4. Are there any reasons for concern about people’s fluoride intake? If so, who is at risk?
The SCHER opinion states:
Exposure to fluoride occurs orally by inhalation and by dermal uptake, the former being the major route. Oral fluoride exposure is mainly by ingestion of water, water-based beverages, food (including fluoridated salt and food supplements) and swallowed dental hygiene products.
Inhalation of fluoride present in ambient air within Europe is limited and does not contribute more than 0.01 mg/day to the total intake, except in occupational settings, e.g. aluminium workers where intake can be several milligrams. Fluoride might be a component of urban and ambient air pollution, especially in coal mining and coal burning communities, but information on the level of fluoride is limited and is restricted to industrial areas. Thus, inhalation exposure of fluoride is not considered important for the general population in the EU. However in some industrial areas exposure may occur, but no systematically collected data are available.
At present, there are no reliable biomarkers to assess fluoride exposure. Fluoride in blood, nails and hair samples has not been investigated systematically with respect to their use as an exposure biomarker. Urine is commonly used to measure fluoride exposure but is unreliable because of fluctuations in urinary flow and pH which will influence fluoride output. Past fluoride exposure is also a factor that influences the urinary fluoride output due to the large fraction of fluoride accumulated in the bone that is slowly released. Measurement of plasma fluoride will only give information on recent fluoride intake.
There are no new EU data on fluoride in food. The level will to a large extent depend on the fluoride concentration naturally present in, or artificially added to, the water used for processing. In lieu of new data, EFSA considered the German background exposure to fluoride from food based on intake of milk, meat, fish, eggs, cereals, vegetables, potatoes and fruit still to be valid. The exposure corresponds to 0.042, 0.114 and 0.120 mg/day for young children, older children, and adults, respectively (EFSA 2005). Exposure to fluoride from fruit juice, soft drinks, and mineral water was considered to be 0.011 and 0.065 mg F/day for younger and older children, respectively.
The current assessment of exposure to fluoride from drinking water is based on the EFSA concise database compiling the results of consumption surveys across European countries. However, this database is only for adult exposure. The mean consumption of water-based beverages, namely tap water, bottled water, soft drinks and stimulants, i.e. coffee, tea, cocoa, ranges from about 400 mL to about 1,950 mL with a median value of 1,321 mL/day/person. These figures are consistent with the default value for water consumption (2,000 mL/day) used by WHO. The value for total consumption of liquids across European countries ranges from about 700 mL/day/person at the lowest reported mean to about 3,800 mL/day/person at the highest reported 97.5th percentile. These values show that due to human physiology and European climatic conditions, the total variability attributable to liquid consumption is close to a factor of 5. The exposure will thus mainly be driven by the level of fluoride in water for which the variability is about a factor of 30 (low fluoride levels in Germany vs. high fluoride levels in Finland).
The major sub-categories of water-based beverages are soft drinks, bottled water, stimulants, and tap water. The highest 97.5th percentiles for the consumption of a single category are 2,950, 2,400, 2,800 and 2,500 mL/day per adult respectively for tap water in Austria, stimulants in Denmark, soft drinks in Slovakia, and bottled water in Slovakia. For each of these countries, the consumption of one category at the 97.5th percentile for consumers only was summed with the mean consumption for the three other categories of water-based beverages for the whole population. Total consumption ranged from 3,300 to 3,800 mL/day/person.
Based on reported consumption of water-based beverages, several scenarios have been developed. Scenario 1 corresponds to the median of mean consumption for all water- based beverages across European countries (1,321 mL) with the mean occurrence level of fluoride (0.1 mg/L). Scenarios 2 and 3 correspond to the highest consumption for high consumers of one of the relevant categories (3,773 mL) with the mandatory water fluoridation in Ireland (0.8 mg/L) (scenario 2) and the WHO guideline value for fluoride in drinking water (1.5 mg/L) (scenario 3).
