Fluorides, commonly known by the collective term fluoride, are compounds containing fluorine, the most reactive element found on the periodic table. Fluoride can help prevent tooth decay and cavities, and promotes strong teeth and enamel. Tooth decay and poor tooth health are, thus, signs of fluoride deficiency, and long-term deficiency can lead to osteoporosis. Consuming excessive fluoride can create chalky white, irregular patches on the surface of teeth, causing the enamel to appear mottled. In very large amounts, fluoride is toxic and can cause gastrointestinal symptoms and sometimes even death. Signs of fluoride overdose include excessive salivation, tremors, weakness, convulsion and a soapy or salty taste in the mouth. In addition, high amounts of fluoride over several years can cause brittle bones, but this is extremely rare. The RDA is 0.01 mg/day for 0-6 months infants, 0.5mg/day for 7-12 months infants, 0.7 mg/day for 1-3 years children, 1 mg/day for 4-8 years, 2 mg/day for 9-13 years children, 3 for adolescents aged between 14 and 18 years, 4 mg/day for adults, 3 mg/ day for pregnant women and 3 mg/day for breastfeeding women.