Effects of the Mediterranean Diet on Gut Microbiota and Cardiometabolic Outcomes in Adults with Overweight or Obesity: A Systematic Review of Randomized Controlled Trials (RCT)
DOI:
https://doi.org/10.36568/jone.v4i4.788Keywords:
Mediterranean Diet, Gut Microbiota, Obesity, Overweight, Randomized Controlled Trial, Systematic ReviewAbstract
Obesity is associated with metabolic dysfunction and alterations in the gut microbiota. The Mediterranean diet (MD), rich in plant-based foods, dietary fiber, polyphenols, and unsaturated fats, may influence microbial composition and cardiometabolic health. This systematic review evaluated the effects of MD interventions on gut microbiota composition, microbial functions, and cardiometabolic outcomes in adults with overweight or obesity. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines and registered in PROSPERO (CRD420251155212). Randomized controlled trials examining MD interventions in adults with overweight or obesity were eligible. We used the Cochrane Risk of Bias 2 (RoB 2) tool to assess the risk of bias and the GRADE approach to evaluate the certainty of evidence. Five publications representing three independent cohorts were included. A narrative synthesis was performed due to overlapping study populations, methodological heterogeneity, and variability in microbiome assessment methods. MD interventions were associated with changes in specific gut microbial taxa, including short-chain fatty acid-producing bacteria such as Faecalibacterium, Roseburia, and Butyricicoccus. Additional studies reported changes in microbial diversity and cardiometabolic markers. However, the certainty of evidence was rated low to very low due to study design limitations, small sample sizes, heterogeneity, and potential risk of bias. In conclusion, MD interventions may influence selected gut microbial taxa and cardiometabolic outcomes in adults with overweight or obesity, though further well-designed randomized controlled trials are required to establish clinical relevance.
References
Lin K, Zhu L, Yang L. Gut and obesity/metabolic disease: Focus on microbiota metabolites. MedComm (Beijing) 2022;3(3); doi: 10.1002/mco2.171.
Fan Y, Pedersen O. Gut microbiota in human metabolic health and disease. Nat Rev Microbiol 2021;19(1):55–71; doi: 10.1038/s41579-020-0433-9.
Rinninella E, Raoul P, Cintoni M, et al. What is the Healthy Gut Microbiota Composition? A Changing Ecosystem across Age, Environment, Diet, and Diseases. Microorganisms 2019;7(1):14; doi: 10.3390/microorganisms7010014.
Muralidharan J, Moreno-Indias I, Bulló M, et al. Effect on gut microbiota of a 1-y lifestyle intervention with Mediterranean diet compared with energy-reduced Mediterranean diet and physical activity promotion: PREDIMED-Plus Study. Am J Clin Nutr 2021;114(3):1148–1158; doi: 10.1093/ajcn/nqab150.
Shah S, Mu C, Shen-Tu G, et al. Influence of dietary components on the gut microbiota of middle-aged adults: the gut-Mediterranean connection. BMC Microbiol 2025;25(1):573; doi: 10.1186/s12866-025-04170-6.
Mustikasari MI, Wardhana MP, Indriani A, et al. Spontaneous Conception and Favorable Obstetric Outcome in a Patient with PCOS and Class II Obesity: A Case Report. Health Dynamics 2025;2(4):160–165; doi: 10.33846/hd20404.
Estruch R, Ros E. The role of the Mediterranean diet on weight loss and obesity-related diseases. Rev Endocr Metab Disord 2020;21(3):315–327; doi: 10.1007/s11154-020-09579-0.
Nagpal R, Shively CA, Register TC, et al. Gut microbiome-Mediterranean diet interactions in improving host health. F1000Res 2019;8:699; doi: 10.12688/f1000research.18992.1.
Ghosh TS, Rampelli S, Jeffery IB, et al. Mediterranean diet intervention alters the gut microbiome in older people reducing frailty and improving health status: the NU-AGE 1-year dietary intervention across five European countries. Gut 2020;69(7):1218–1228; doi: 10.1136/gutjnl-2019-319654.
Perrone P, D’Angelo S. Gut Microbiota Modulation Through Mediterranean Diet Foods: Implications for Human Health. Nutrients 2025;17(6):948; doi: 10.3390/nu17060948.
