Fluoride or fluorine deficiency is a disorder which may cause increased dental caries (or tooth decay, is the breakdown of dental tissues by the acidic products released by the "bacterial fermentation of dietary carbohydrates.") and possibly osteoporosis (a bone disorder which leads to a decrease in bone mass, and an increase in bone fragility), 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 seen in 1902 when fluoride in high concentrations was found to stain teeth and prevent tooth decay.
Fluoride salts, particularly sodium fluoride (NaF), 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.
Sources of fluoride
Fluorine is the 13th most aboundant element in the Earth's crust. The ionic form of fluorine is called fluoride. Fluoride is most commonly found as inorganic or organic fluorides such as naturally occurring calcium fluoride or synthetic sodium fluoride. There are a number of sources of fluoride, these include:
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.
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 (whom of which are at a greater risk of caries) in low-fluoride areas.
The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for some minerals in 1997. Where there was not sufficient information to establish EARs and RDAs, an estimate designated Adequate Intake (AI) 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 (includes pregnancy and lactation). 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 (ULs) 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 (DRIs).
The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) 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 (includes pregnancy and lactation). 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 (lower for children).
- Selwitz, Robert H (2007). "Dental Caries". The Lancet. 369 (9555): 51–9. doi:10.1016/S0140-6736(07)60031-2. PMID 17208642. Retrieved 2015-04-16.
- Kleerekoper, M. (1998). "The Role of Fluoride in the Prevention of Osteoporosis". Endocrinology and Metabolism Clinics of North America. 27 (2): 441–452. doi:10.1016/S0889-8529(05)70015-3.
- 'Vilela';'Nunes', 'Pedro'; 'Teresa' (2011). "Osteoporosis International". Neuroradiology. 53: 185–189. doi:10.1007/s00234-011-0925-4.
- "Fluorine". Merck. Retrieved 2009-01-04.
- Ilich, J. Z.; Kerstetter, J. E. (2000). "Nutrition in Bone Health Revisited: A Story Beyond Calcium". Journal of the American College of Nutrition. 19 (6): 715–737. doi:10.1080/07315724.2000.10718070. PMID 11194525.
- "Fluoride in the UK diet". 2014. Retrieved 2015-04-16.
- Gazzano, E.; Bergandi, L.; Riganti, C.; Aldieri, E.; Doublier, S.; Costamagna, C.; Bosia, A.; Ghigo, D. (2010). "Fluoride Effects: The Two Faces of Janus". Current Medicinal Chemistry. 17 (22): 2431–2441. doi:10.2174/092986710791698503.
- Olivares M, Uauy R (2004). "Essential nutrients in drinking-water (Draft)" (PDF). WHO. Archived from the original (PDF) on 2012-10-19. Retrieved 2008-12-30.
- Pizzo G, Piscopo MR, Pizzo I, Giuliana G (September 2007). "Community water fluoridation and caries prevention: a critical review". Clin Oral Investig. 11 (3): 189–93. doi:10.1007/s00784-007-0111-6. PMID 17333303.
- Aoba T, Fejerskov O (2002). "Dental fluorosis: chemistry and biology". Crit. Rev. Oral Biol. Med. 13 (2): 155–70. doi:10.1177/154411130201300206. PMID 12097358.
- "Nutritional Factors in Tooth Development". ADHA. Retrieved 2008-12-30.
- "Effect of Inorganic Fluoride on Living Organisms of Different Phylogenetic Level". 2010.
- Wood, A. J. J.; Riggs, B. L.; Melton, L. J. (1992). "The Prevention and Treatment of Osteoporosis". New England Journal of Medicine. 327 (9): 620–627. doi:10.1056/NEJM199208273270908. PMID 1640955.
- "Health Supplements and Nutritional Guides".
- Riggs, BL; Hodgson, SF; O'Fallon, WM; Chao, EY; Wahner, HW; Muhs, JM; Cedel, SL; Melton LJ, 3rd (22 March 1990). "Effect of fluoride treatment on the fracture rate in postmenopausal women with osteoporosis". The New England Journal of Medicine. 322 (12): 802–9. doi:10.1056/nejm199003223221203. PMID 2407957.
- Mamelle, N; Meunier, PJ; Dusan, R; Guillaume, M; Martin, JL; Gaucher, A; Prost, A; Zeigler, G; Netter, P (13 August 1988). "Risk-benefit ratio of sodium fluoride treatment in primary vertebral osteoporosis". Lancet. 2 (8607): 361–5. doi:10.1016/s0140-6736(88)92834-6. PMID 2899773.
- Kleerekoper, M; Peterson, EL; Nelson, DA; Phillips, E; Schork, MA; Tilley, BC; Parfitt, AM (June 1991). "A randomized trial of sodium fluoride as a treatment for postmenopausal osteoporosis". Osteoporosis International. 1 (3): 155–61. doi:10.1007/BF01625446. PMID 1790403.
- Meiers P. Fluoride Research in the 19th and early 20th century . Retrieved 2009-1-4.
- Tao S, Suttie JW (August 1976). "Evidence for a lack of an effect of dietary fluoride level on reproduction in mice". J. Nutr. 106 (8): 1115–22. doi:10.1093/jn/106.8.1115. PMID 939992.
- Gluckman, P.; Skegg, D. (2014). "Health effects of water fluoridation: A review of the scientific evidence" (PDF). Royal Society of New Zealand. Retrieved 15 April 2015.
- Institute of Medicine (1997). "Fluoride". Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride. Washington, DC: The National Academies Press. pp. 288–313.
- "Overview on Dietary Reference Values for the EU population as derived by the EFSA Panel on Dietetic Products, Nutrition and Allergies" (PDF). 2017.
- Tolerable Upper Intake Levels For Vitamins And Minerals (PDF), European Food Safety Authority, 2006