Scenario 4 is a worst-case scenario based on the highest 97.5th percentile for consumption of tap water (2,950 mL in Austria) with the upper range for fluoride concentration (3.0 mg/L in Finland).
Estimated fluoride exposure from water-based beverages for adults and children (older than 15 years of age) in the different scenarios is shown in Table 2.
Table 2: Adult and children (above 15 years of age) systemic exposure to fluoride from water-based beverages*.
|Concentration of F
*Bottled mineral water was not included in these scenarios.
Data on daily consumption of drinking water and other water-based products by children are sparse. The consumption data of drinking water and other water based products used by EFSA (2005) are from 1994 and seem to be low (under 500 mL for children less than 12 years old and under 600 mL/day for children aged between 12 and 15 years).
Fluoride content of dental hygiene products
In Annex III, part 1, of the amended Council Directive 76/768/EEC related to cosmetic products, 20 fluoride compounds are listed, that may be used in oral hygiene products. The compounds which are most commonly incorporated into toothpaste are sodium fluoride, sodium monofluoro-phosphate and stannous fluoride. Other over-the-counter oral hygiene products containing fluoride include mouthwashes, chewing gums, toothpicks, gels and dental floss.
These may contain up to a maximum of 1,500 mg F/kg (0.15% F). Toothpaste with lower fluoride content has been introduced onto the market to reduce fluoride ingestion by young children in order to minimize the risk of fluorosis. However, there is no evidence for its caries-reducing effect. Toothpaste containing a higher concentration of fluoride (more than 1,500 mg F/kg) is only available by prescription for patients with a high risk of dental caries.
It is estimated that in adults less than 10% of the toothpaste is ingested as the spitting reflex is well developed, whereas the estimated intake in children may be up to 40%. In children ingestion has been reported to be as high as 48% in 2 to 3 year olds, 42% in 4 year olds, 34 in 5 year olds, and 25% in 6 year olds. In children aged between 8 and 12 years, the ingestion is reported to be around 10% (Ellewood et al. 2008). The recommended quantity of toothpaste per application is “pea size” (about 0.25 g), whereas the application corresponding to the length of the tooth brush head is considered a worst-case situation (0.75 g).
|Type of toothpaste (% F)||Fluoride conc. (mg /kg)||Amount used* (g/day)||Total fluoride dose (mg/day)||Systemic fluoride absorption (mg) 10%||Systemic fluoride absorption (mg) 40%|
*Estimated toothpaste use with twice daily brushing.
Prescribed fluoride supplements
Prescribed fluoride supplements (tablets, lozenges, or drops) that are regulated as drugs may be recommended by qualified professionals based on a case-by-case evaluation of exposure to all other fluoride sources. As with any prescribed drug, patient compliance is a problem. It is estimated that fluoride supplements could be the source of up to 70% of the reasonable maximum dietary exposure value in infants and young children (EFSA 2005). In addition, over the counter fluoride supplement tablets, lozenges (from 0.25 to 1.0 mg) and fluoride containing chewing gums are available in some EU Member States.
Dietary supplements and fluoridated salts
Calcium fluoride can be added as a dietary supplement: 1 mg CaF2 /day would correspond to 0.5 mg F/day, but due to the low bioavailability, the anticipated absorbed daily amount is estimated to be 0.25 mg F/day (EFSA 2008a).
Sodium monofluorophosphate can be added as a dietary supplement: amounts between 0.25 and 2 mg fluoride per day have been considered to be safe (EFSA 2008b). Limits for the dietary supplements have not yet been set.
A value of 0.25 mg F/day from dietary supplements was used in the integrated fluoride exposure assessment described below because it is highly unlikely that these supplements will be used in areas with fluoridated water, or that both food supplements are used at the same time.
Many countries recommend the consumption of fluoridated salt and such products are available in at least 15 countries. The salt is fluoridated up to levels of 350 mg/kg. Figures about the proportion of fluoridated salt sold are available (Gotzfried et al. 2006).
