**2. Effects of fluoride in the body (fluorosis)**

Many assumption states that consuming fluoride only pose risk on dental health [10]. However, fluoride affects many tissues in the body besides the teeth [3]. Fluoride has been reported to be an endocrine disruptor that can affect the bones, brain, thyroid gland, pineal gland and blood sugar levels. The ability of fluoride to cause brain damage constitutes one of the most active areas of fluoride research and many studies have demonstrated that fluoride is a neurotoxin (a chemical that can damage the brain) [11]. Studies have demonstrated association of fluoride toxicity with varieties of health problems including increased lead absorption, disruption of collagen synthesis and muscle disorders, hyperactivity and/or lethargy, thyroid disease and lowered thyroid function, arthritis, bone fractures and bone cancer (osteosarcoma), dementia, genetic damage and cell death, increased cancer rate, disruption of the immune system and inhibition of antibodies formation and damage of sperms and increased infertility [3, 11–13].

Most developed countries do not fluoridate their water and countries that fluoridated their water do not have less tooth decay than countries that do not fluoridate their water [3]. Based on the few data available on fluoride in drinking water, there is an established relationship between dental caries and environmental fluoride in drinking water [14]. Although with decline in the water supply systems in most parts of Nigeria due to increasing human population demand, about 90% of people use groundwater (well and borehole) for drinking and other domestic purposes [15]. About 40% of American teenagers show visible signs of fluoride overexposure. In infants, fluoridated water provides no benefits but only risks. However, swallowing fluoride tablets provides little benefit to the teeth [14].
