* Pylorus is Greek for “gatekeeper.” That’s all. As you were.
* Purchased in bulk from RodentPro.com. Life is cheap at RodentPro, as cheap as sixteen cents for an extra small pinky (a one-day-old frozen feeder mouse). Mice are also available in fuzzy (ten to fifteen days old), white peach fuzzy (“Just the right size when a pinky is too small and a fuzzy is too large”), hopper, weanling, and adult. Feeder rats and guinea pigs are sized like T-shirts: XS, S, M, L, XL, and XXL. RodentPro gift certificates are available. Because nothing says “I love you” like $100 of dead rodents delivered to the doorstep.
13
Dead Man’s Bloat
AND OTHER DIVERTING TALES FROM THE HISTORY OF FLATULENCE RESEARCH
THE SAME QUALITY that has allowed Mylar to rival latex as the material of choice for party balloons has secured its place in modern-day flatus research. Mylar is airtight. Your helium-filled Mylar Get Well Soon balloon will continue to float long after you are discharged from the hospital. The Mylar balloon I inflated in 1995 as part of a flatulence study might still, had anyone kept it, contain gas I produced by eating two-thirds of a pound of chili in the Kligerman Regional Digestive Disease Center cafeteria.
Alan Kligerman is the Kligerman of the Kligerman center, and he is the Ak in AkPharma, the company that founded the center and created Beano.* The active ingredient in Beano is an enzyme that breaks down certain complex carbohydrates, called oligosaccharides, found in large quantities in beans and other legumes. You have this enzyme in your colon, courtesy of bacteria that live there. Because your small intestine can’t absorb these complex carbohydrates, they carry on into your colon, where bacteria and their enzymes break them down—and create a lot of hydrogen in the process. Translation: beans make people gassy. Adding Beano to chili while it’s still on the table preempts this. It’s like having a surrogate predigest your beans.
I had visited Kligerman’s lab for a magazine piece. I still have my notes and interview transcripts, and a teal Beano windbreaker* that Kligerman gave me, but the details are hazy. I recall eating my carefully weighed chili at a table with Kligerman and Betty Corson, the voice of the Beano Hotline. My notes attest that a man called Len was also there. My lunch mates were eating the chili too, though they weren’t part of the study. They were just people who like beans, or had come to like them, since AkPharma purchased them in volume and cans could usually be found in the cupboards of the employee kitchen.
“I’ll open up a can of black beans, and I’ll eat the whole can,” said Betty.
Len was nodding. “I’ll take a can of baked beans. Pour the liquid off. That’s what I’ll eat for lunch a lot of times. I hate to admit it, but I’m one of the 50 percent of Americans that’s not troubled by beans.”
When someone at AkPharma says, “Troubled by beans,” trouble doesn’t refer to the embarrassment caused by the sounds or smells of flatulence. (Hydrogen and methane are odorless, remember.) Trouble refers to the pain and discomfort caused by gas inflating your colon. When the colon balloons, it activates stretch receptors that send a message to your brain, which your brain forwards to you as pain. Like most pain, it’s an alarm, a warning system. Because stretching can be a prelude to bursting, your brain is highly motivated to let you know what’s happening down there.
The older you get, the slacker the muscles of your colon become and the more easily the organ balloons. As Len gaily remarked, “We get flabbier all over, inside and out.” Sixty percent of Beano customers, he said, are over fifty-five. People with coronary artery disease whose doctors steer them away from fats and red meat are often advised to incorporate beans into their diet as a replacement protein. “Some of these people,” said Kligerman, “would come back to their doctors, going, ‘I’ll take my chances on a second heart attack over all this gas.’” Cardiologists in the fat-fearing 1980s handed out Beano sample bottles like Halloween candy.
The other food group that troubles the middle-aged gut is dairy. About 75 percent of Asians, African Americans, and Native Americans are deficient in lactase, an enzyme secreted in the small intestine that breaks down lactose, a sugar found in milk products. In Caucasians the rate is around 25 percent. Most can digest milk sugars while they’re young, but they begin to lose the ability as they age. “Once you’re beyond suckling age,” Kligerman pointed out, “there’s no biological reason for you to absorb lactose.” Were it not for the persistent hand of the dairy lobby—Got Marketing?—the notion of grown-ups drinking milk by the glass might seem as odd here as it does in much of the rest of the world.
