At a time when the UK government is pressing to have the public water system fluoridated, 900 doctors, dentists and environmentalists in the USA are urging Congress to stop water fluoridation until its safety has been established.
The group cites new scientific evidence that suggests fluoridation has serious health risks. "Fluoride can harm bones, teeth, kidneys, the brain and more," says lawyer Paul Beeber, president of the New York State Coalition Opposed to Fluoridation.
Fluoride in the water supply, even at the supposedly 'safe' levels, can also affect the thyroid gland. America's National Research Council says that people who are iodine deficient are especially vulnerable, it says in its first ever report into the safety of fluoridated water.
"A low level of thyroid hormone can increase the risk of cardiac disease, high cholesterol, depression, and, in pregnant women, decreased intelligence of offspring," says the NRC's Kathleen Thiessen, co-author of the report.
Robert Carton, an environmental scientist who worked for 30 years for the US government, says: "Fluoride has detrimental effects on the thyroid gland of healthy males at 3.5 mg a day. With iodine deficiency, the effect levels drop to 0.7 milligrams a day for the average male."
The amount of fluoride in most water supplies is 1 mg per lire.
Despite these health concerns, the UK government is pressing local water authorities to start introducing fluoride into the public supply.
(Source: Townsend Letter, February 2008, 26).