Gallè F, Valeriani F, Cattaruzza MS, et al. Mediterranean Diet, Physical Activity and Gut Microbiome Composition: A Cross-Sectional Study among Healthy Young Italian Adults. Nutrients 2020;12(7):2164; doi: 10.3390/nu12072164.
Du Y, He C, An Y, et al. The Role of Short Chain Fatty Acids in Inflammation and Body Health. Int J Mol Sci 2024;25(13):7379; doi: 10.3390/ijms25137379.
Redruello-Requejo M, del Mar Blaya M, González-Reguero D, et al. Cross-Sectional Comparative Analysis of Gut Microbiota in Spanish Adolescents with Mediterranean and Western Diets. Nutrients 2025;17(3):388; doi: 10.3390/nu17030388.
Cumpston MS, McKenzie JE, Welch VA, et al. Strengthening systematic reviews in public health: guidance in the Cochrane Handbook for Systematic Reviews of Interventions , 2nd edition. J Public Health (Bangkok) 2022;44(4):e588–e592; doi: 10.1093/pubmed/fdac036.
Crocker TF, Lam N, Jordão M, et al. Risk-of-bias assessment using Cochrane’s revised tool for randomized trials (RoB 2) was useful but challenging and resource-intensive: observations from a systematic review. J Clin Epidemiol 2023;161:39–45; doi: 10.1016/j.jclinepi.2023.06.015.
Prasad M. Introduction to the GRADE tool for rating certainty in evidence and recommendations. Clin Epidemiol Glob Health 2024;25:101484; doi: 10.1016/j.cegh.2023.101484.
Brignardello-Petersen R, Guyatt GH. Assessing the certainty of the evidence in systematic reviews: importance, process, and use. Am J Epidemiol 2025;194(6):1681–1686; doi: 10.1093/aje/kwae332.
Haro C, Montes-Borrego M, Rangel-Zúñiga OA, et al. Two Healthy Diets Modulate Gut Microbial Community Improving Insulin Sensitivity in a Human Obese Population. J Clin Endocrinol Metab 2016;101(1):233–242; doi: 10.1210/jc.2015-3351.
Haro C, García‐Carpintero S, Rangel‐Zúñiga OA, et al. Consumption of Two Healthy Dietary Patterns Restored Microbiota Dysbiosis in Obese Patients with Metabolic Dysfunction. Mol Nutr Food Res 2017;61(12); doi: 10.1002/mnfr.201700300.
Meslier V, Laiola M, Roager HM, et al. Mediterranean diet intervention in overweight and obese subjects lowers plasma cholesterol and causes changes in the gut microbiome and metabolome independently of energy intake. Gut 2020;69(7):1258–1268; doi: 10.1136/gutjnl-2019-320438.
Tagliamonte S, Laiola M, Ferracane R, et al. Mediterranean diet consumption affects the endocannabinoid system in overweight and obese subjects: possible links with gut microbiome, insulin resistance and inflammation. Eur J Nutr 2021;60(7):3703–3716; doi: 10.1007/s00394-021-02538-8.
Choo JM, Murphy KJ, Wade AT, et al. Interactions between Mediterranean Diet Supplemented with Dairy Foods and the Gut Microbiota Influence Cardiovascular Health in an Australian Population. Nutrients 2023;15(16):3645; doi: 10.3390/nu15163645.
Yu J, Wu Y, Zhu Z, et al. The impact of dietary patterns on gut microbiota for the primary and secondary prevention of cardiovascular disease: a systematic review. Nutr J 2025;24(1):17; doi: 10.1186/s12937-024-01060-x.
Dierckens M, Deforche B, De Clercq B, et al. Country-level sociocultural context and socioeconomic inequalities in adolescent dietary behaviours: A multilevel analysis in 21 European countries. Appetite 2024;198:107339; doi: 10.1016/j.appet.2024.107339.
Gao P, Rinott E, Dong D, et al. Gut microbial metabolism of bile acids modifies the effect of Mediterranean diet interventions on cardiometabolic risk in a randomized controlled trial. Gut Microbes 2024;16(1); doi: 10.1080/19490976.2024.2426610.
Kimble R, Gouinguenet P, Ashor A, et al. Effects of a mediterranean diet on the gut microbiota and microbial metabolites: A systematic review of randomized controlled trials and observational studies. Crit Rev Food Sci Nutr 2023;63(27):8698–8719; doi: 10.1080/10408398.2022.2057416.
