Effects of brewing conditions on infusible fluoride levels in tea and herbal products and probabilistic health risk assessment

Abstract

Excessive ingestion of fluorides might adversely affect the health of humans. Hence, this study aimed to investigate the concentrations of infusible fluoride in five different types of tea and herbal products; additionally, the probabilistic health risks associated with the ingestion of fluoride in drinking tea and herbal products were estimated. The highest and lowest concentrations of infusible fluoride were detected in black and white tea, respectively. On average, the highest amount of infusible fluoride was extracted following a short brewing time of 5 min in the case of black tea (2.54 mg/L), herbal tea (0.40 mg/L), and white tea (0.21 mg/L). The level of infusible fluoride during brewing was inversely associated with the leaf size of the tea and herbal products. Furthermore, the type of water used influenced the release of infusible fluoride; purified water yielded lower amounts of infused fluoride. The findings of the probabilistic health risk assessment indicated that the consumption of black tea can increase the fluoride intake leading to chronic exposure. Thus, the health risk posed by fluoride intake from drinking tea needs to be evaluated in more details in the future. Appropriate measures for health risk mitigation need to be implemented to minimize the total body burden of fluorides in humans.

The Influence of the Preparation of Tea Infusion on the Content of Fluoride and the Assessment of Health Risk for the Consumer in Poland

“…Our results indicate that increasing the brewing time from 6 to 10 min further increases the fluoride content in the infusion. These observations are consistent with the data presented in the literature [21,28,38,39,45]. Chan et al [28] examined the effect of brewing time on fluoride content in the 2, 10, and 30-min range.…”

“…To our knowledge, no studies have been published describing the exact effect of tea leaf size on fluoride content in the infusion. Pattaravisitsate et al [21] published a study showing that the average fluoride concentration in infusions prepared from fragmented tea leaves…”

“…To our knowledge, no studies have been published describing the exact effect of tea leaf size on fluoride content in the infusion. Pattaravisitsate et al [21] published a study showing that the average fluoride concentration in infusions prepared from fragmented tea leaves was higher than that of unfragmented tea leaves. In this study, significant differences in leaf size were observed in the unfragmented tea samples (average 17.7 ± 12.2 mm; range 0.6-41.1 mm), and the particle size of the fragmented tea samples was smaller, 0.4-0.6 mm.…”

“…In the remaining cases, the sources of fluoride were toothpaste and inhalation of fumes containing this element. There are many scientific reports on fluoride content in various tea infusions, simultaneously attempting to assess the health risk, mainly in countries where tea consumption is high [12,[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. Conclusions from these studies, in most cases, indicate that tea infusion is an important and insufficiently considered source of fluoride exposure, and its consumption, especially in larger quantities, may pose a potential health risk.…”