By Peter Loftus
People suffering from a common but tough-to-treat gut disorder called IBS are discovering a growing set of treatment alternatives.
The U.S. Food and Drug Administration has approved two new drugs in the past year for the disorder, known as irritable bowel syndrome, which involves chronic diarrhea, constipation or both, along with abdominal cramping. It is estimated to affect about 12% of Americans, more often women than men and typically in people younger than 45, according to the Mayo Clinic.
Meanwhile, a diet dubbed “Low Fodmap,” which originated in Australia more than a decade ago, has spread in the U.S. in recent years. It is gaining acceptance from gastroenterologists and dietitians as some small clinical trials bolster evidence of its effectiveness in reducing IBS symptoms. The diet eliminates or reduces foods with certain types of sugars that have been found to trigger symptoms.
“I definitely think the options are better and that patients with mild symptoms can do better,” says Dr. Lin Chang, director of the digestive health and nutrition clinic at UCLA‘s David Geffen School of Medicine. “I think the question is, what treatment do you use in what patient?”
Unlike more serious gut conditions, such as Crohn’s disease or ulcerative colitis, IBS doesn’t alter bowel tissue or put patients at increased risk for colorectal cancer. But it causes pain, embarrassment and anxiety in sufferers, who often limit their activities only to places where a toilet will be close by.
“It’s really common, and I think it’s underappreciated in terms of the burden it creates for affected individuals,” says Dr. William Chey, a professor of internal medicine specializing in gastrointestinal disorders at the University of Michigan.
Older treatment options have included antispasmodic drugs like dicyclomine and low-dose antidepressants such as amitriptyline. Dietary approaches have included adjustments to fiber intake. But these options don’t work for everyone.
In May 2015, the FDA approved two new drugs for treatment of IBS in which diarrhea is predominant: Viberzi, made by Allergan PLC, and Valeant Pharmaceuticals InternationalInc.’s Xifaxan. For IBS with constipation, the FDA approved Allergan’s Linzess in 2012.
Dr. Leslie Yang, a University of Chicago gastroenterologist, says the new drugs have shown some level of efficacy in clinical trials, but it can take some trial and error to figure out which will work best for an individual patient. “It’s more of an art than a science,” she says.
The new drugs aren’t without side effects. Viberzi can increase the risk for muscle spasms near the digestive tract that can lead to inflammation of the pancreas. Dr. Chang of UCLA says doctors should avoid prescribing it to people who abuse alcohol.
A dietary approach to easing that burden has gained steam in the U.S. as physicians like Dr. Chey listen to patients who would rather avoid taking a prescription drug, he says. The University of Michigan, University of Chicago and Stanford University are among the academic medical centers that have embraced the low Fodmap diet as an option for patients. Some have hired dietitians specializing in gastrointestinal disorders to help guide patients.
Fodmap is an acronym for “fermentable oligosaccharides, disaccharides, monosaccharides and polyols”—a group of sugars and other food ingredients poorly absorbed in the gut. Patients are advised to restrict eating foods with high amounts including asparagus, apples, cow’s milk and certain beans. They are encouraged to eat foods with lower amounts, including zucchini, bananas, certain cheeses and gluten-free breads and cereal.
“This helps to at least minimize the diarrhea, minimize the gas and bloating,” says Lori Welstead, a University of Chicago dietitian. “So this can really help with the quality of life for patients.”
Researchers at Monash University in Melbourne, Australia, developed the low-Fodmap diet and have conducted clinical trials to test its efficacy. In a 38-person study, those on the low-Fodmap diet had reduced gastrointestinal symptoms versus those on a typical Australian diet, according to results published in the medical journal Gastroenterology in 2014.
In a U.S. study of 33 children with IBS conducted by researchers at Baylor College of Medicine in Houston, a low-Fodmap dietreduced the frequency of abdominal paincompared with a traditional American diet, according to results published in Alimentary Pharmacology and Therapeutics last year.
Morgan Blenkhorn, a 21-year-old student at Grand Valley State University in Allendale, Mich., says the low-Fodmap diet has given her relief from severe IBS symptoms. She first started having problems after a food-poisoning incident in high school. Her anxiety about having to use the bathroom frequently kept her from many activities including graduation parties, she says.
She discovered the low-Fodmap diet after visiting Dr. Chey at the University of Michigan in 2013, and it has vastly reduced her symptoms, she says. Last summer she taught English in the Netherlands and made a side trip to Germany—something she would never have considered when her IBS was worse.
“It changed my life completely,” she says. “I don’t think that I could have even gotten this far in college without drastic change.”
A caveat with the low-Fodmap diet: There is emerging evidence that it alters the diverse population of microbes in the gut. This could have long-term implications, because some gut microbes are believed to have health benefits. A Monash-sponsored study of 33 people found that the low-Fodmap diet reduced abundance of bacteria in the gut, according to results published in the medical journal Gut in 2014.
Emma Halmos, a dietitian at Monash who helped conduct the study, says more research is needed to show whether the microbial alterations can harm health. She says it underscores the need for healthy people to avoid the low-Fodmap diet, and for patients on the diet to try to reintroduce specific foods if they don’t trigger symptoms.