4.2.2. Integrated exposure to fluoride from all major sources
In order to achieve an integrated fluoride exposure assessment from all sources previously discussed, water, food and toothpaste are aggregated. Since the ingested fluoride ion is readily absorbed, it is assumed that there is 100% systemic bioavailability. Medicinal supplementation is not included in these assessments.
Four scenarios were used for the current assessment of exposure to fluoride from drinking water based on the EFSA concise database, compiling the results of consumption surveys across European countries (see Table 2). However, this database is only for adult exposure.
EFSA (2005) considered the German background exposure to fluoride from food based on intake of milk, meat, fish, eggs, cereals, vegetables, potatoes and fruit still to be valid. The fluoride concentration in food may be naturally present or acquired through food processing. In addition, EFSA (2008 a, 2008b) approved the addition of calcium fluoride and sodium monofluorophosphate for nutritional purposes as a source of fluoride in food by dietary supplementation to create supplemented foods.
Oral hygiene products (mainly toothpaste) are a further variable source of fluoride depending on four variables; the fluoride concentration of the toothpaste, the quantity applied to the toothbrush, the number of times teeth are brushed daily and the amount ingested after brushing and rinsing the teeth (see Table 3). The amount ingested after brushing is critical as it then becomes systemically available.
Exposure of adults and children above 15 years of age
Estimated fluoride exposures, from Table 2 for water-based beverages for adults and children (older than 15 years of age) in the different scenarios are used, and account for 18-95% of the total fluoride intake.
The fluoride intake from food and supplemented food with dietary additives is 0.37 mg/day (0.12 mg/day food and 0.25 mg/day fluoride supplemented food; EFSA 2005, EFSA 2008a, EFSA 2008b) and accounts for less than 1-6% of the total fluoride intake.
For these scenarios, also factored is ~10% systemically available fluoride from “adult” 0.15% F toothpaste. Thus 0.075 mg F/day is systemically available from 0.5 g/day (low end) toothpaste application and 0.225 mg F/day from 1.5 g/day (high end) toothpaste application.
Table 4: The aggregated daily systemic exposure to fluoride (mg/day) for adults and children older than 15 years of age.
|F intake from water (mg/day)||Aggregated F intake (mg/day): water and food||Aggregated F intake (mg/day): water, food, toothpaste 0.075 mg F/d||Aggregated F intake (mg/day): water, food, toothpaste 0.225 mg F/d|
All calculations are rounded to 2 decimal places.
The upper tolerable intake limit (UL) for fluoride (7 mg/day) for adults and children over the age of 15 is only exceeded in areas with high levels of natural fluoride in water, whereas the UL would not be exceeded for adults and children over the age of 15 living in an area with fluoridated drinking water.
Exposure of children under 15 years old
This group is split into three age groups, children from 12-15 years old, children from 6- 12 years old and children from 1–6 years old. For all age groups, data were sparse and there was the additional factor of behavioural development.
Calculations for the exposure to fluoride are performed for four different fluoride concentrations in water ranging from 0.1 mg/L to 3.0 mg/L. Since current data on water consumption for this age group are not available, the calculations are based on three different levels of daily consumption of water: 0.5 L, 1.0 L, and 1.5 L.
It must be noted that the EFSA estimates for total fluoride exposure of children in these age groups are limited, but were used to estimate the fluoride intake from food and supplemented food with dietary additives (EFSA 2005, EFSA 2008a, EFSA 2008b).
The contribution from fluoride toothpaste is variable, depending on how well the spitting response is developed. When well developed, ~10% of the toothpaste (systemically available fluoride) is ingested and if not developed, ~40% of the toothpaste (systemically available fluoride) is ingested. The fluoride concentration of the toothpaste and the quantity of toothpaste applied to the toothbrush is critical.