Boughanem H, Ruiz-Limón P, Pilo J, et al. Linking serum vitamin D levels with gut microbiota after 1-year lifestyle intervention with Mediterranean diet in patients with obesity and metabolic syndrome: a nested cross-sectional and prospective study. Gut Microbes 2023;15(2); doi: 10.1080/19490976.2023.2249150.
Meir AY, Rinott E, Tsaban G, et al. Effect of green-Mediterranean diet on intrahepatic fat: the DIRECT PLUS randomised controlled trial. Gut 2021;70(11):2085–2095; doi: 10.1136/gutjnl-2020-323106.
Haskey N, Estaki M, Ye J, et al. A Mediterranean Diet Pattern Improves Intestinal Inflammation Concomitant with Reshaping of the Bacteriome in Ulcerative Colitis: A Randomised Controlled Trial. J Crohns Colitis 2023;17(10):1569–1578; doi: 10.1093/ecco-jcc/jjad073.
Strauss JC, Haskey N, Ramay HR, et al. Weighted Gene Co-Expression Network Analysis Identifies a Functional Guild and Metabolite Cluster Mediating the Relationship between Mucosal Inflammation and Adherence to the Mediterranean Diet in Ulcerative Colitis. Int J Mol Sci 2023;24(8):7323; doi: 10.3390/ijms24087323.
Pagliai G, Russo E, Niccolai E, et al. Influence of a 3-month low-calorie Mediterranean diet compared to the vegetarian diet on human gut microbiota and SCFA: the CARDIVEG Study. Eur J Nutr 2020;59(5):2011–2024; doi: 10.1007/s00394-019-02050-0.
Zhou Q, Pang G, Zhang Z, et al. Association Between Gut Akkermansia and Metabolic Syndrome is Dose-Dependent and Affected by Microbial Interactions: A Cross-Sectional Study. Diabetes Metab Syndr Obes 2021;Volume 14:2177–2188; doi: 10.2147/DMSO.S311388.
Merra G, Noce A, Marrone G, et al. Influence of Mediterranean Diet on Human Gut Microbiota. Nutrients 2020;13(1):7; doi: 10.3390/nu13010007.
Jennings A, Kühn T, Bondonno NP, et al. The gut microbiome modulates associations between adherence to a Mediterranean-style diet, abdominal adiposity, and C-reactive protein in population-level analysis. Am J Clin Nutr 2024;119(1):136–144; doi: 10.1016/j.ajcnut.2023.11.001.
Vetrani C, Verde L, Colao A, et al. The Mediterranean Diet: Effects on Insulin Resistance and Secretion in Individuals with Overweight or Obesity. Nutrients 2023;15(21):4524; doi: 10.3390/nu15214524.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Cholifah Cholifah, Maulidah Ayuningtyas, Canneysha Lathiefa Zahra, Dini Ririn Andrias
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
All articles published in the Journal of Nutrition Explorations are licensed under the Creative Commons Attribution–ShareAlike License (CC BY-SA 4.0).
Under this license, users are permitted to read, download, copy, distribute, print, search, and link to the full texts of the articles, as well as adapt and build upon the material for any purpose, including commercial use, provided that appropriate credit is given to the original author(s) and the source.
Any derivative works based on the published articles must be distributed under the same Creative Commons Attribution–ShareAlike (CC BY-SA 4.0) license.
Authors who publish with the Journal of Nutrition Explorations retain the copyright of their work. By submitting and publishing their manuscripts in this journal, authors grant the journal the right of first publication.
The Journal of Nutrition Explorations supports the principles of open access, ensuring that all published articles are freely available online without subscription or access fees.
Author Rights
Authors retain the following rights:
-
The right to share and distribute their published article.
-
The right to use the article for academic and educational purposes.
-
The right to deposit the article in institutional or subject repositories.
-
The right to include the article in future books, theses, or other scholarly works.
Licensing Information
All articles are published under the Creative Commons Attribution–ShareAlike 4.0 International License (CC BY-SA 4.0).
More information about this license can be found at:
https://creativecommons.org/licenses/by-sa/4.0/
_.png){kind=small}
