Scand J Gastroenterol.?2023 Jun 29;1-12.?doi: 10.1080/00365521.2023.2228955.Online ahead of print. 

Hanna Fjeldheim Dale?1?2,?Sissi Christiane Stove Lorentzen?2,?Tonje Mellin-Olsen?2,?Jørgen Valeur?1?3 

Author information

1Unger-Vetlesen Institute, Lovisenberg Diaconal Hospital, Oslo, Norway. 

2Department of Clinical Support, Lovisenberg Diaconal Hospital, Oslo, Norway. 

3Department of Medicine, Lovisenberg Diaconal Hospital, Oslo, Norway. 

Abstract

Background:?Diet is one of the main modulators of the gut microbiota, and dietary patterns are decisive for gut-microbiota-related diseases, including irritable bowel syndrome (IBS). The low-FODMAP diet (LFD) is commonly used to treat IBS, but its long-term effects on microbiota, symptoms and quality of life (QoL) are unclear. Alternative dietary strategies promoting beneficial gut microbiota, combined with reduced symptoms and improved QoL, are therefore of interest. 

Aims:?To review current evidence on the diet-microbiota-interaction as a modulator of IBS pathophysiology, and dietary management of IBS, with particular emphasis on strategies targeting the gut microbiota, beyond the LFD. 

Methods:?Literature was identified through PubMed-searches with relevant keywords. 

Results:?Dietary patterns with a low intake of processed foods and a high intake of plants, such as the Mediterranean diet, promote gut microbiota associated with beneficial health outcomes. In contrast, Western diets with a high intake of ultra-processed foods promote a microbiota associated with disease, including IBS. Increasing evidence points towards dietary strategies consistent with the Mediterranean diet being equal to the LFD in alleviating IBS-symptoms and having a less negative impact on QoL. Timing of food intake is suggested as a gut microbiota modulator, but little is known about its effects on IBS. 

Conclusions:?Dietary recommendations in IBS should aim to target the gut microbiota by focusing on improved dietary quality, considering the impact on both IBS-symptoms and QoL. Increased intake of whole foods combined with a regular meal pattern and limitation of ultra-processed foods can be beneficial strategies beyond the LFD.