Exposure of children (12-15 years of age)
Estimates of total daily systemic exposure to fluoride for children from 12-15 years old are shown in Table 5. The fluoride intake from food and supplemented food with dietary additives is estimated at 0.43 mg/day (0.114 mg/day food, 0.065 mg/day water-based beverages and 0.25 mg/day dietary supplements; EFSA 2005, EFSA 2008a, EFSA 2008b).
The contribution from toothpaste is calculated for ~10% systemically available fluoride from “adult” 0.15% F toothpaste only, since the spitting and rinsing responses are well developed. Thus 0.075 mg F/d is systemically available from 0.5 g/day (low end) toothpaste application and 0.225 mg F/d from 1.5 g/day (high end) toothpaste application.
Table 5: Aggregated total daily systemic exposure to fluoride (mg/day) for children 12 up to 15 years of age.
|Drinking water||F intake from water (mg/day)||Aggregated F intake (mg/day): water and food||Aggregated F intake (mg/day): water, food, 0.15% toothpaste|
|Low application 0.075 mg F/day||High application 0.225 mg F/day|
|0.1 mg F/L|
|Consumption 0.5 L||0.05||0.48||0.55||0.70|
|Consumption 1.0 L||0.1||0.53||0.60||0.75|
|Consumption 1.5 L||0.15||0.58||0.65||0.80|
|0.8 mg F/L|
|Consumption 0.5 L||0.4||0.83||0.90||1.00|
|Consumption 1.0 L||0.8||1.23||1.30||1.45|
|Consumption 1.5 L||1.2||1.63||1.70||1.85|
|1.5 mg F/L|
|Consumption 0.5 L||0.75||1.18||1.25||1.40|
|Consumption 1.0 L||1.5||1.93||2.00||2.15|
|Consumption 1.5 L||2.25||2.68||2.75||2.90|
|3.0 mg F/L|
|Consumption 0.5 L||1.5||1.93||2.00||2.15|
|Consumption 1.0 L||3.0||3.43||3.50||3.65|
|Consumption 1.5 L||4.5||4.93||5.00||5.15|
Fluoride and fluoridating agents of drinking water
The estimated UL for children aged between 8 and 14 years is 5 mg/day extrapolated from the UL for adults for whom the critical endpoint is an increased risk of bone fracture (EFSA 2005). This reference value was used for children aged 12-15 years despite the fact that not all molars will have erupted. The UL for children aged 12-15 years is only exceeded if 1.5 L water containing 3.0 mg F/L is consumed, and if 0.15% fluoride toothpaste and more than the recommended “pea size” application is used.
The UL could be exceeded with additional exposure from two other sources: fluoridated salt as a condiment or in food preparation and/or from the consumption of bottled mineral water with high fluoride content. Exposure of children (1-12 years of age)
The estimated total daily systemic exposure to fluoride for children between 6-12 years old and 1-6 years old is shown in Tables 6 and 7, respectively. Since current data on water consumption for children are sparse, the estimation of fluoride exposure is based upon water consumption at levels of 0.5 L, 1.0 L and 1.5 L. In warmer countries, the daily water consumption would be higher.
The intake of fluoride from food is estimated to be 0.303 mg/day. This figure is the sum from the following sources: 0.042 mg/day from food; 0.011 mg/day from water based beverages; and 0.25 mg/day from fluoridated dietary supplements(EFSA 2005, EFSA 2008a, EFSA 2008b). Due to different tooth brushing behaviours, i.e. spitting and rinsing responses, two different exposures were developed for children aged 6-12 years and 1-6 years, respectively.
For children between 6 and 12 years old the contribution from toothpaste is ~10% systemically available fluoridebecause the spitting response is well developed. Both toothpaste for adults (0.15% F) and children (0.05% F) are considered. Thus for the “adult” toothpaste, 0.075 mg F/day is systemically available from 0.5 g/day (low end) toothpaste application and 0.225 mg F/day from 1.5 g/day (high end) toothpaste application, whereas for the “children’s” toothpaste, 0.025 mg F/day is systemically available from 0.5 g/day (low end) toothpaste application and 0.075 mg F/day from 1.5 g/day (high end) toothpaste application.
