There’s growing evidence that a Mediterranean diet can provide relief from symptoms of irritable bowel syndrome (IBS), offering people more variety and easier adherence than the current frontline treatment of a low-FODMAP plan to treat the condition.
University of Sheffield researchers put the two diet plans head-to-head in a randomized trial involving 110 adults, aged 18-65 years, with IBS. Half the cohort followed a six-week low-FODMAP plan and half were prescribed a Mediterranean diet. After the six weeks, the participants were assessed on efficacy, which was defined as a 50-point or greater reduction on the IBS Symptom Severity Scale (IBS-SSS). In addition to this, the researchers also evaluated secondary outcomes, which included other changes in the IBS-SSS scores, psychological health, quality of life, diet satisfaction and adherence.
If you’re one of the estimated 15% of the population who suffers from IBS, you may be familiar with the low-FODMAP intervention to relieve symptoms. FODMAP is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides and polyols, a group of fermentable short-chain carbohydrates that are known to be more difficult to digest. Typically, the diet has three stages – elimination, reintroduction and maintenance – with the first, where individuals cut out high-FODMAP foods such as dairy, high-fructose corn syrup, mangoes, cauliflower, and most beans, being quite restrictive. And while adherence is widely reported as high, and the results beneficial, people have found challenges with replacing eliminated staples and report lower energy during this stage.
The Mediterranean diet, on the other hand, is characterized by high consumption of fruits, vegetables, whole grains, legumes, fish and healthy fats, particularly olive oil. There is some evidence that the diet’s fiber-rich plant foods help support gut microbiota diversity, and omega-3 fatty acids from fish and monounsaturated fats has been associated with reduced intestinal inflammation. However, its efficacy in managing IBS is not well understood.
In this latest study, researchers found that after six weeks, a 50-point or greater reduction in IB-SSS score was achieved by 62% of those assigned the Mediterranean diet, compared with 42% of participants eating the low-FODMAP plan. There was also a greater reduction in mean IBS-SSS score on the Mediterranean diet and frequency of abdominal pain was significantly improved among these participants, compared with the FODMAP cohort.
However, earlier this year, University of Michigan researchers found that the low-FODMAP diet to be marginally more effective (81.8% versus 73% on the Mediterranean diet for four weeks). The team noted at the time that symptom relief came at a cost, with trial participants reporting some challenges with the low-FODMAP plan.
“Restrictive diets, such as low FODMAP, can be difficult for patients to adopt,” said Prashant Singh, Michigan Medicine gastroenterologist and lead author on the April 2025 paper. “In addition to the issue of being costly and time-consuming, there are concerns about nutrient deficiencies and disordered eating when trying a low FODMAP diet. The Mediterranean diet interested us as an alternative that is not an elimination diet and overcomes several of these limitations related to a low FODMAP diet.”
In a 2024 Australian trial of 59 adults with IBS, researchers found that over six weeks, there was greater adherence for those on the Mediterranean diet, as well as improved gastrointestinal and psychological symptoms over that period.
While it’s too early to say definitively that one plan is better than the other for overall relief, researchers note that the Mediterranean diet “represents a viable first-line dietary intervention for IBS,” and warrants larger studies. What’s more, the diet could deliver other benefits beyond symptom relief, with existing evidence that it can help reduce the risk of heart disease, cancer, dementia and diabetes.
The study was published in the journal Annals of Internal Medicine.
Source: University of Sheffield via Scimex