Milk products follow the same biological plot line as beans. An ornery carbohydrate makes it to the colon intact because the small intestine couldn’t break it down into something absorbable. Colon bacteria go to town on it, spewing clouds of hydrogen in the process. Gastroenterologists can easily diagnose malabsorption of lactose (or gluten, for that matter). In the Bay Area, where I live, people prefer to self-diagnose. And misdiagnose. “Dairy sugar often travels with dairy fat, and big fat loads are hard on the gut,” says gastroenterologist Mike Jones. “People who claim lactose intolerance tend to also voice a belief that they’re gluten-intolerant. Usually with no evidence of either.”
True lactose malabsorption is no picnic. This was the source of the prodigious flatus of the pseudonymous patient A. O. Sutalf,* documented in 1974 and reported in the august pages of the New England Journal of Medicine. Mr. Sutalf, his identity a closely guarded secret to this day, passed gas an average of thirty-four times a day. By comparison, the lactose-tolerating adult will toot on average no more than twenty-two times a day,† peaking twice: five hours after lunch and five hours after dinner. Len maintained that the 5 P.M. peak was at least in part man-made: “You’ve been holding it in at work, and as soon as you get in the car to drive home you let it out.”
Whereupon Kligerman frowned. Earlier, when Len tried to tell a story that began, “There was a guy on my floor freshman year . . . ,” Kligerman threw this particular bucket of cold water: “This is not a humorous subject.”
When Kligerman got up to take a phone call, I scooted my chair over to Betty Corson’s side. I wanted to know who’d been calling the Beano Hotline lately. She told me about a woman whose boyfriend kept pulling over to “check the air in the tires.” More typically, it is women, mostly of my mother’s generation, who don’t want anyone, ever, under any circumstances, to hear them. Like the gassy nun at the Holy Spirit–Corpus Christi Monastery, who had called earlier in the day. “She talked very quietly,” said Corson.
Why not just avoid legumes? Some people can’t, said Corson. I challenged her to provide a single instance of a human being forced to eat beans. She came back with “refried-bean tasters.” They exist and they have called the hotline. “Can you imagine?” She slapped the table. “Honest to God.” With Kligerman gone from the table, the conversation had loosened its tie a little.
I know one other example of beans eaten against one’s will. Inmates in solitary confinement in state prisons are sometimes fed a single, nutritiously complete but wholly unappetizing food called Nutraloaf. (Often these are convicts who’ve attacked someone with their silverware. Nutraloaf is an entire meal you can pick up and eat by hand.) Beans are invariably a main ingredient, as are bread crumbs, whole wheat flour, and cabbage: major gas generators all. Inmates in several states have sued on the grounds that Nutraloaf three times a day constitutes cruel and unusual punishment. In the article I read, taste was the issue, but an elderly convict could probably build a case out of gas pain.
When Kligerman returned, he was carrying what looked like a potato chip bag with a snorkel apparatus at one end. He explained that he needed to get a baseline reading before I ate my beans. He handed the device to me. “When you do your blows—”
It was unlike Kligerman to employ slang in reference to flatus. It quickly became clear that the snorkelly thing, like any snorkelly thing, went in the mouth, not the rectum. I was both relieved and disappointed: he was doing a b
reath hydrogen test. If you know the amount of hydrogen someone is exhaling orally, it’s a simple matter to extrapolate the amount they’re exhaling rectally. This is because a fixed percentage of the hydrogen produced in the colon is absorbed into the blood and, when it reaches the lungs, exhaled. The breath hydrogen test has given flatus researchers a simple, consistent measure of gas production that does not require the subject to fart into a balloon.