Table 6: Total daily systemic exposure to fluoride (mg/day) for children 6-12 years of age.
|Drinking water||F intake from water||Aggregated F intake from water and food||Aggregated F intake: water, food, 0.05% toothpaste||Aggregated F intakwater, food, 0.15% toothpaste|
|0.025 mg F/day||0.075 mg F/day||0.225 mg F/day|
|0.1 mg F/L|
|Consumption 0.5 L||0.05||0.35||0.38||0.43||0.58|
|Consumption 1.0 L||0.1||0.40||0.43||0.48||0.63|
|Consumption 1.5 L||0.15||0.45||0.48||0.53||0.68|
|0.8 mg F/L|
|Consumption 0.5 L||0.4||0.70||0.73||0.78||0.93|
|Consumption 1.0 L||0.8||1.10||1.13||1.18||1.33|
|Consumption 1.5 L||1.2||1.50||1.53||1.58||1.73|
|1.5 mg F/L|
|Consumption 0.5 L||0.75||1.05||1.08||1.13||1.28|
|Consumption 1.0 L||1.5||1.80||1.83||1.88||2.03|
|Consumption 1.5 L||2.25||2.55||2.58||2.63||2.78|
|3.0 mg F/L|
|Consumption 0.5 L||1.5||1.80||1.83||1.88||2.03|
|Consumption 1.0 L||3.0||3.30||3.33||3.38||3.53|
|Consumption 1.5 L||4.5||4.80||4.83||4.88||5.03|
The UL for children aged between 4 and 8 years is 2.5 mg/day based on a prevalence of less than 5% of moderate dental fluorosis as the critical endpoint (EFSA 2005). This value was used as the reference value for the children aged 6-12 years. Thus the UL for children in the 6-12 years category is exceeded if 1.5 L water containing 1.5 mg F/L is consumed, independent of tooth-brushing behaviour.
The spitting response is not well developed in children aged between 1 and 6 years and ~40% systemic fluoride availability from toothpaste will be used. Toothpastes for children (0.05% F) and for adults (0.15% F) are considered. Thus, for the 0.05% F toothpaste, 0.1 mg F/day is systemically available from 0.5 g/day (low end) toothpaste application and 0.3 mg F/day from 1.5 g/day (high end) toothpaste application. For the 0.15% toothpaste, 0.3 mg F/day is systemically available from 0.5 g/day (low end) toothpaste application and 0.9 mg F/day from 1.5 g/day (high end) toothpaste application.
Table 7: Estimate of total daily systemic exposure to fluoride for children 1 up to 6 years of age.
|Drinking water||F intake from water||Aggregated F intake from water and food||Aggregated F intake: water, food, 0.05% toothpaste||Aggregated F intake: water, food, 0.15% toothpaste|
|0.10 mg F/day||0.30 mg F/day||0.90 mg F/day|
|0.1 mg F/L|
|Consumption 0.5 L||0.05||0.35||0.45||0.65||1.25|
|Consumption 1.0 L||0.1||0.40||0.50||0.70||1.305|
|Consumption 1.5 L||0.15||0.45||0.55||0.75||1.35|
|0.8 mg F/L|
|Consumption 0.5 L||0.4||0.70||0.80||1.00||1.60|
|Consumption 1.0 L||0.8||1.10||1.20||1.40||2.00|
|Consumption 1.5 L||1.2||1.50||1.60||1.80||2.40|
|1.5 mg F/L|
|Consumption 0.5 L||0.75||1.05||1.15||1.35||1.95|
|Consumption 1.0 L||1.5||1.80||1.90||2.10||2.70|
|Consumption 1.5 L||2.25||2.55||2.65||2.85||3.45|
|3.0 mg F/L|
|Consumption 0.5 L||1.5||1.80||1.90||2.10||2.70|
|Consumption 1.0 L||3.0||3.30||3.40||3.60||4.20|
|Consumption 1.5 L||4.5||4.80||4.90||5.10||5.70|
The estimated UL for children less than 5% of moderate dental fluorosis as the critical endpoint (EFSA 2005) and was used for children aged between 1-6 years. Thus, the UL is exceeded if more than 1.0 L water containing 0.8 mg F/L is consumed and tooth-brushing with the 0.15% fluoride toothpaste is included. If 1.5 L of water is consumed at this fluoride concentration, the UL is exceeded even without exposure to toothpaste.
