Fluoride levels in tef [Eragrostis tef (Zucc.) Trotter] and enjera and its health implications

Abstract

The main objective of this study was to estimate the fluoride levels in tef grain and in enjera, its fermentation product in different regions of Ethiopia, especially in the regions where tef is dominantly cultivated. The effect of water used to bake the enjera was assessed by preparing fluoride-containing water in the laboratory. The daily dietary fluoride intake through enjera was assessed in Wonji Shoa by recipe questionnaires and field observations in ten households. The fluoride contents of both tef grain and enjera were higher in the Rift-Valley region of Ethiopia than in the highlands. Of the different varieties of tef, the mixed tef grain was higher (8.74 mg/kg) in its fluoride content and the brown tef grain was the least (1.89 mg/kg). Enjera from mixed tef grain baked using 10 mg/l fluoride water was found to have high (26.82 mg/kg) fluoride contents and the least (2.63 mg/kg) was for enjera processed from brown tef grain baked using tap water. Daily dietary fluoride intake was different with different fluoride concentration of the water used. In this study, the fluoride content of enjera ranges from 2.63–26.82 mg/kg and the daily-recommended human intake of fluoride ranges from 4.8-14.6 mg/kg/day. The fluoride contents of the different tef varieties vary depending on the soil type, soil ph and the type of minerals in the soil. The value of fluoride in enjera baked using tap water is safe for human consumption while enjera baked using 5 and 10 mg/l fluoride containing water may cause dental as well as skeletal fluorosis.