Restrictive diets offer greater symptom reduction vs. medical treatment in IBS patients
SAN DIEGO — Two restrictive diets were superior in reducing symptoms compared with optimized medical treatment alone in patients with irritable bowel syndrome, according to results presented at Digestive Disease Week 2022.
“There are several different treatment options that are effective in alleviating symptoms of IBS, and dietary treatment indeed can be encouraged as a first-line treatment option,” Sanna Nybacka, RD, PhD, of the department of molecular and clinical medicine at the University of Gothenburg in Sweden, told Healio. “Our findings support the current guidelines in treatment of IBS, where a positive diagnosis of IBS is crucial for a successful management of IBS and should be followed by general lifestyle intervention and dietary advice. Medical treatment should be guided by the patient’s symptom profile and preference as a second-line treatment option.”
Nybacka and colleagues randomly assigned 302 adult patients with IBS, all of whom had at least moderate IBS symptom severity (IBS-SSS 175), to receive one of three treatment options for 4 weeks: a diet with low total carbohydrate content (LCD); a diet combining low-fermentable oligo-, di- and monosaccharides and polyols (FODMAP) and traditional dietary advice (LFTD); or an optimized medical treatment (OMT) strategy. Food was delivered to patients weekly.
Investigators based the OMT on the predominant IBS symptom and previous experience of IBS pharmacological agents and evaluated IBS symptom severity before and after the treatment period. The proportion of patients with a reduction in IBS-SSS of at least 50 served as the primary endpoint.
Of the randomized participants, 295 were included in the intention-to-treat (ITT) analysis and 272 completed the intervention period.
According to researchers, all three interventions reduced the severity of IBS symptoms (P < .001, within groups), although there was a greater change in severity in the two dietary interventions compared with OMT. There was no significant difference between the two diets.
Results from ITT analysis demonstrated that 72% of patients in the LCD group met the primary endpoint, followed by 75% in the LFTD group and 58% in the OMT group (P = .025). In addition, there was a larger proportion of responders after LCD and LFTD compared with OMT (P = .042, P = .012, respectively). Further, even with stricter responder criteria (IBS-SSS reduction 100 and 50%, respectively) and proportion of patients with mild IBS symptoms (IBS-SSS < 175) after the intervention, there was a larger proportion of responders in the dietary groups.
“We will however need to analyse the long-term follow-up data to make sure that the treatments are safe, effective and applicable to patients,” Nybacka said. “We will also need to elucidate which pre-treatment factors can predict a positive treatment outcome, in order to give more personalized treatment to patients.”
Perspective
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I am happy to see more diet intervention-focused studies, as they can be challenging to conduct. In this study completed by Nybacka and colleagues, meals of all three diet interventions being evaluated were provided to participants to better control variables and obtain accurate results for measuring improvement of symptoms.
In my experience, the low-FODMAP (fermentable, oligo-, di- and monosaccharides and polyols) diet can be hard to follow for some individuals. It is important to conduct a thorough assessment to determine likelihood of patient compliance and willingness to follow a restrictive diet. I will often start with a lower carbohydrate diet, similar to the diet outlined in this study, by making current food swaps for lower fermentable carbohydrate options. If this intervention does not yield results, we will continue to the strict, low-FODMAP diet. This study found positive improvement in symptoms with both dietary interventions, and with this information it is reasonable to start with a diet that is easier to follow, and then advancing to a stricter low-FODMAP diet, if needed.
The AGA guidelines address the role of diet and the treatment of IBS: “Of the available options, the low-FODMAP diet is the most evidence-based dietary intervention for the treatment of IBS.” The low-FODMAP diet has been reported to improve symptoms in 50% to 70% of patients with IBS. It is important to recognize that the low-FODMAP diet is composed of three phases: elimination, reintroduction and personalization. A patient should not be left in the elimination phase for longer than 6 weeks. The long-term effects are unknown at this time but can be predictive of disordered eating patterns and deficiencies. Long-term elimination can result in deficiencies in vitamins, minerals and naturally occurring antioxidants, resulting in negative changes in the intestinal microbiota. It is important to complete all three phases.
So, what is the role of diet in the pathophysiology of IBS? Diet can be directly related to intentional distention and altering the intestinal microbiota. The amount of food and liquid and gas production caused by the fermentation of food will cause the intestine to distend. A diet that is high in FODMAP foods can increase the osmotic pressure in the gut and act as a prebiotic for certain gas-producing bacteria. Patients with IBS also are at risk for having lower amounts of GI hormone cells that contribute to functions like motility, secretion and absorption, and appetite. Completing the low-FODMAP elimination phase can help restore the balance of these cells in the gut.
If you feel like your patients would benefit from a low-FODMAP diet, consider referring them to a registered dietitian. This diet can be hard to follow without guidance, and when not done properly, patients may still experience symptoms. The low-FODMAP diet has been shown to be successful in patients with IBS and, when appropriate, should be considered as a treatment option.
References:
- Chey W, et al. Gastroenterology. 2022;doi:10.1053/j.gastro.2021.12.248.
- El-Salhy M, et al. Indian J Gastroenterol. 2021;doi:10.1007/s12664-020-01144-6.
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Nybacka S, et al. Abstract 684. Presented at: Digestive Disease Week; May 21-24, 2022; San Diego (hybrid meeting).
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