Fluoride and Your Bones: A Mixed Bag

Most experts recommend drinking fluoridated water to help prevent tooth decay, but questions still remain about fluoride's role in bone health.

Fluoride in Drinking Water

Many communities in the United States add fluoride to their drinking water to prevent tooth decay. Some scientists have raised concerns about fluoridation's relationship with osteoporosis, a disease that gradually weakens the bones and increases the chance of fractures. According to the American Academy of Orthopaedic Surgeons, 28 million Americans, mostly women, suffer from the potentially painful, debilitating disease.

The Paradox of Fluoride and Bone Density

Fluoride has been shown to increase the number of cells that build bone. From the 1950s through the 1980s, sodium fluoride was often suggested as a treatment for osteoporosis. But in the 1980s, Mayo Clinic researchers discovered, during controlled trials involving postmenopausal women, that fluoride increased bone mineral density but also increased the incidence of fractures, especially in the lower extremities.

Some scientists continue to study fluoride as a possible treatment, but studies have shown that, at high, therapeutic doses, the agent upsets the gastrointestinal system and is not consistently absorbed.

"The thinking is that the bone quality formed under the influence of fluoride is not normal. It gets incorporated in the crystal and changes the crystal's structure and stimulates production of a different kind of bone," says Dr. Cosman, clinical director of the National Osteoporosis Foundation. "Fluoride may impair the mineralization of bone. Bone quality may be abnormal even though bone mass goes up."

Fluoride in Water vs. Straight Fluoride

Robert R. Recker, MD, coordinator of the Osteoporosis Research Center at Creighton University in Omaha, Nebraska, cautions that fluoride given as a treatment differs from water fluoridation.

"The Mayo Clinic treatment trials are not pertinent to water fluoridation," says Dr. Recker. "Fluoridation in the water is not a risk. And fluoride as a treatment may still pan out. It hasn't been given an adequate trial with the proper formulation."