Traditional dietary advice most preferred for IBS

Traditional dietary advice, gluten-free diet (GFD), and low FODMAP diet (LFD) are all effective dietary approaches to reducing symptoms in patients with irritable bowel symptom (IBS), but traditional dietary advice is the pick of the bunch in terms of cost and convenience, according to a team of UK-based researchers.

The GFD or LFD, on the other hand, should be reserved according to specific patient preferences and with specialist dietetic input, they added.

In their study, the researchers randomized 101 patients (mean age 37 years, 71 percent female) with Rome IV-defined nonconstipated IBS to one of the following dietary therapies—traditional dietary advice (n=35), LFD (a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols; n=35), or a GFD (n=35)—for 4 weeks. A total of 33 patients in each arm completed the study.

At week 4, the number of patients who achieved the primary endpoint of clinical response (defined by ≥50-point reduction in IBS symptom severity score [IBS-SSS]) was comparable across all treatment arms: 42 percent with traditional dietary advice, 55 percent with LFD, and 58 percent with GFD (p=0.43). The responders showed similar improvements in IBS-SSS items regardless of their allocated diet. [Clin Gastroenterol Hepatol 2022;doi:10.1016/j.cgh.2022.02.045]

In terms of acceptability, traditional dietary advice emerged as the most patient-friendly, with patients finding the approach to be cheaper (p<0.01), less time-consuming to shop (p<0.01), and simpler to follow when eating out (p=0.03) compared with the GFD and LFD. The dietary advice was also easier to incorporate into daily life than the LFD (p=0.02).

All treatment arms had similar overall reductions in micro- and macronutrient intake. However, the LFD arm showed the greatest reduction in total FODMAP content (from 27.7 g/day at baseline to 7.6 g/day at week 4), accordingly, as compared with the GFD (from 27.4 g/day to 22.4 g/day) and traditional dietary advice (from 24.9 g/day to 15.2 g/day).

Changes in stool dysbiosis index likewise did not significantly differ across the treatment arms, with 22–29 percent of patients having reduced dysbiosis, 35–39 percent showing no change, and 35–40 percent having increased dysbiosis.

“On balancing the efficacy and acceptability of dietary therapies, plus the demands they place upon healthcare services, we suggest traditional dietary advice be considered first,” according to the researchers.

LFD and GFD expensive, harder to follow

Traditional dietary advice involves the adoption of healthy, sensible eating patterns, such as having regular meals, never eating too little/too much, and maintaining adequate hydration. It also advocates cutting the intake of the following: 1) alcohol, caffeine, and fizzy drinks; 2) fatty, spicy, and processed foods; 3) fresh fruits to a maximum of three per day; 4) fibre and other commonly consumed gas-producing foods (eg, beans, bread, and sweeteners, among others). Finally, the patients are advised to address any perceived food intolerances like dairy.

LFD, on the other hand, purges all FODMAPs in the diet for 4–6 weeks, followed by their gradual reintroduction and personalization. FODMAPs are short-chain fermentable carbohydrates found in a variety of foods and contribute to an increase in intestinal fluid and colonic gas that induces gastrointestinal symptoms in individuals with visceral hypersensitivity. [Gut 2021;70:1214-1240]

Meanwhile, GFD has seen an uptake among individuals without coeliac disease globally, with about 10 percent of the population reporting that gluten-based products cause intestinal symptoms compatible with IBS. [Am J Gastroenterol 2018;113:945-948]

“The LFD and GFD, while beneficial, are costlier, harder to follow, and more inconvenient. Furthermore, their implementation requires specialized and extensive dietetic input which incurs a substantial burden on healthcare services,” the researchers noted.

As costs are critical determinants of IBS treatment value to patients and providers, the researchers recommended LFD and GFD as secondary options and urged consideration of alternate cheaper options such as antispasmodics and neuromodulators.

“This is the first randomized trial comparing the efficacy and convenience of traditional dietary advice, LFD and GFD in nonconstipated IBS. The pragmatic study design, whereby the responsibility was left upon patients to undertake the diets following appropriate education, means our findings can be generalized,” the researchers said.

Currently, traditional dietary advice is the first-line dietary therapy for IBS within the UK, while LFD comes second. In North America, LFD is the first choice. Neither the British nor the North American guidelines recommends a GFD. [Gut 2021;70:1214-1240; J Can Assoc Gastroenterol 2019;2:6-29; ACG 2021;116:17-44]