Fluorine intake of a Tibetan population

Brick tea consumption and its relationship with fluorosis in Tibetan areas

Brick tea-type fluorosis (BTF) due to a high intake of brick tea is possible in Tibetan populations, and dental fluorosis (DF) and skeletal fluorosis (SF) are its primary manifestations. To determine the prevalence of DF and SF and their relationships with brick tea intake in Tibetan populations, a literature review was conducted for studies published between 1994 and 2021. The available evidence revealed that brick tea may be produced from older stems and leaves of the tea plant and that the fluoride content of brick tea exceeds the national standard. The harsh environment of the plateau has led to limited food sources for the local Tibetan people who form the habit of drinking tea leaves as a satiation solution to digest greasy food and replenish vitamins, and regular consumption of brick tea leads to excessive exposure of Tibetan residents to fluoride. Studies in Tibet showed that the prevalence of DF in children was 14.06-75.93% in different districts, and the overall pooled prevalence of DF was 26.08%. The prevalence of SF in adults was 19.90-74.77% in different Tibetan districts, and the overall pooled prevalence of SF was 33.84%. The analysis of risk factors showed that the prevalence of BTF may be related to high-altitude and different working and living conditions, and BTF in children may be associated with fluoride intake during mothers' pregnancy and lactation. With the development of bioinformatics research, gene polymorphisms were suspected to be related to susceptibility to fluorosis in Tibetan populations. The study of BTF in Tibetan people needs to be further investigated and standardized, and additional studies evaluating the pathogenesis and preventive measures of BTF are warranted.

A Qualitative and Comprehensive Analysis of Caries Susceptibility for Dental Fluorosis Patients

Dental fluorosis (DF) is an endemic disease caused by excessive fluoride exposure during childhood. Previous studies mainly focused on the acid resistance of fluorotic enamel and failed to reach a consensus on the topic of the caries susceptibility of DF patients. In this review, we discuss the role of DF classification in assessing this susceptibility and follow the “four factors theory” in weighing the pros and cons of DF classification in terms of host factor (dental enamel and saliva), food factor, bacteria factor, and DF treatment factor. From our analysis, we find that susceptibility is possibly determined by various factors such as the extent of structural and chemical changes in fluorotic enamel, eating habits, fluoride levels in diets and in the oral cavity, changes in quantity and quality of saliva, and/or oral hygiene. Thus, a universal conclusion regarding caries susceptibility might not exist, instead depending on each individual’s situation.

The daily fluorine and arsenic intake for residents with different dietaries and fluorosis risk in coal-burning fluorosis area, Yunnan, Southwest China

The daily fluorine (F)/arsenic (As) intake (DFI/DAsI) for residents at different ages with different dietaries and dietary changes was investigated to analyze the fluorosis risk in coal-burning fluorosis area in Yunnan, Southwest China. The DFI for residents with a dietary of roasted corn and roasted chili was 5.06, 9.60, and 14.38 mg for age groups 3-7, 8-15, and over 15 years, respectively. Over 90 % of DFI was from roasted foodstuffs. The DFI for residents of the same age group living on rice and roasted chili was 1.94, 3.50, and 4.95 mg, respectively, which were less than that for the former dietary type, and 65 % of DFI was from roasted chili. The main sources for their DFI are roasted foodstuffs. Both were higher than the dietaries with non-roasted foodstuffs and the recommended daily allowances (RDAs) for USA and China at different levels. The DAsI for all residents ranged from 25 to 135 μg, and at this level of DAsI, it would not influence human health. However, As pollution of roasted foodstuffs might have an important influence for the fluorosis. Residents are changing their staple food from roasted corn to rice, and especially, younger people are more focused on quality life. However, even if residents change their staple food, the habit of eating chili will not change, which also may cause them getting fluorosis. Developing economy, changing dietary types, and changing the habit of drying and keeping chili will help to reduce the fluorosis risk in coal-burning fluorosis area of Southwest China.

Safety evaluation and fluorine concentration of Pu'er brick tea and Bianxiao brick tea

Pu'er brick tea and Bianxiao brick tea are both compressed types of tea. Fluorine analysis was carried out on samples of Pu'er brick tea produced at different times in Yunnan Province and on samples of Bianxiao brick tea made in Hunan and Sichuan Province for supply especially to minority ethnic groups in border areas of China. The levels of water-soluble and water-insoluble fluorine were measured in the tea samples using an ion-specific electrode potentiometer. The concentration of water-soluble fluorine was much greater in Bianxiao brick tea than in Pu'er brick tea (mean levels 441 and 77 mg/kg, respectively). According to these figures, the fluorine intake associated with consuming an infusion of 30 g Pu'er brick tea/person/day is safe because it does not exceed the maximum recommended daily allowance (RDA) of up to 4.0 mg for adults. In contrast, the almost six times higher intake of fluorine from Bianxiao brick tea greatly exceeds the 4 mg RDA and is unsafe. The difference in the fluorine levels of the two types of brick tea can be attributed to differences in the materials used to make them: Pu'er brick tea is made from tender leaves whereas Bianxiao brick tea is made from old tough leaves in which fluorine has accumulated. We conclude that consumption of Pu'er brick tea is unlikely to induce fluorosis, which has been associated with consumption of Bianxiao brick tea.