Fermented African Cereals as Functional Foods for Diabetes Management: A Review of Mechanisms, Biochemical Effects, and Therapeutic Potential

Abstract

Diabetes mellitus is a growing global health crisis, with over 537 million adults affected worldwide. The search for affordable, culturally relevant dietary solutions has directed attention toward traditionally fermented African cereals, particularly acha (Digitaria exilis), finger millet (Eleusine coracana), and pearl millet (Pennisetum glaucum), which are known for their rich nutritional profiles and bioactive constituents. This review examines the scientific evidence supporting the use of these three fermented African cereals as functional foods for the prevention and management of diabetes mellitus. A narrative review of the published literature was conducted. A systematic search was performed across Google Scholar, PubMed, and Scopus, yielding 284 articles after initial screening; 195 were assessed on abstract review, 112 on full-text review, and 87 were included in the final synthesis. Inclusion and exclusion criteria are detailed in the Methodology section. Sources spanned peer-reviewed studies of cereal fermentation, biochemical changes, antidiabetic mechanisms, alloxan-induced animal models, and key biochemical markers of diabetes. Fermentation significantly modifies the carbohydrate, protein, lipid, and phenolic profiles of these cereals, reducing antinutritional factors and enhancing the bioavailability of health-promoting compounds. These changes result in lower glycaemic indices, improved inhibition of digestive enzymes such as alpha-amylase and alpha-glucosidase, enhanced antioxidant activity, and beneficial modulation of gut microbiota. Evidence from in vitro and animal model studies indicates that fermented acha, finger millet, and pearl millet may improve blood glucose control, lipid profiles, liver function, and oxidative stress markers in diabetic conditions. Fermented acha, finger millet, and pearl millet show considerable promise as functional foods for diabetes management. However, the current evidence base rests almost entirely on in vitro and animal studies. The absence of human clinical trial data is the most critical limitation of the existing literature and constitutes the most urgent research priority. Incorporating these traditionally available cereals into dietary strategies could provide a low-cost, culturally appropriate complement to conventional diabetes treatment, particularly in sub-Saharan Africa, once confirmed by well-designed randomized controlled trials.