Scoping Review on Traditional Fermented Cereals as Catalysts of Precision Nutrition: Mapping Evidence on Probiotic Activity, Gut Microbiota Modulation, and Human Health in Sub-Saharan Africa

Traditional fermented cereals are affordable, embedded foods that may provide viable microorganisms, fermentable substrates, and bioactive metabolites that can influence the gut microbiota and human physiology. However, evidence linking indigenous cereal fermentations in Sub-Saharan Africa (SSA) to microbiome-mediated health outcomes and precision nutrition applications remains limited. This scoping review mapped the types of traditional fermented cereal foods studied in SSA; their microbial communities and probiotic attributes; the reported effects on gut microbiota composition and function; the documented health outcomes; and the geographic gaps. The review followed the Arksey and O’Malley framework, subsequent methodological refinements, and the PRISMA-ScR reporting guideline. Searches were conducted in Scopus, PubMed, Web of Science, ScienceDirect, and Google Scholar from 2000 to mid-2026, complemented by citation searching. Eligible human, animals, and in vitro studies examined SSA-fermented cereal products and reported microbial, probiotic, gut microbiota, metabolite, or health-related outcomes. After deduplication and screening, 53 studies were included. The evidence was concentrated in SSA, particularly in cereal-based foods. Lactic acid bacteria and yeasts dominated reported fermentation communities, but strain-level validation, dose definition, and controlled human studies were uncommon. Evidence for direct gut–microbiota modulation and clinically important health effects was substantially weaker than evidence for food-level microbial diversity, in vitro probiotic properties, and improved nutrient bioaccessibility. Overall, traditional fermented cereals in sub-Saharan Africa demonstrate promising microbial, nutritional, and functional properties, but current evidence remains heterogeneous and insufficient to establish consistent effects on gut microbiota and human health. Further well-designed human studies integrating dietary, microbiome, and metabolic outcomes are needed to clarify their potential role in precision nutrition.