A morning cup of coffee is part of many people’s daily routine, but new research suggests that very high coffee intake may be worth watching in older women. Researchers at Flinders University found different links between coffee, tea, and bone health after studying nearly 10,000 women aged 65 and older over a 10-year period.
Published in Nutrients, the study examined beverage habits and changes in bone mineral density (BMD). BMD helps doctors assess bone strength and the risk of osteoporosis. The findings do not suggest that women need to stop drinking coffee, but they raise questions about how very high coffee consumption may affect bones.
Coffee, Tea, and Bone Health
The researchers used data from the Study of Osteoporotic Fractures. Participants regularly reported how much coffee and tea they consumed. Researchers also measured bone mineral density at the hip and femoral neck, two areas strongly associated with fracture risk.
The long follow-up gave researchers an opportunity to examine whether drinking patterns were linked with changes in bone density over time. Osteoporosis remains a major concern among older adults, particularly women. About one in three women over age 50 is affected by osteoporosis, and the condition contributes to millions of fractures worldwide.
Because coffee and tea are consumed daily by billions of people, even small differences in bone health can become important when viewed across a large population.
Tea Showed a Slight Advantage
Tea drinkers had slightly higher total hip BMD than women who did not drink tea. The difference was small, although it reached statistical significance.
“Even small improvements in bone density can translate into fewer fractures across large groups,” said Adjunct Associate Professor Enwu Liu from the College of Medicine and Public Health.
The researchers point to catechins as one possible reason. These naturally occurring compounds are abundant in tea and may support bone formation while slowing the breakdown of bone tissue.
The results do not prove that tea directly prevents osteoporosis. Still, the association gives researchers another reason to study how common beverages may interact with bone health as people age.
High Coffee Intake Raised Concerns
Coffee produced a different pattern. Moderate consumption of around two to three cups per day was not associated with poorer bone health. However, women who drank more than five cups daily had lower bone mineral density.
The researchers also found that other lifestyle factors could influence the relationship. Women with higher lifetime alcohol consumption showed stronger negative associations between heavy coffee intake and bone density.
At the same time, the apparent association between tea and higher bone density was more noticeable among women with obesity.
Ryan Liu, a co-author of the study, explained that caffeine may play a role. “Coffee’s caffeine content, by contrast, has been shown in laboratory studies to interfere with calcium absorption and bone metabolism, though these effects are small and can be offset by adding milk,” said Ryan Liu from Flinders University.
What the Findings Mean
The researchers stress that the differences were modest. Statistical significance does not mean that coffee alone caused lower bone density. The study observed associations, so other factors may also have contributed.
Adjunct Associate Professor Enwu Liu said the findings suggest that regular tea consumption could be a simple way to support bone health later in life. He also noted that moderate coffee intake appears safe, while very high consumption may be less ideal, particularly among women who drink alcohol.
“Our results don’t mean you need to give up coffee or start drinking tea by the gallon,” said Associate Professor Liu.
Instead, the findings point toward moderation. Calcium and vitamin D remain important parts of maintaining healthy bones, while overall diet, physical activity, age, and other lifestyle factors also influence bone strength.
The findings suggest that very high coffee consumption may be linked to lower bone density in older women, while tea consumption was associated with slightly higher hip BMD. However, the differences were modest and do not suggest that coffee or tea alone should drive major changes in daily habits.
As Associate Professor Liu concluded, “While calcium and vitamin D remain cornerstones of bone health, what’s in your cup could play a role too.”
