Phytate, zinc, iron and calcium content of selected raw and prepared foods consumed in rural Sidama, Southern Ethiopia, and implications for bioavailability

Representative staple foods from Sidama, Southern Ethiopia, were analyzed for phytate using HPLC, and for Zn, Fe and Ca by flame atomic absorption spectrophotometry (AAS). Enset starchy foods had the lowest phytic acid content, followed by fermented injera prepared from tef. Oleaginous seeds (niger and sesame) had the highest phytate content (∼1600 mg/100 g). The iron content of raw tef and tef injera, unlike barley flour or corn bread, varied markedly, attributed to contaminant iron from soil. The foods prepared from enset and tef were also rich sources of calcium. Most of the fermented foods prepared from enset and tef had low Phy:Zn and Phy:Fe molar ratios, whereas corn bread (unleavened), kidney beans, sesame, and niger seeds had higher molar ratios. Absorption of intrinsic Zn, Fe, and Ca as well as any exchangeable contaminant iron is unlikely to be compromised by phytate in the fermented foods prepared from enset and tef, unless consumed together with high phytate foods such as corn bread, legumes, and oil seeds.