Fat, Fructose May Worsen Gastric Upset
By Charlene Laino
WebMD Medical News
Reviewed By Brunilda Nazario, MD
on Monday, October 13, 2003
Oct. 13, 2003 (Baltimore) — Can avoiding certain foods help to relieve the bloating, tummy aches and general misery associated with irritable bowel syndrome?
That’s the intriguing possibility raised by two new studies that show that fat and fructose, the simple sugar found in honey, fruits, and some soft drinks, may contribute to symptoms of the misunderstood gastrointestinal syndrome that affects more than 1 in 10 Americans.
The research was presented here this week at the 68th Annual Scientific Meeting of the American College of Gastroenterology.
Young K. Choi, MD, of the University of Iowa in Iowa City, studied people with irritable bowel syndrome, or IBS, whose bodies cannot absorb fructose properly.
Irritable bowel syndrome is one of the most common gastrointestinal disorders, affecting almost 58 million Americans. People who suffer from it have symptoms of abdominal discomfort or pain, and they can alternate between diarrhea and constipation.
In this study, those who were able to eliminate fruit and other fructose-rich foods from their diet were rewarded with an improvement in symptoms, Choi says.
While not as well known as lactose intolerance, fructose intolerance is quite common, affecting one-third to one-half of patients with symptoms of IBS, Choi says.
The researchers tested 80 patients with suspected IBS; 30 were found to be fructose intolerant. The patients were taught what foods are high in fructose and urged to avoid them.
After one year, interviews with 26 of the patients showed that only one-half stuck to the fructose-restricted diet, Choi says.
But those who did stick with the program reported significantly less abdominal pain, bloating, and diarrhea than before changing their diets, he says. Not surprisingly, those who cheated on their diets showed no improvement in symptoms.
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Avoiding fructose is no easy task, says Kevin W. Olden, MD, associate professor of medicine in the division of gastroenterology at the Mayo Clinic in Scottsdale, Ariz. High-fructose corn syrup is a hidden ingredient in everything from cola to lemonade, he says.
Richard G. Locke III, also of the Mayo Clinic, says he wonders whether patients in the study really had IBS. Fructose intolerance can cause pain, bloating, and diarrhea — the same symptoms associated with irritable bowel syndrome.
“We used to think people who were intolerant to milk had IBS, but now we know they have lactose intolerance,” Locke says. “The same thing could be happening here. It’s a matter of labeling.”
The important thing is to know that fructose can cause these symptoms, says Yuri A. Saito, MD, MPH, also of the Mayo Clinic. “Most people are not even aware of this.”
In the second study, Saito and colleagues in the division of gastroenterology and hepatology found that people with IBS tend to reach for high-fat, low-carb foods. These dietary factors may contribute to some of the symptoms suffered by gastrointestinal disorders such as IBS.
They are also significantly more likely to suffer from food allergies than people who don’t have gastric woes, the study suggests.
The researchers studied 221 Minnesotans, about half of whom suffered from IBS or other gastrointestinal problems. All the participants filled out detailed questionnaires that asked about their diet, and about half of those in each group also kept a diet diary for one week itemizing exactly what they ate and when.
The study showed that fat comprised a greater proportion of the total calories taken in by people with IBS each day for healthy people. Carbohydrates, on the other hand, accounted for a lower proportion of their total caloric intake.
No significant differences were found for protein, fiber, iron, calcium, niacin, or vitamins B, C, D, or E.
Saito says further studies are needed to look at whether fat causes gastrointestinal symptoms in people with IBS.
In the meantime, she does not recommend any blanket change in diet recommendations. Instead, people who suffer from IBS should work with a doctor, nurse, or nutritionist to uncover any foods that make them feel worse.
Olden, who was not involved with the study, agrees. “I advise my patients to eat what they enjoy. If they identify a food that makes them feel sicker, they should not eat that food. “But you can’t tell everyone not to eat cornflakes.”
SOURCES: The 68th Annual Scientific Meeting of the American College of Gastroenterology, Baltimore, Oct. 12-15, 2003. Young K. Choi, MD, University of Iowa, Iowa City. Richard G. Locke III, associate professor of medicine, Mayo Clinic, Rochester, Minn. Kevin W. Olden, MD, associate professor of medicine, Mayo Clinic, Scottsdale, Ariz. Yuri A. Saito, MD, MPH, Mayo Clinic, Rochester, Minn.
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