1) Fluoride is known to cause dental fluorosis, a defect of the tooth enamel caused by fluoride’s interference with developing teeth. Its visible signs are mottled or yellowed teeth. Nearly 30% of children drinking fluoridated water suffer from dental fluorosis on two or more teeth (Hileman, 1988).

2) Fluoride is associated with Alzheimer’s disease and other forms of dementia. Fluoride enters the brain and enables aluminum to cross the blood-brain barrier, resulting in increased risk for these diseases. Fluoride has also been associated with low IQ and mental retardation in children (Hileman, 1988).

3) Fluoride can cause a crippling bone disease called skeletal fluorosis. In more mild forms, symptoms of this disease include chronic joint pain, similar to the symptoms of arthritis. Arthritis has now reached near epidemic levels in the United States, and the connection to fluoridated water should be considered.

4) Fluoride depresses the activity of the human thyroid gland and has been commonly used as an effective treatment for patients with overactive thyroids. Fluoride may depress the activity of the healthy thyroid, as well, resulting in an underactive thyroid, a common cause of obesity. More than 20 million people in the United States receive treatment for thyroid problems.

5) Fluoride disrupts the activity of normally functioning hormones. Fluoride can reduce levels of melatonin, the sleep hormone, in the body, causing chronic insomnia (Hileman, 1988).