‘Complicated’ relationship exists between irritable bowel syndrome, low FODMAP diet
PHILADELPHIA — The FODMAP diet may offer benefits for some patients with irritable bowel syndrome, but is not a fit for all patients, a speaker at the American College of Physicians Internal Medicine Meeting suggested.
Patients following the low-FODMAP eating pattern (fermentable oligo, disaccharides, monosaccharaides and polyols) can consume certain fruits, vegetables, meats and nuts; most gluten-free pasta products and lactose-free dairy products; certain cheeses; and artificial sweeteners that do not end in -ol, according to the U.S. Department of Agriculture website.
Though pharmaceutical options such as Amitiza (lubiprostone, Takeda), Linzess (linaclotide, Allergan) and Trulance (plecanatide, Synergy Pharmaceuticals) have strong recommendations and high or moderate levels of evidence to support their use as IBS treatment, “low FODMAP ... is becoming increasing popular for patients with IBS. Though there are certainly patient subsets who would absolutely benefit from it, we don’t know how to pre-emptively identify them yet,” Brooks D. Cash, MD, FACP, chief of gastroenterology, hepatology and nutrition at McGovern Medical School at the University of Texas Health Science Center, told attendees.
“The theory behind the low FODMAP diet is both somewhat complicated and also pretty simple,” Cash continued. “The low FODMAP diet produces an osmotic effect from poorly digested carbohydrates that impacts motility, biomass and the microbiome, and perhaps leads to gastrointestinal symptoms such as bloating, flatulating, visceral sensations and cognitive symptoms. Our microbiome loves these types of foods and that’s where the foods make a lot of gas as they digest or metabolize these poorly digested carbohydrates.”
Cash discussed the limited research examining the link between low FODMAP and IBS.
In a study of approximately 80 participants, where about half ate a low FODMAP diet and the others ate a modified NICE diet (eating healthy foods, decreasing or eliminating alcohol and fats and avoiding huge portions and eating late at night), more of those following low FODMAP saw significant improvements in their abdominal pain, bloating and scores on quality of life questionnaire, but global IBS outcomes between the groups were not significantly different. In a second study, 19 in the low-FODMAP group had a 50% or greater reduction in their IBS severity vs. 17 in the modified NICE group.
“These studies are hard to recruit for, and it can be hard to mask the foods. ... This data is somewhat waffly in terms of significance, but it shows how low FODMAP can play an important role in these patients,” he said.
“But that’s not to say there are not issues with low FODMAP,” Cash continued. “What is the cutoff for FODMAP content? Resources differ on low FODMAP diets, most patients can’t stick to the diet, there are theoretical nutritional issues with its longterm use, and it can be time-consuming to counsel patients.”
The complexity and improved understanding of how diet affects health shows the need for consultation when suggesting such a diet, he said.
“When I was a fledging gastroenterologist I used to [show the patient] Google and say, ‘here try this.’ I know now that is not fair to our patients and I no longer do this. I would urge you all to do what I do: use a dietician or nutritionist to help with these patients,” Cash said. – by Janel Miller
References: Cash BD. “Irritable bowel syndrome: New hope for an old problem.” Presented at: American College of Physicians Internal Medicine Meeting; April 11-13, 2019; Philadelphia.
U.S. Department of Agriculture. “Digestive diseases and disorders.” https://www.nal.usda.gov/fnic/digestive-diseases-and-disorders. Accessed April 15, 2019.
Disclosures: Cash reports no relevant financial disclosures.