Clin Gastroenterol Hepatol. 2023 Jul 28;S1542-3565(23)00574-8.doi: 10.1016/j.cgh.2023.07.012. Online ahead of print.

Ellie Chen ¹, Swapna Mahurkar-Joshi ², Cathy Liu ², Nancee Jaffe ¹, Jennifer Labus ², Tien Dong ³, Arpana Gupta ², Shravya Patel ⁴, Emeran A Mayer ², Lin Chang ⁵

Author information

¹University of California Los Angeles Division of Digestive Diseases, Los Angeles, CA, United States.

²University of California Los Angeles Division of Digestive Diseases, Los Angeles, CA, United States; G. Oppenheimer Center for Neurobiology of Stress and Resilience, Los Angeles, CA, United States; UCLA Goodman-Luskin Microbiome Center, Los Angeles, CA, United States.

³University of California Los Angeles Division of Digestive Diseases, Los Angeles, CA, United States; UCLA Goodman-Luskin Microbiome Center, Los Angeles, CA, United States.

⁴University of California Los Angeles, Los Angeles, CA, United States.

⁵University of California Los Angeles Division of Digestive Diseases, Los Angeles, CA, United States; G. Oppenheimer Center for Neurobiology of Stress and Resilience, Los Angeles, CA, United States; UCLA Goodman-Luskin Microbiome Center, Los Angeles, CA, United States. Electronic address: linchang@mednet.ucla.edu.

Abstract

Background: Low adherence to Mediterranean Diet (MD) has been shown to be associated with a higher prevalence of irritable bowel syndrome (IBS), but its association with IBS symptoms is not established. We aim to assess the association between MD and IBS symptoms, identify components of MD associated with IBS symptoms, and determine if a symptom-modified MD is associated with changes in the gut microbiome.

Methods: 106 Rome +IBS and 108 health control (HCs) participants completed diet history and gastrointestinal symptom questionnaires. Adherence to MD was measured using Alternate Mediterranean Diet (aMED) and Mediterranean Diet Adherence Screener (MEDAS). Sparse partial least squares analysis identified MD food items associated with IBS symptoms. Stool samples were collected for 16S ribosomal RNA gene sequencing and microbial composition analysis in IBS subjects.

Results: aMED and MEDAS scores were similar between IBS and HCs and did not correlate with IBS-SSS, abdominal pain or bloating. Amongst IBS participants, a higher consumption of fruits, vegetables, sugar, and butter were associated with a greater severity of IBS symptoms. Multivariate analysis identified several MD foods to be associated with increased IBS symptoms. A higher adherence to symptom-modified MD was associated with a lower abundance of potentially harmful Faecalitalea, Streptococcus, Intestinibacter and higher abundance of potentially beneficial Holdemanella from the Firmicutes phylum.

Conclusion: A standard MD was not associated with IBS symptom severity, although certain MD foods were associated with increased IBS symptoms. Our study suggests that standard MD may not be suitable for all IBS patients and likely needs to be personalized in those with increased symptoms.