Up through the 1970s, however, that’s how it was done. A retired bean scientist told me the story of a flatus research project carried out by the extremely appropriately named Colin Leakey, at a food science facility in Chipping Campden, near Stratford-upon-Avon. If I’d been a tourist passing through, I might have skipped the Shakespeare and gone over to Chipping Campden to have a peek. “People walked around in gowns”—hospital, presumably, not ballroom—“with a tube coming down and around and up into a balloon.” Stateside, in 1941, J. M. Beazell and A. C. Ivy rigged up something similar: “The gas was collected in a thick-walled rubber balloon by means of a 22 French colon tube which was inserted into the rectum about 10 cm [4 inches]. In order to hold the tube in place, a broad strip of dental rubber dam was attached to it at the point where it emerged from the rectum and this was brought up snugly along the gluteal fold and fixed to the abdomen and back by means of adhesive tape. With this arrangement the subjects were able to remain ambulatory with surprisingly little discomfort.”
The researchers were fooling themselves, says Michael Levitt. “The rectal tube is . . . uncomfortable, tends to plug, and cannot be used for prolonged periods in free-living subjects,” he wrote in a 1996 paper. For studies of gas volume, he preferred the “flatographic recording” technique, wherein the subjects would make a notation in a special diary of each “passage.” The method isn’t entirely dependable, however, because different people’s passages may contain widely varying amounts of gas, depending on whether . . . how shall I put this? On whether they are my husband or my mother-in-law. On whether they expel it with gusto or try to hold it in, letting it out in many tiny squeakers and falsely upping their flatographic tally.
Len pointed out a related shortcoming to the breath hydrogen test. When people, stereotypically women, hold in their gas, they absorb more of it into their bloodstream, “so it comes out in the breath.” This artificially raises their breath hydrogen numbers and may serve to explain the occasional highly counterintuitive finding that women are more flatulent than men.
“Right, Alan?”
Kligerman stirred his chili. “I don’t know, Len. I don’t know what the ultimate fate of a suppressed fart is.”
RECTAL TUBES AND breath hydrogen bags have their drawbacks, but either is an improvement on the original methodology. One of the earliest flatus studies on record was carried out by the Parisian physician François Magendie. In 1816, Magendie published a paper entitled “Note on the Intestinal Gas of a Healthy Man.” The title is misleading, for although the man in question suffered no illness, he was dead and missing his head. “In Paris,” Magendie wrote in Annales de Chimie et de Physique, “the condemned ordinarily, one hour or two before their execution, have a light meal.” With red wine. So French! “Digestion is thus fully active at the moment of their death.” From 1814 to 1815, the city fathers of Paris, seeming also to have lost their heads, agreed to release the bodies of four guillotined men to Magendie’s lab for a study on the chemical makeup of flatus. One to four hours after the blade had dropped, Magendie extracted gas from four points along the digestive tract and measured what he could.
One of the prisoners Magendie “opened” had consumed lentils as part of his last meal. I would have expected this man to have had the highest hydrogen level—legumes, as we just learned, being the largest supplier of unabsorbed carbohydrates to hungry colon bacteria. Oddly, the highest hydrogen level came out of the prisoner who had eaten “pain de prison et du fromage de Gruyère.” Gruyère cheese and “prison bread.” Were Paris jailers serving some sort of early French precursor to Nutraloaf? Probably not. For many people, unabsorbed carbohydrates from wheat are a sizable contributor to gas. And if you’re going to be dead in two hours, there’s no reason not to fill up on bread.
What amazed me about Magendie, aside from his zest for gore, was this: using instruments available in 1814, he was able to detect hydrogen sulfide, a gas that typically makes up one-ten-thousandth of the gas produced in the human colon. It’s possible the instrument Magendie used was, in fact, his nose. The human olfactory system detects the rotten-egg smell of hydrogen sulfide at the practically nonexistent rate of .02 parts per million. Though present in no more than trace amounts, hydrogen sulfide is, in the words of Michael Levitt, “the most important determinant of flatus odor.” He would know.
* * *
* AkPharma has since sold the Beano brand to pharma giant GlaxoSmithKline. As part of a marketing campaign, GSK’s website included an online University of Gas. Hoping to matriculate—or at least buy a sweatshirt—I clicked on the video. The stately campus building in the background was instantly familiar to me as Baker Library at Dartmouth College, where my parents once worked. Given what I know of the Dartmouth frat scene, it was kind of apt, but I ratted GSK out anyway. The president’s office did not seem to share my outrage (“At this time, I don’t have a comment from President Kim about the Beano University of Gas”), but a cease-and-desist letter eventually went out, and the image was removed.
