Bioavailability of Iron and Zinc in Fermented and Non-Fermented Cereal-Based Foods Commonly Consumed in Osun State, South West Nigeria

Iron and zinc deficiencies are among the most prevalent micronutrient deficiencies in Nigeria, particularly among women and children who rely heavily on cereal-based staple diets. Fermentation is a traditional processing technique that can significantly modify the anti-nutritional factor profile of cereals and enhance mineral bioavailability. This study compared the bioavailability of iron and zinc in fermented and non-fermented cereal-based foods commonly consumed in Osun State, South West Nigeria. An experimental design was employed using ogi, tuwo, and pap as study foods prepared by both traditional fermentation and standard non-fermented methods. Phytate, tannin, and oxalate concentrations were determined before and after fermentation. In vitro iron and zinc dialysability was used as a proxy for mineral bioavailability, employing the standard pepsin-pancreatin dialysis method. Data were analysed using paired t-tests and ANOVA. Results demonstrated that fermentation significantly reduced phytate content by 40 to 65 percent across cereal types, with corresponding increases in iron dialysability of 35 to 58 percent and zinc dialysability of 28 to 47 percent. Maize-based ogi showed the greatest fermentation-induced improvement in mineral bioavailability. Tannin reduction was more pronounced in sorghum-based preparations. The study recommends promotion of fermentation practices in community nutrition programmes targeting iron- and zinc-deficient populations in South West Nigeria. Keywords: iron bioavailability, zinc, fermentation, cereal foods, Osun State