Fluoride Intake from Food and Liquid in Japanese Children Living in Two Areas with Different Fluoride Concentrations in the Water Supply

Abstract

The purpose of this study was to estimate the average daily amount of fluoride from the diet ingested by Japanese children of ages susceptible to dental fluorosis in two areas with different fluoride concentrations in the water supply. Thirty-eight children aged 2–8 years participated in a survey of fluoride intake. Twenty-one out of 38 children lived in an area in which the community water fluoride concentration was an average of 0.555 ppm (moderate fluoride area: MFA), and 17 lived in a low fluoride area (LFA), which ranged between 0.040 and 0.131 ppm. To measure the fluoride intake, diets were collected with a duplicate-diet technique. The fluoride concentrations in each sample were measured using the diffusion technique of Taves and the electrode technique. Meanwhile, after clinical examinations for dental caries and fluorosis, 228 subjects aged 13–15 years were selected for analysis from the same communities. The mean DMFT in the MFA was significantly lower than that in the LFA. The severest grade of dental fluorosis observed was ‘very mild’ according to Dean’s fluorosis index in both areas. The total daily fluoride intakes were 0.0252–0.0254 mg F/kg/day in the MFA and 0.0126–0.0144 mg F/kg/day in the LFA. Differences in the fluoride concentration of drinking water in this study were reflected in the fluoride intake from the diet in a typical Japanese diet.

Fluoride Intake of Japanese Infants from Infant Milk Formula

“…The resultant powdered milk sample was reconstituted as a derived sample of 20 ml milk with one of several water F concentrations; distilled water, and 0.2, 0.6, 0.8 and 1.4 g F/ml drinking water according to those meeting the Japanese water regulations and the findings in previous reports [Tsutsui et al, 2000;Nohno et al, 2006]. The F concentration of each of the 5 derived milk samples was then measured in triplicate using an F ion selective electrode and the HMDS diffusion method as previously described.…”

Influence of Beverage and Food Consumption on Fluoride Intake in Japanese Children Aged 3–5 Years

“…We should pay attention to the Japanese culture when we look at the total fluoride intakes due to Japanese traditional green tea drinking or, in other words, changing barley tea to green tea. Nohno et al [2006] reported that the caries-preventive effect was confirmed in the moderate-fluoride area, where the average total fluoride intake from the diet was 0.0252 mg/kg/day in 2-to 5-year-old children. So in the Pacific climate zone with an annual temperature of 16 ° C, a glass of green tea (0.7 mg/l) in place of barley tea for children could bring the fluoride intake value closer to the level which, while not sufficient, is effective in caries prevention to some extent.…”

“…This is probably because the number of foods used in the market basket technique is still limited, as almost all the fluoride data in the method are mainly based on uncooked foods and the fluoride concentration of tap water for cooking is not taken into account except for boiled rice. Nohno et al [2006] found that the fluoride intake from boiled rice reflected the fluoride concentration of cooking water. Song et al [2004] reported that when water was boiling, the total amount of fluoride in the water decreased as time passed.…”

“…Nohno et al [2006] reported 24-53% in Table 1. Total fluoride intake calculated from staple food and other dishes, and beverages in 3-to 5-yearold Japanese children (n = 40 in areas with <0.08 mg F/l in water supply: 0.25 mg F/day; n = 54 in areas with 0.13 mg F/l in water supply: 0.32 mg F/day) the low-fluoride area and 42-50% in the medium-fluoride area.…”

“…When we view the two cases as groups, compared to the USA, the contribution of fast food and soft drinks to dietary fluoride intake is relatively small in Japan. In all reported cases by duplicate-diet technique [Kimura et al, 2001;Murakami et al, 2002;Nohno et al, 2006], in low-fluoride areas in Japan, the average fluoride intake from diet in children stays in the range of one fourth to one third 0.05 mg/kg/day of the US adequate level, and no child showed a value exceeding 0.10 mg/kg/ day, the tolerable upper intake level [Food and Nutrition Board Institute of Medicine, 1997]. We should pay attention to the Japanese culture when we look at the total fluoride intakes due to Japanese traditional green tea drinking or, in other words, changing barley tea to green tea.…”