Exposure of infants up to 12 months of age
Many infants are fully or partially breast fed during the early months of life. Fluoride intakes by fully breast-fed infants are low, but fluoride intakes by partially breast-fed infants and by formula-fed infants are different. This depends primarily on the fluoride content of the water used to prepare the infant formula products.
For infants, up to the age of 6 months, the main food source is milk, either solely breast milk or formula or a combination of both. Since the fluoride content of breast milk is low (~6 μg/L), exposure to fluoride in breast-fed infants is low (less than 0.001 mg/kg/day). Table 8 shows the wide range of fluoride intake depending on infant’s feeding pattern.
Table 8: Estimated systemic fluoride exposure of infants from formulas (simplified from Fomon and Ekstrand (1999).
|Drinking water||Infant formula||Fluoride intake mg/kg/day|
|F conc. mg/L||F conc. as fed formula mg/L*||Formula intake 170 mL/kg/day**||Formula intake 150 mL/kg/day**||Formula intake 120 mL/kg/day**|
*Assumes that 145 g of formula with a fluoride concentration of 0.7 mg/kg is diluted with 880 mL of drinking water to make 1 litre of formula.
**Mean energy intakes are approximately 114 kcal/kg/day from birth to 2 months of age and 98 kcal/kg/day from 2 to 4 months. An exclusively formula-fed infant consuming 667 kcal/L formula will therefore consume approximately 0.17 L/kg/day from birth to 2 months of age and approximately 0.15 L/kg/day from 2 to 4 months.
The fluoride concentration of the water is the main exposure source in formula-fed infants. An infant solely fed with an infant formula prepared using water containing 0.8 mg F/L ingests 0.137 mg F/kg/day compared with 0.001 mg F/kg/day for an infant who is solely breast fed. An accurate assessment of the fluoride intake of infants between 6 and 12 months old has not been addressed as such calculations would be full of assumptions, considering the variability of the different feeding patterns of infants in the EU Member States. Tolerable upper intake levels for fluoride have not been established for infants (EFSA 2005). For infants up to 6 months old, the UK DoH (1994) concluded that 0.22 mg F/kg BW/day was safe, while the US IOM (1999) derived an UL for fluoride of 0.1 mg/kg BW/day.
Fluoride in drinking water is the major source of fluoride in the general population. However, in children aged between 2 and 6 years the contribution from the use of fluoridated 1,500 mg/kg toothpaste (1.5% fluoride) can account for up to 25% of the total systemic dose. As the water fluoride concentration increases, the percentage of the daily systemic exposure from fluoride in toothpaste decreases. As a worst case scenario, the daily exposure would be less than 40% (using 0.15% F toothpaste and unsupervised application), and if application is supervised and 0.05% F toothpaste is used, the daily exposure would be less than 10% of systemic fluoride from other sources.
There are no data of sufficiently high quality on sources and levels of fluoride to perform a full uncertainty analysis within the European context. The exposure assessment is very conservative both with respect to the level of fluoride in water either naturally present or artificially added, and the consumption data are based upon 95% of the highest intake of any water-based beverage.
To pronounce itself as to whether there may be reasons for concern arising from the exposure of humans to fluoride and if so identify particular exposure scenarios that may give rise to concern in particular for any particular population subgroup.
