, diet, habits, and lifestyle. Also they submitted samples of their blood and—try to picture the procedure involved—stool.

ISB researchers focused on the data from 1,425 healthy Arivale subscribers, deriving a trove of insights into the intricacies of human elimination, results they detailed in the journal Cell Reports Medicine. Most importantly, they found that defecation has a big impact on your gut and so potentially on your overall health and maybe on your sense of wellbeing.

It turns out that as your pooping goes, so goes your gut microbiome. It’s a microscopic world filled with trillions of bacteria, viruses, fungi, and parasites—stuff you would go out of your way to avoid if you encountered it anywhere else. The ISB is engaged in research to better understand how gut microorganisms interact and cooperate, so as to improve the design of probiotics and others therapies.

ISB scientists found that healthy guts (not bigger, necessarily, but containing a more salutary set of microorganisms) are most common among people who poop 1-2 times a day. This rate is what the PhDs refer to in technical nomenclature as “the Goldilocks zone.” Which, just to be clear, has nothing to do with the temperature of your stool being neither too hot nor too cold. This is all about the frequency with which you produce it.

You probably don’t need to worry if your routine is close to but not in the zone. Anywhere between three bowel movements a week and three a day is considered normal. But below that range, you’re constipated, above it, you’re diarrheal, and either way, the data suggests maybe you should worry.

That’s because guts in the Goldilocks zone contain more fiber-fermenting bacteria associated with good health, while constipated and diarrheal bowels contain significantly more bacteria associated with protein fermentation, which can produce some nasty by-products. Constipated people (besides being no fun to be around) carry by-products in their blood that can damage their kidneys. People with diarrhea carry by-products that can damage their liver.

Remember, the people in this study were healthy overall. Physicians have long known that constipation, for example, is common among people with kidney disease, Alzheimer’s disease, and neurodegenerative disorders such as Parkinson’s disease, but this new study suggests constipation and diarrhea may be long-term causes of illness, not merely consequences.

Inevitably, the ISB found that people who say they eat lots of fiber, stay hydrated, and exercise regularly tend to live in the Goldilocks zone. But some surprises pop out of the data—for example, about gender differences: “In particular, females tended to eat more vegetables and fruits in a week and had a higher diarrhea frequency. Males, on the other hand, showed higher weekly snack intake and easier bowel movements.” Score one for the fellas, I guess. No word on trans toilet habits; clearly, more research is needed.

It seems that pooping is one of the few things that get easier as we age. Younger subjects were more likely to be diarrheal, yet older ones “were more likely to report having greater ease of bowel movement.” Could one factor here be time spent on the potty and whether Instagram is involved? These are questions the Arivale subscribers were not asked, so we can only wonder.

Most intriguing is the finding that constipation and diarrhea are both associated with a somewhat elevated risk of suffering from depression or anxiety and of having family members who do. Family influence is pervasive in our lives, of course. Further study of its role in defecation and associated neuroses could be productive, so to speak. In this as per usual, great writers are way ahead of the scientists. I’m thinking of a passage from Philip Roth’s 1972 novel Portnoy’s Complaint, with which I will leave you:

Jesus, this father! Whom I have had forever! Whom I used to find in the morning fast asleep on the toilet bowl, his pajamas around his knees and his chin hanging onto his chest. Up at quarter to six in the morning, so as to give himself a full uninterrupted hour on the can, in the fervent hope that if he is so kind and thoughtful as this to his bowels, they will relent, they will give in, they will say finally, “Okay, Jack, you win,” and make a present to the poor bastard of five or six measly lumps of shit. “Jesus Christ!” he groans, when I awaken him so as to wash up for school, and he realizes that it is nearly seven-thirty and down in the bowl over which he has been sleeping for an hour, there is, if he’s lucky, one brown angry little pellet such as you expect from the rectum of a rabbit maybe—but not from the rear-end of a man who now has to go out all clogged up to put in a twelve-hour day. “Seven-thirty? Why didn’t you say something!” Zoom, he’s dressed, and in his hat and coat, and with his big black collection book in one hand he bolts his stewed prunes and his bran flakes standing up, and fills a pocket with a handful of dried fruits that would bring on in an ordinary human being something resembling dysentery. “I ought to stick a hand grenade up my ass, if you want the truth,” he whispers privately to me, while my mother occupies the bathroom and my sister dresses for school in her “room,” the sun parlor—“I got enough All-Bran in me to launch a battleship. It’s backed up to my throat, for Christ’s sake.” Here, because he has got me snickering, and is amusing himself too in his own mordant way, he opens his mouth and points downward inside himself with a thumb. “Take a look. See where it starts to get dark? That ain’t just dark—that’s all those prunes rising up where my tonsils used to be. Thank God I had those things out, otherwise there wouldn’t be room.”