Fermented millet products across the globe: a bibliometric and systematic narrative review of potential health impact

Millets are “Nutri cereals” loaded with minerals, vitamin B, dietary fibre, non-starchy poly-carbohydrates, proteins, antioxidants, essential fatty acids, and phytochemicals. Millet intake offers health benefits, including the prevention of heart disease, obesity, type 2 diabetes, hyperlipidemia, and hyperglycemia. However, to fully exploit their potential, processing is necessary. Fermentation is one of the cost-effective and widely used processing methods in fermented millet products. This review aims to identify fermented millet products globally with potential health impacts, along with a bibliometric analysis and a systematic narrative study. The bibliometric analysis was conducted using databases collected from Scopus and Dimension AI, while the systematic narrative study was conducted using databases such as Scopus, PubMed, and Dimension AI, following the PRISMA guidelines. Other parts of this review also included non-systematic studies supporting the health-promoting effects of millet, including its nutritional profile, the type of fermentation and its effects (such as biomodification and microbial diversity), pre-clinical/in-vivo studies elucidating the mechanisms underlying its health benefits. The bibliometric analysis revealed the publication numbers per year and the top publishing countries. The number of publications was found to be highest in 2024, which may be attributed to the declaration of the International Year of Millets in 2023 by the United Nations. India and China were found to have the largest number of publications, with a count of 107 and 88, respectively. Scientific narrative study revealed that most of the studies conducted on fermented millets are either based on pre-clinical or in-vivo studies, and only scanty information is present on human studies, which could be the potential future research areas. Another deficit identified in the analysis was the non-randomized animal trials, which need attention in future research.