Total fluoride intake and urinary excretion in 4–year–old Iranian children residing in low-fluoride areas

Abstract

Knowledge of levels of fluoride ingestion and excretion is important in planning optimum fluoride therapy for young children. In previous literature, it has been assumed that only about one-third of ingested fluoride is excreted in young children. The aims of the present study were (a) to measure total fluoride intake, urinary fluoride excretion and fluoride balance, and (b) to investigate the effect of air temperature on fluoride intake and urinary fluoride excretion, in young children. Children (4 years old) living in a city, a small town and rural areas of Fars province, Iran, where drinking water contained 0·30–0·39 mg F/l, were invited to participate. Selection of subjects was by random sampling of kindergartens or health centres. The children were surveyed twice, once in summer and once in winter. Diet was obtained by 3 d diaries with interview. Samples of most foods and drinks were analysed for fluoride content. Ingestion of fluoride from toothpaste was estimated for each child. Each child's urine was collected over 24 h and analysed for fluoride content. Seventy-eight of the 116 volunteers completed all aspects of the study, which was conducted in 1995–6. For all children, the mean fluoride ingestion from diet was 0·390 (sd 0·122) mg/d or 0·028 (sd 0·008) mg/kg body weight per d. Fluoride ingestion from diet was higher in summer and higher in rural areas. The mean ingestion of fluoride from all sources was 0·426 (sd 0·126) mg/d and the mean fluoride urinary excretion was 0·339 (sd 0·100) mg/d. The difference between ingestion and urinary excretion was +0·087 (sd 0·143) mg, equivalent to 80 % excretion. Faecal excretion was not estimated. The results indicate fluoride retention at 4 years to be much lower than previously assumed.

Determination of exposure and probable ingestion of fluoride through tea, toothpaste, tobacco and pan masala

“…The amount of urinary fluoride excreted reflects the amount of fluoride ingested, and elimination of absorbed fluoride occurs mainly via kidney [23]. As reported in literature, the urinary excretion of fluoride (age group 3-6 years) is 32-80% of total fluoride intake [24][25][26]. Fluoride, in faeces, is that part which was never absorbed [27].…”

“…Fluoridated drinking water was found positively associated with cancer of oral cavity and pharynx, colon and rectum, hepato-biliary and urinary organs [39]. Human beings are protected from the adverse effect of high fluoride ingestion by the dietary habits as well as by various functions carried out by their organs, as 40-60% of fluoride ingested daily is excreted by kidneys through urine [26,40]. Calcium and magnesium form insoluble complexes with fluoride anion and multivalent cations in the small intestine and decrease the uptake of fluoride into bones and teeth significantly [40,41].…”

Fluoride in drinking water and human urine in Southern Haryana, India

“…A report from WHO [23] has reported that absorbed fluoride is excreted mainly through kidney [23]. It has been documented that the urinary excretion of fluoride (age group 3-6 years) is 32-80% of total fluoride intake [26][27][28]. The fluoride excreted in faeces, is that fraction which is not absorbed in the body [29].…”

Sources of dietary iron in urban and provincial 4‐year‐old children in Iran

“…18,19 In brief, the districts chosen were a big city (Shiraz) and a provincial town (Darab) together with its surrounding rural area. 18,19 In brief, the districts chosen were a big city (Shiraz) and a provincial town (Darab) together with its surrounding rural area.…”

“…19 In brief, validity was estimated by (i) calculating the physical activity level (PAL), and (ii) comparing the energy intakes of the children with those obtained in other studies and reference values. 19 In brief, validity was estimated by (i) calculating the physical activity level (PAL), and (ii) comparing the energy intakes of the children with those obtained in other studies and reference values.…”