Is Fluoride Good for Teeth and Bones?
WebMD News Archive
Oct. 10, 2000 -- Drinking bottled water may be trendy, but a new study shows that, despite its taste, the stuff straight from the tap may be better for your bones. Researchers found that drinking fluoridated tap water slightly improved bone density in women and reduced their risk of hip and spine fractures.
But the study did find an increase in wrist fractures among women who drank fluoridated water -- a fact that seriously concerns one fluoridation expert.
The study focused on more than 7,000 Midwestern women -- all at least 65 years old -- and found that "community water fluoridation slightly decreased risk of fractures at both hip and spine in older white women," says study author Kathy Phipps, PhD, an epidemiologist, bone and mineral expert, and associate professor at Oregon Health Sciences University. "This is the first comprehensive study of this issue," says Phipps, whose study was published in the British Medical Journal.
Controversy has swirled around the fluoride issue since the 1940s, when the mineral was first added to community water supplies across the U.S. as a way to prevent tooth decay. In fact, in Grand Rapids, Mich. -- the city where Phipps conducted her study -- dental decay rates declined by 56% in the 15 years after fluoride was added, she says. "Those benefits have been widely documented," she tells WebMD.
But some other studies have suggested that fluoride increases risk of bone fracture in women.
"Increased risk of fracture has been debated for a very long time," Phipps says. "And it's true that if you have very, very high doses of fluoride, you do fracture more. But at levels in community water supplies -- one part per million -- our study is showing there is no increased risk of fracture. So community water fluoridation is a safe way to prevent cavities and may be slightly beneficial for osteoporosis."
Even many types of bottled water -- with the exception of distilled water -- may contain fluoride, says Phipps: "A lot have fluoride in them; even natural spring water, even water imported from Europe, could have fluoride in it. It may have very low levels, but it has some fluoride."
For her study, Phipps recruited women who lived in four Michigan communities from 1950 to 1994. The researchers looked at each woman's household water supply to determine which women had been exposed continuously to fluoridation, those whose exposure had been mixed over the years, and those with no exposure.
All women received bone-mineral density tests (tests that are commonly used to help diagnose osteoporosis) of the spine and femur, says Phipps. Questionnaires helped establish each woman's fracture risks, asking such questions such as what drugs and supplements they took, how many children they had, whether they were in menopause, and whether they had a history of fractures. The women were also asked about their activity levels.