Fluoride or fluorine deficiency is a disorder which may cause increased dental caries and possibly osteoporosis, due to a lack of fluoride in the diet. Common dietary sources of fluoride include tea, grape juice, wine, raisins, some seafoods, coffee, and tap water that has been fluoridated. The extent to which the condition truly exists, and its relationship to fluoride poisoning has given rise to some controversy. Fluorine is not considered to be an essential nutrient, but the importance of fluorides for preventing tooth decay is well-recognized, although the effect is predominantly topical. Prior to 1981, the effect of fluorides was thought to be largely systemic and preeruptive, requiring ingestion. Fluoride is considered essential in the development and maintenance of teeth by the American Dental Hygienists' Association. Fluoride is also essential as it incorporates into the teeth to form and harden teeth enamels so that the teeth are more acid resistant as well as more resistant to cavity forming bacteria. Caries-inhibiting effects of fluoride were first believed to have been seen in 1902 when fluoride in high concentrations was found to stain teeth and prevent tooth decay. Fluoride salts, particularly sodium fluoride, are used in the treatment and prevention of osteoporosis. Symptoms such as fractured hips in the elderly or brittle and weak bones are caused due to fluorine deficiency in the body. Fluoride stimulates bone formation and increases bone density, however bone with excess fluoride content has an abnormal structure resulting in increased fragility. Thus fluoride therapy results in large increases in bone mineral density but the effect on fracture rates, while positive, is small. Disputes over the essentiality of fluorine date back to the 19th century, when fluorine was observed in teeth and bones. In 1973 a trial found reduced reproduction in mice fed fluorine-deficient diets, but a subsequent investigation determined that this was due to reduced iron absorption.
Role of fluoride
Fluoride has proven to be an essential element with preventative and protective properties. Fluoride is capable of combating and working against tooth decay and increases resistance to the "demineralisation of tooth enamel during attack by acidic bacterias". While essential for all individuals, it is significant for children, as when ingested, the fluoride is incorporated into their developing enamel. This in turn causes their teeth to become less prone to decay. Therefore, a relationship can be formulated, in that the more fluoride entering the body, the overall decline in the rate of decay.
Water
In Australia fluoride occurs naturally within water supplies, at a concentration of approximately 0.1 mg/L. However, this number varies amongst different populations, as specific fluoridated communities exceed this amount, ranging from 0.6-1.0 mg/L of fluoride present. The process of incorporating more fluoride into water systems is an affordable mechanism that can provide many beneficial effects in the long term.
Dentrifices
Fluoride toothpaste came into production in the 1890s, after its benefits were investigated. This product has become available to most industrialised countries, and within Australia accounts for "90% of total toothpaste purchased".
Fluoride supplements were first recognised and highly suggested by health professionals, in areas where the practice of fluoridating water was not accepted. Such mechanisms are recommended for individuals, primarily children in low-fluoride areas.
Dietary recommendations
The U.S. Institute of Medicine updated Estimated Average Requirements and Recommended Dietary Allowances for some minerals in 1997. Where there was not sufficient information to establish EARs and RDAs, an estimate designated Adequate Intake was used instead. AIs are typically matched to actual average consumption, with the assumption that there appears to be a need, and that need is met by what people consume. The current AI for women 19 years and older is 3.0 mg/day. The AI for men is 4.0 mg/day. The AI for children ages 1–18 increases from 0.7 to 3.0 mg/day. As for safety, the IOM sets Tolerable upper intake levels for vitamins and minerals when evidence is sufficient. In the case of fluoride the UL is 10 mg/day. Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes. The European Food Safety Authority refers to the collective set of information as Dietary Reference Values, with Population Reference Intake instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States. For women ages 18 and older the AI is set at 2.9 mg/day. For men the value is 3.4 mg/day. For children ages 1–17 years the AIs increase with age from 0.6 to 3.2 mg/day. These AIs are comparable to the U.S. AIs. The EFSA reviewed safety evidence and set an adult UL at 7.0 mg/day.