* But one example of the sly marketing genius of AkPharma. Beano was also the sponsor of a team of hot air balloonists in a prominent race.
* ?ti teG
† I brought Levitt a scrap of notebook paper covered with hash marks, the score card of an anonymous family member who kept track for two days, totaling thirty-five and thirty-nine. “Yeah,” Levitt said, “every time I give a talk someone comes up and tells me twenty-two is way too low.”
14
Smelling a Rat
DOES NOXIOUS FLATUS DO MORE THAN CLEAR A ROOM?
MICHAEL LEVITT DID not set out to make his mark on the world by parsing the secrets of noxious flatus. His fellowship advisor had the idea. The gas chromatograph had just come into use as a laboratory tool, and no one had yet had the ingenuity—or nerve—to apply the technology to human emissions. “He called me into his office,” Levitt recalls. “He said, ‘I think you ought to study gas.’ I said, ‘Why’s that?’ He said, ‘Because you’re pretty much of an incompetent, and this way if you discover anything, at least it’ll be new, and you’ll be able to publish something.’”
Levitt published thirty-four papers on flatus. He identified the three sulfur gases responsible for flatus odor. He showed that it is mainly trapped methane gas, not dietary fiber or fat, that makes the floater float. Most memorably, to this mind anyway, he invented the flatus-trapping Mylar “pantaloon.”
“Even now,” he says of his flatus work, “it overshadows everything else I do.” Levitt and I are sitting in a conference room upstairs from his lab at the Minneapolis VA Medical Center. Levitt has a goofy, lopsided smile and a pale complexion. I couldn’t recall, while writing this, whether his hair was gray, so I typed his identifiers into Google Images. A photograph of a can of baked beans came up.
For the record, here are some of Michael Levitt’s other contributions to medicine: He invented the breath hydrogen test, which originated not as a flatulence assessment technique but to diagnose malabsorption of carbohydrates in the small intestine. He debunked a diet fad for foods made with “nonabsorbable” carbohydrates. He showed that the wriggling movements of the villi are the key to intestinal stirring and to healthy absorption of nutrients. “I wrote the book on intestinal stirring.”
After what I judge to be a sufficient number of follow-up questions on intestinal stirring, I ask whether it might be possible to see the Mylar pantaloons.
Levitt designed the garment for a pair of studies that aimed both to identify the gases responsible for noxious flatus and to test devices claiming to adsorb—the for
mal term for binding to something’s surface—those gases. He doesn’t know where they are stored, but digs out a photograph of a woman standing in the lab, modeling them. Shown uninflated, they fit more snugly than I’d pictured them. The material is silver, crinkly, and reflective. They’re the sort of clothes baked potatoes wear.
I ask Levitt whether it was difficult to recruit volunteers for the flatus studies. It wasn’t, partly because the subjects were paid for their contributions. People who sell their flatus are more or less the same crowd who turn up to sell their blood.
“What was hard,” Levitt says, “was finding the judges.” Levitt needed a pair of odor judges to take “several sniffs” and rate the noxiousness—from “no odor” to “very offensive”—of each of the sixteen people’s flatal contributions.* The hypothesis was that noxiousness would correlate with the combined concentrations of the three sulfur gases. And it did.
Curious as to which olfactory notes the different sulfur gases contributed to the overall bouquet of flatus, Levitt purchased samples of the three gases from a chemical supply house. The judges agreed on the following descriptors: “rotten eggs” for hydrogen sulfide, the gas with the strongest correlation to stink; “decomposing vegetables” for methanethiol; and “sweet” for dimethyl sulfide. Though lesser players like methylmercaptan contribute as well, it is for the most part these three notes, in subtly shifting combinations and percentages, that create the infinite olfactory variety of human flatus. To quote Alan Kligerman, “A gas smell is as characteristic of a person as a fingerprint is.” But harder to dust for.