Too Much Coffee May Weaken Bones, Study Finds

Researchers at Flinders University in Australia followed almost 10,000 women who were 65 years old or older for ten years. They wanted to see if drinking coffee or tea could change bone mineral density (BMD), a key measure that doctors use to judge the risk of osteoporosis.

Osteoporosis is a common problem. About one in three women over 50 has it, and it causes many fractures each year around the world. Because billions of people drink coffee or tea every day, even a small effect on bone health could matter for many people.

The study used data from the Study of Osteoporotic Fractures (SOF). The researchers asked the women how much coffee and tea they drank at several points in time. They also measured BMD at the hip and the femoral neck, places that are often broken when bones are weak.

The results showed that women who drank tea had a slightly higher total hip BMD than those who did not drink tea. The difference was small, but it was statistically significant. "Even small improvements in bone density can translate into fewer fractures across large groups," says Adjunct Associate Professor Enwu Liu from the College of Medicine and Public Health.

Coffee behaved differently. Women who drank about two to three cups a day did not show any harm to their bone health. But women who drank more than five cups a day had lower BMD. This suggests that very high coffee consumption could be bad for bones.