A new study from Flinders University offers insight into how two of the world's most popular beverages, coffee and tea, may influence bone health in older women.
The research, published in the journal Nutrients, followed nearly 10,000 women aged 65 and older over a decade to explore whether their daily habits of sipping coffee or tea were linked to changes in bone mineral density (BMD), a key indicator of osteoporosis risk.
Osteoporosis is a major global health concern, affecting one in three women over 50 and contributing to millions of fractures each year. With coffee and tea consumed daily by billions worldwide, understanding their impact on bone health is critical. Until now, evidence has been mixed, and few studies have tracked these relationships over such an extended period.
The Flinders University team analysed data from the Study of Osteoporotic Fractures, using repeated measures of both beverage intake and BMD at the hip and femoral neck, areas strongly associated with fracture risk.
Over ten years, participants reported their coffee and tea consumption, while researchers measured bone density using advanced imaging techniques.
The study found that tea drinkers had a slightly higher total hip BMD compared to non-tea drinkers. While the difference was modest, it was statistically significant and could have meaningful implications at a population level.
"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, on the other hand, told a more complex story. Overall, moderate coffee consumption, about two to three cups per day, did not appear to harm bone health. However, drinking more than five cups daily was linked to lower BMD, suggesting that excessive intake may be detrimental.
Interestingly, women with higher lifetime alcohol consumption experienced more negative effects from coffee, while tea seemed particularly beneficial for women with obesity.
Ryan Liu, co-author on the paper says that compounds called catechins, abundant in tea, may promote bone formation and slow bone breakdown.
"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," says Ryan Liu from Flinders University.
Adjunct Associate Professor Enwu Liu adds that the findings suggest that enjoying a cup of tea each day could be a simple way to support bone health as we age.
"While moderate coffee drinking appears safe, very high consumption may not be ideal, especially for women who drink alcohol," he says.
The authors caution that the observed differences, while statistically significant, are not large enough to warrant dramatic changes for individuals.
"Our results don't mean you need to give up coffee or start drinking tea by the gallon," says Associate Professor Liu.
"But they do suggest that moderate tea consumption could be one simple way to support bone health, and that very high coffee intake might not be ideal, especially for women who drink alcohol.
"While calcium and vitamin D remain cornerstones of bone health, what's in your cup could play a role too. For older women, enjoying a daily cup of tea may be more than a comforting ritual, it could be a small step toward stronger bones," he concludes.
The paper, 'Longitudinal Association of Coffee and Tea Consumption with Bone Mineral Density in Older Women: A 10-Year Repeated-Measures Analysis in the Study of Osteoporotic Fractures', by Ryan Yan Liu and Enwu Liu was published in Nutrients. DOI: 10.3390/nu17233660
Acknowledgements: The funding for the SOF study comes from the National Institute on Aging (NIA) and the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), supported by grants (AG05407, AR35582, AG05394, AR35584, and AR35583).
