Diets low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols reduced functional gastrointestinal symptoms in patients with irritable bowel syndrome.
The finding, published by Dr. Emma P. Halmos in the January issue of Gastroenterology (2013; [doi:10.1053/j.gastro.2013.09.046]), confirms that the diet’s "growing popularity" is warranted, and supports its use as a first-line therapy for IBS.
Dr. Halmos of Monash University, in Box Hill, Australia, and her colleagues looked at 30 patients with IBS and 8 healthy controls.
At baseline, all patients recorded their normal, daily dietary intake in a food diary for 1 week, as well as IBS symptoms.
Patients were then randomized to receive either 21 days’ worth of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs), meaning less than or equal to 5 grams per sitting of these ingredients, or food representing a typical Australian diet.
For example, instead of a breakfast of "wheat biscuit–type cereal with 1/2 cup lactose-free milk, two slices wheat toast," the low-FODMAP adherents were given one cup corn flakes with 1/2 cup lactose-free milk and two slices of spelt toast.
Almost all food was provided, including three main meals and three snacks daily.
Next, there was a washout period during which each participant resumed their usual diet and then crossed-over to the alternate, which was not begun until the symptoms had returned to the same level as baseline.
Patients were prohibited from taking any other therapies for IBS during the study period, nor were they permitted to take any pharmacologic agents to alter their symptoms, including laxatives or antidiarrheals.
At baseline, the mean overall gastrointestinal symptoms score for IBS patients was 36.0 mm on the Visual Analogue Scale.
By the final 14 days of the intervention, IBS patients on the low-FODMAP diet reported a mean overall symptom score of 22.8 mm (P less than .001, compared with baseline).
That was in contrast to the 44.9 mm among IBS patients on the typical Australian diet (P less than .001, compared with baseline), with the difference between the two scores also reaching statistical significance (P less than .001).
Moreover, 21 of 30 IBS patients reported improvements of 10 mm or more on the low-FODMAP diet, wrote the authors.
Healthy controls, meanwhile, had very low scores at baseline (17.8 mm), and there was no change in symptoms on the low-FODMAP or typical Australian diets.
The authors also assessed adherence, as recorded in food diaries. IBS patients were adherent for a median 41 of the 42 days of the combined diets, and healthy controls were adherent for the entire 42 days.
Additionally, "If adherence for at least 17 days of the 21 days of controlled diet (greater than 81% of the days) was arbitrarily considered compliant, then all participants were adherent to the typical Australian diet, and 80% of IBS participants (24 of 30) and 100% of healthy controls were adherent to the low-FODMAP diet," wrote the authors.
According to the authors, one of the strengths of this study was in comparing the low-FODMAP diet with a typical Australian diet, as opposed to an intentionally very-high FODMAP regimen, as earlier studies have done.
They added that providing almost all food to participants facilitated a high degree of adherence.
However, "In life, the low-FODMAP diet is dietitian taught. Dietary restriction would have more varying degrees of compliance and depend on the patients’ degree of understanding, food choices, and motivation for altering dietary habits, as well as the dietitians’ advice on level of FODMAP restriction required," they wrote.
Dr. Halmos disclosed that two coauthors have previously published books on food intolerances and a low-FODMAP diet. They wrote that the study was supported by the National Health and Medical Research Council of Australia, the Les and Eva Erdi Foundation, and by a scholarship from Monash University.