Fluoride is not essential for human growth and development. EFSA (2005) has established upper tolerable intake levels of 1.5 and 2.5 mg fluoride/day based upon the induction of moderate dental fluorosis as the critical endpoint for effect for children aged 1-3 years and 4-8 years, respectively. The estimated UL for children between 9 and 14 years is 5 mg/day extrapolated from the adult tolerable intake level. An UL of fluoride for adults of 7 mg/day was established using increased risk of non-vertebral bone fracture as the critical endpoint (EFSA 2005).
There are no new scientific data that justify changing these values. Based upon the exposure scenarios discussed in 4.2.2 for infants, children, and adults and the intake of fluoride from water-based beverages, food, food supplement and the use of toothpaste, the UL was only exceeded in the worst case scenarios. Water-based beverages were the major fluoride sources and healthy adults and children over 15 years, consuming large quantities of drinking water (more than 3 L) and living in areas with high natural concentrations of fluoride (more than 3.0 mg/L) exceeded the UL. The contribution of fluoride from toothpaste was significant in children due to ingestion of a large proportion of the toothpaste used (40% absorption), thus for healthy children under the age of 15, the combination of high levels of fluoride in water and high water consumption would result in fluoride intakes that greatly exceed the ULs for the respective age groups. Children and adults when living in areas with fluoridated drinking water (less than 0.8 mg/L) did not exceed the UL under normal consumption and usage.
The UL for children 6-12 years old is exceeded if more than 1.0 L water containing 1.5 mg F/L is consumed and tooth-brushing with the 1.5% fluoride toothpaste is unsupervised.
For children aged between 1-6 years, the UL is exceeded if more than 1.0 L water containing 0.8 mg F/L is consumed and tooth-brushing is carried out with the 0.15% fluoride toothpaste. If 1.5 L of water is consumed at this fluoride concentration, the UL is exceeded even without exposure to toothpaste.
The UL for children between 12-15 years of age is exceeded if 1.5 L water containing 3.0 mg F/L is consumed, and if regular 1,500 mg/kg fluoride toothpaste and more than the recommended “pea size” application is used. In these older children, the spitting and rinsing response is better developed, so that ~10% of the fluoride present in toothpaste becomes systemically available.
A special concern is for groups that have a high intake of supplemented food containing fluoride, e.g. sodium monofluorophosphate, and who are living in areas where the level of fluoride in drinking water is higher than 1 mg/L. The susceptibility to develop dental fluorosis depends on the timing of the systemic exposure and the uptake of circulating fluoride by developing teeth. Other subpopulations susceptible to adverse effects of systemic fluoride exposure include the elderly, with nutritional and metabolic deficiencies as these may alter bone composition leading to skeletal fluorosis. There is no strong evidence that fluoride exposure in sub-populations with endocrine disorders (diabetes, thyroid dysfunction) have an increased risk for adverse health effects.
SCHER agrees that for adults and children over the age of 12 years the total intake of fluoride from all major sources is below the upper tolerable intake level (UL) in most parts of EU including areas with fluoridated drinking water, except for those living in areas with water naturally containing fluoride at high concentrations (above 3 mg/L) and with a high intake of water-based beverages.
SCHER concludes that for children aged between 6-12 years, the UL is not exceeded if the water consumption is less than 1.0 L/day for children living in areas with fluoridated water (below 1.5 mg/L) and using regular fluoridated toothpaste. For children between 1- 6 years old the UL is exceeded if they consume more than 0.5 L a day, and use more than the recommended quantity of regular fluoridated toothpaste.
There is no UL for infants up to 12 months of age. As shown in Table 8, when the fluoride concentration in drinking water is above 0.8 mg/L, the exposure to fluoride is estimated to exceed 0.1 mg/kg/day. This amount is 200 times higher than the amount found in breast milk.