Fluoride concentration and labeling requirements of mineral bottled water from Brazil

Introduction: Mineral waters usually contain natural fluoride (F) in their composition, but the benefits and risks of the concentrations found are not clearly informed. Objective: The aim of this study was to determine the F concentration in mineral bottled waters and to check if the concentrations found: (1) matched with those informed on the label and (2) were coherent with claims on the label about the anticaries benefits and the risks of fluorosis. Method: Two batches of twenty brands, in all forms of commercial presentation found, were analyzed. F concentration was determined in duplicate using ion-specific electrode. Labels were analyzed regarding the F concentration informed. Results: Mean F concentration was 0.08 ppm, ranging from <0.05 to 0.33 ppm. The F concentrations found were generally consistent with the concentrations informed. None of the waters analyzed presented F concentration either to have anticaries effect or fluorosis risks. However, 19 of the 20 brands evaluated highlighted on the labels that their products were “fluoridated bottled water”, suggesting that the concentrations found were “optimal” for the balance benefits/risks of F use. Conclusions: In order to avoid misleading information to the consumers, the current regulations on the composition of F in bottled water as well as their labeling should be revised.

Water is a natural resource essential for life and its quality is directly associated with good health. The consumption of bottled water has increased worldwide in recent years 1,2,3  Previous studies showed that the concentration of F in mineral bottled water varies throughout Brazil and other countries 1,3 .
In the city of São Paulo, the levels of F of 35 local brands ranged from 0.01 to 2.04 mg/l 13 . Concentrations ranging between 0.0 and 4.4 ppm F were also found among 104 brands of bottled water sold in the Brazilian market 14 . Additionally, it was shown that mineral bottled water labels did not follow Anvisa's regulations concerning the content of F; while several brands showed F concentrations above the recommended levels, and did not inform them on the labels, others showed concentrations below the required levels, although the labels still announced "contains fluoride" 14,15 .

INTRODUCTION
Although studies in different Brazilian states and cities highlighting the importance of controlling the levels of F in mineral bottled water have been performed, to the best of our knowledge no study has evaluated both F concentration and labeling of mineral bottled water sold in Maringá-PR. Therefore, the aim of this study was to determine the concentrations of   Table 1).

Evaluation of the labels
The concentrations of F informed on the labels and any other information about fluoride content were recorded for later comparison with the measured F content. Also, any mention of "fluoride mineral water" was registered.

Determination of F content
The analysis of F content was conducted with a fluoride-specific

RESULTS
All the analyzed labels informed the characteristics and composition of the water. Of the 20 brands analyzed, 19 labeled their products as "fluoridated mineral water" and informed the content of F. Only one brand, sold in gallons and bottles, did not inform the concentration of F. However, analysis showed it had 0.17 ppm F, in both containers and batches.
The actual concentrations of F were generally consistent with the concentrations informed on the labels. Table 3 shows the concentration of F informed on the label (Informed) and those measured in the analyses (Found) for each type of plastic container. The actual F content ranged from < 0.05 to 0.33 ppm F. Bearing in mind the classification for F content proposed by CECOL 7 , all specimens showed levels that neither prevent caries  In Maringá, the distribution of mineral bottled water began in the 1990s 16 , with most distributors established in the center of the city, according to data collected in 2003 16 . Over time, distribution reached more peripheral areas of the city and, nowadays, apart from the usual retailing points, the local phone directory shows mineral water distributors in several districts of the city 16 .

Consumption of mineral bottled water has been growing in Brazil
The results of the present study showed that F content in the mineral bottled water commercialized in Maringá is safe for consumption, showing no risks for dental fluorosis. In contrast, however, the concentrations found are not helpful in preventing caries either.
Similarly to the present study, previous research conducted in the Brazilian market found F content in mineral bottled water at levels that cannot prevent caries 13,14,15,17,18,19 . However, some of these stud- Mineral water is defined as water taken directly from the source, with no addition of any chemicals. Thus, no recommended F concentration for this type of water is possible. However, based on the beneficial and harmful levels of F as proposed by CECOL 7 for artificially fluoridated water, the present study found amounts of  As for the analysis of the labels, two aspects were taken into consideration in the present study: the informed F content, and the use of the term "fluoridated mineral water". As for the F content, the informed concentrations were generally in accordance with the actual measured values, different from previous studies that showed large discrepancy between informed and actual F levels 13,14,17,19 .
Such difference was frequently found for the bottled mineral water sold in Araraquara, SP (30 out of 31 brands) 17 , in São Paulo city, SP (88 out of 229 specimens) 13 , in Ponta Grossa, PR (four out of five) 19 , and for brands sold in different states of Brazil (87 out of 104) 14 .
In the present study, one out of the 20 brands of mineral bottled water did not inform the F content on the label, although the analysis revealed the presence of 0.17 ppm F. The manufacturer was contacted and reasoned that such low concentration did not need to be informed. Indeed, there is no legal requirement that obliges producers to inform F as one of the components of mineral bottled water. However, for an adequate description of the product and, hence, more control over a product that can be hazardous to oral health, uniform regulations should exist. Other researches in different countries claimed the same concern, i.e.
"water companies should consider stating their fluoride content on their labels and allow an informed decision regarding consumption of fluoridated versus nonfluoridated drinking water". 25,26,27 Despite the fact that the informed F content did not significantly differ from the measured concentrations, the present study found that most brands used the term "fluoridated mineral water" irregularly. That is, if the amount of F is not high enough to prevent caries, the term should not be used. Except for one brand, all the remaining brands showed the term "fluoridated mineral water" on their labels. Previous studies 13,14,15,28 also found disagreement between the use of this term and the actual F content in the water. In some cases, information on F content was completely absent, while in others it appeared on labels when concentrations ≥0.049 ppm were found. However, producers are required by law 11 to inform "contains fluoride" and the exact F concentration over ≥1 ppm. Discrepancies such as these have also been demonstrated in other countries 28 .
The National Department of Mineral Production (DNPM in Portuguese) is responsible for the chemical classification of mineral water. The law concerning the subject 10 establishes that mineral water should be classified according to its predominant element, and that the presence of rare elements such as iodine, arsenic, and lithium should be informed. Studies on F concentration in mineral bottled water 13,14,15,19 performed in Brazil showed that F is not a rare substance -only 18 out of the 204 brands of mineral bottled water analyzed did not present detectable amounts of F in their samples.
Thus, according to the law 10 , the term "fluoridated mineral water" should only be used if F is the predominant element in the composition. Such information could mislead consumers into believing that the product contains enough F to prevent caries.
Moreover, the DNPM reinforces the prohibition 9 by stating that neither the packaging nor the label should mention any therapeutic properties or expressions that overrate the water or cause confusion among consumers. Thus, the labels examined in the present study seem to be in conflict with the law, and consumers should be made aware of the fact.
Therefore, this information should be made available to mineral bottled water manufacturers. Furthermore, uniform regulations are required to allow supervision and control of the information of products highly consumed by the population 28 . The need to review the Brazilian regulatory standards on fluoridated products has also been highlighted for pre-and postnatal fluoridated medical supplies 29 .
Future studies to monitor the consumption, F concentration, and the information on the labels of mineral bottled water should be conducted to ensure that the population has access to high quality mineral water with adequate descriptions.

CONCLUSIONS
The mineral bottled water commercialized in the city of Maringá presents no risk of fluorosis, but does not offer protection against caries either. Reformulation of the current regulations on F content in mineral bottled waters, as well as their labeling, is required, so that mineral bottled water producers and consumers can clearly know whether the F concentration in the water offers any beneficial effect.