Fluoride levels and its safety in Tea (Camellia sinensis) and Khat (Catha edulis) imported and produced in Ethiopia

Abstract

The fluoride contents of sixteen(16) different packed tea leaves (Camellia sinensis) available in Ethiopian market and ten(10) samples of Khat leaves (Catha edulis) obtained from different localities were assessed using fluoride ion selective electrode. Amounts measured varies from 33.29 to 946 μg/gm on dried weight basis (DW) with an average value of 321.27±234.1 in tea samples and 13 to 20.01 μg/gm with a mean quantity of 14.94 ±1.45 in khat Samples. Based on the common practice of drinking tea three times a day by most people which is usually prepared using six grams of tea leaves and 100 to 200 gm chewing of khat leaves for those habitual users, possible daily intake of fluoride is calculated to be 1972.62 μg and 224.1-448.2 μg from tea and khat respectively based on the average fluoride quantity data from all the samples investigated. These values alone are within acceptable range of RDA (recommended daily allowance) of 2-4 mg fluorine by World Health Organization (WHO) except in one Ethiopian brand of tea where in its possible consumption the RDA limit was surpassed. Although dental problems were commonly reported in habitual khat chewers, the fluoride content of this plant is insignificant thus the chemical principle associated with such problems might be due to other ingredient(s) than fluorine. However the contribution of these plants to the overall dietary fluoride exposure should not be undermined and attention should be given to that of high values reported in tea leaves. Therefore drinking tea in areas with high fluoride levels from water sources should be cautioned to avoid the potential acute and chronic effects of fluoride.

Key Words: Fluoride, Tea, Khat, Ethiopia, Ion selective electrode