The Impact of Traditional Fermented Foods on Gut Microbiota and Digestive Health

Thesis Abstract

The increasing global interest in traditional fermented foods underscores their potential role in modulating gut microbiota and enhancing digestive health, yet limited empirical evidence exists on their specific impacts within diverse populations. This study aims to investigate the effects of regularly consuming traditional fermented foods on gut microbiome composition and digestive health indicators among adults in rural farming communities. The specific objectives are (1) to characterize the microbial diversity of selected traditional fermented foods; (2) to assess changes in gut microbiota profiles associated with fermented food intake; (3) to evaluate digestive health parameters, including incidence of gastrointestinal discomfort and stool consistency; and (4) to explore socio-cultural factors influencing fermented food consumption patterns. Employing a longitudinal mixed-methods research design, the study integrated quantitative microbiological and clinical assessments with qualitative interviews. The population comprised 200 adults aged 18–60 years from two rural districts known for traditional fermentation practices. A stratified random sampling technique was used to select participants, divided equally into an intervention group, consuming a standardized fermented food product (e.g., fermented millet or sorghum porridge) at least thrice weekly, and a control group with no regular fermented food intake over a six-month period. Data collection involved the use of high-throughput 16S rRNA gene sequencing to analyze gut microbiota from stool samples collected at baseline, three months, and six months; structured questionnaires for dietary intake and gastrointestinal health logs; and semi-structured interviews to understand cultural perceptions and barriers. Data analysis employed bioinformatics tools for microbiota profiling, including QIIME2 for alpha and beta diversity assessments and LEfSe for identifying differentially abundant taxa. Quantitative data on digestive parameters were analyzed using repeated-measures ANOVA and multivariate regression models to determine associations between fermented food consumption and health outcomes, adjusting for confounding variables such as age, sex, and socioeconomic status. The qualitative data from interviews were thematically analyzed using NVivo to elucidate socio-cultural dynamics shaping fermented food practices. It is anticipated that the findings will demonstrate significant shifts in gut microbiota composition, particularly increased abundance of beneficial taxa such as Lactobacillus and Bifidobacterium in the intervention group, accompanied by improved digestive health outcomes including reduced gastrointestinal discomfort and normalized stool patterns. These results are expected to substantiate the hypothesis that traditional fermented foods act as functional modulators of gut microbiota, thereby promoting digestive well-being. The study contributes novel insights into the microbiological and health-related effects of indigenous fermentation practices, filling existing gaps in knowledge regarding their mechanistic roles within low-resource settings. Theoretically, the research draws on the Ecological Model of Health and the Microbiome Diversity Theory, providing a framework for understanding behavioral and biological determinants of gut health. This research underscores the importance of integrating indigenous dietary practices into public health strategies targeting gastrointestinal disorders and microbiota health. It recommends promoting traditional fermentation techniques, supporting further research on specific probiotic strains, and developing culturally sensitive nutrition education programs. The findings also call for policy interventions to preserve traditional fermented food practices and foster their recognition as accessible, affordable health-promoting foods. Overall, the study emphasizes the need for multidisciplinary approaches to harness the microbiome-modulating potential of culturally rooted foods, contributing to sustainable health improvements in rural populations.