Diets low in FODMAPS (fermentable oligo-, di-, monosaccharides and polyols) are established as effective treatments for adults with irritable bowel syndrome (IBS). After just four weeks on a low FODMAP diet, patients with IBS reported improvement in bloating, abdominal pain, diarrhea, and stool urgency with more than 60% reporting meaningful improvement in quality of life. But would the same positive results be seen in children? Guided by the often-cited adage that “children are not small adults,” it’s important to have research conducted specifically in children and adolescents before applying any particular approach to these age groups. A study published last month from New Zealand’s University of Otago indicates that yes, low-FODMAP diets are safe and effective for younger people.

The study, “Low FODMAP diet in children and adolescents with functional bowel disorder: A clinical case note review,” was relatively small (just 29 subjects) and conducted over only four weeks but still provides useful information. It was a retrospective clinical case review of subjects age 4 to 17 diagnosed with a functional bowel disorder. Looking at symptoms, 76% and 41% experienced abdominal pain or distension, respectively. 27% had diarrhea while 21% had constipation and 24% alternated between these. 10% experienced acid reflux. These things are unpleasant enough when they occur in adults who may be able to use willpower to overcome them and get through the tasks of their day, but children may have a more difficult time compensating, which could lead to behavioral problems and, quite simply, just feeling lousy and not enjoying a carefree and fun childhood.

Results were impressive. Within just the four weeks of FODMAP restriction, complete resolution of gastrointestinal symptoms was reported by 11 of 12 subjects with bloating (92%), 87% of those with diarrhea (13 of 15) and 77% with abdominal pain (17 of 22). Twenty‐three participants (70%) reported at least some improvement in symptoms. Overall, the diet was most effective in those with flatulence, diarrhea, and abdominal pain and distention. While most subjects reported a substantial improvement in functional bowel disorder symptoms, only one subject (out of seven) with stress and/or anxiety reported complete resolution of this symptom, with four reporting partial resolution. Out of eight subjects with constipation, three experienced complete resolution and three reported partial resolution. Out of ten subjects who reported having low energy levels at baseline, eight (80%) reported some degree of improvement after FODMAP restriction reported, with half of these (40%) reporting “substantial” improvement. 

Based on food, beverage, and symptom diaries subjects were asked to keep throughout the elimination diet period, fructans were identified as the most common cause of symptoms. 67% of subjects were found to have fructan intolerance, followed by 56% intolerant to lactose, and 7% each for polyols, fructose and galactose polyols. Fructans are linear or branched fructose polymers. Small molecules (2-9 fructose units) are called oligofructose; larger fructans (> 10 units) are called inulins. High fructan foods include wheat, onions, garlic, cabbage, brussels sprouts, artichoke, asparagus, ripe bananas, raisins, chicory root, and kidney, lima and black beans. While it might be easy to get kids to avoid onions, cabbage, and lima beans (some might be happy to stop eating those), eliminating childhood favorites like wheat, bananas and raisins is a taller order. And for people with irritable bowel conditions, perhaps “an apple a day” isn’t such great advice.

It’s possible that fructan intolerance is the true cause of what may be misdiagnosed as non-celiac gluten sensitivity. By avoiding wheat, individuals who adopt a gluten-free diet eliminate the source of about 70% of the fructans in the American diet.

Bringing this into real world relevance, the study authors helpfully provided information about ease of adherence to the diet and satisfaction with outcomes. After all, it doesn’t matter how effective an intervention is if it’s impossible to stick to. In this study, 86% of participants agreed or strongly agreed that the diet was easy to stick to and 55% were satisfied with their symptom improvement. In a bit of a reality check, 59% reported that they would not be interested in making additional changes to their diet to further to improve symptoms. Understandable, considering a low-FODMAP diet calls for eliminating or drastically reducing consumption of what and wheat-containing products, bananas, apples, cherries, pears, peaches, watermelon, honey, cow dairy products, chickpeas, lentils, and the sugar alcohols found in many sugar-free products including gum and mints (sorbitol, mannitol, xylitol, maltitol).

Following a low-FODMAP diet may not be easy—for adults or for children—but the possibility of complete or even partial resolution of uncomfortable symptoms may make it worth it. When children need a restrictive diet, it may be best for a parent or other family member in the household to follow the diet as well and be a “diet buddy” so the child doesn’t feel like the odd one out at restaurants or the family dinner table. Moral support can go a long way toward making this kind of approach easier.