A new matched case-control study found that adherence to the Mediterranean diet and the Prime Diet Quality Score are inversely associated with newly diagnosed irritable bowel syndrome risk among Iranian adults.

In the study, in Frontiers in Medicine, investigators examined 170 patients with newly diagnosed irritable bowel syndrome (IBS) and 340 age- and sex-matched controls to examine the relationship between dietary patterns and IBS risk. They found that individuals with higher adherence to the Mediterranean diet had a 51% lower risk of IBS, and those with a higher Prime Diet Quality Score (PDQS) showed a 59% lower risk of IBS compared with participants with lower scores.

The associations remained significant after adjusting for potential confounders, including total energy intake, marital status, employment status, anxiety scores, education level, smoking habits, physical activity, and other variables.

Dietary pattern associations varied across IBS subtypes. Higher adherence to both dietary patterns was inversely associated with diarrhea-predominant IBS (IBS-D) and mixed IBS (IBS-M), but no statistically significant associations were observed for constipation-predominant IBS (IBS-C) or unclassified IBS (IBS-U).

The investigators suggested multiple mechanisms for the protective effects, including enhanced gut microbiota diversity, reduced inflammation from polyphenols in Mediterranean diet foods, and improved gut-brain axis function.

Study limitations included the case-control design that couldn't establish causality, potential recall bias in self-reported dietary intake, and reliance on self-reported symptom assessment rather than clinical or laboratory diagnostic measures.

The study authors concluded: "These findings suggest a potential role of these dietary patterns in modulating IBS risk, although causal relationships cannot be established from this study."

The authors declared having no competing interests.