It was a baffling medical mystery. A 21-year-old woman showed up at her doctor's office after having suffered abdominal pains and severe diarrhea for eight months — and losing 25 pounds.
Another patient, a 46-year-old man, arrived at the hospital with similar complaints. He had lost nearly 50 pounds.
In both cases, which occurred in Germany, the symptoms could have pointed to a severe food intolerance, serious bowel problems or worse. But after a battery of medical tests and a complete medical history, doctors in Berlin finally unlocked the secret behind the massive weight loss in these patients.
Sugarless gum. And lots of it.
Specifically, an ingredient in sugar-free gum called sorbitol — used instead of sugar to make the gum sweet — turned out to be the key culprit in both cases. In a report published Thursday in the British Medical Journal, the German doctors said the female patient had chewed up to 16 sticks of sugarless gum per day, while the male patient consumed about 20 sticks daily.
But in addition to being used as a sweetener, the ingredient has other uses in the medical arena.
"Both our patients consumed large amounts of sorbitol, which belongs to the family of polyalcohol sugars, like mannitol and xylitol, some of which are regularly used as laxatives," the study authors write.
"We've known about the diarrhea effects of sorbitol for some time," said Dr. David Posner, chief of gastroenterology at Mercy Medical Center in Baltimore. "People, when they overuse it, will have trouble with diarrhea and will lose weight because they have a lot of diarrhea and lose a lot of nutrients."
"It's actually a pretty classical teaching pearl when it comes to gastroenterology," said Dr. Ramon E. Rivera, gastroenterologist at Ochsner Medical Center's digestive disease center in New Orleans, La.
He notes that the cases elegantly illustrate the need for a complete and thorough medical history.
"History will give you the diagnosis," he said. "So most of the information you need is in the history itself."
"No one would think about asking the patient, 'do you chew gum?' But in medicine you have to be a detective. History is everything."
That being said, Rivera adds that cases this extreme — in which malnutrition occurs — are relatively rare.
The very property that makes sorbitol friendly for waistlines is actually the same characteristic that makes large quantities of it such a problem.
"What happens is that it creates an osmotic gradient; as it goes through the gastrointestinal tract, it's like a sponge that pulls water out of the intestinal walls," Rivera said. "So imagine a sponge going down the gastrointestinal tract and absorbing fluid as it goes along."
All of this excess fluid in the bowel leads to diarrhea, as well as the host of unfortunate abdominal effects that come along with it.
Rivera adds that whether or not an individual experiences such symptoms depends largely on the sensitivity of his or her digestive tract. This sensitivity varies widely from person to person, he says. So while one person may not experience gastrointestinal symptoms from chewing a few dozen sticks of sugarless gum per day, others might experience problems with that amount.
Coincidentally, at least one gum company in the past has touted its product as a weight loss aid.