Study Warns: Too Much Coffee May Weaken Bones in Older Women

New research suggests that common daily beverages may have subtle but measurable effects on bone health. While moderate coffee intake appears largely neutral, tea consumption was linked to small differences in bone density that could matter over time. Credit: Stock

A decade-long study tracking nearly 10,000 older women suggests that everyday beverage choices may subtly influence bone health.

Researchers at Flinders University have investigated whether everyday drinks like coffee and tea could play a role in bone health among older women.

The study, published in the journal Nutrients, tracked almost 10,000 women aged 65 and older for ten years. The researchers examined whether regular coffee or tea consumption was associated with changes in bone mineral density (BMD), an important measure used to assess osteoporosis risk.

Osteoporosis remains a serious public health issue, affecting about one in three women over the age of 50 and leading to millions of fractures worldwide each year. Because coffee and tea are among the most widely consumed beverages globally, understanding how they may influence bone health has broad relevance. Previous research has produced inconsistent results, and long-term studies examining these links have been limited.

To address this gap, the Flinders University researchers analyzed data from the Study of Osteoporotic Fractures. Their analysis included repeated assessments of beverage intake alongside measurements of BMD at the hip and femoral neck, two regions closely linked to fracture risk.

Throughout the ten-year study period, participants regularly reported how much coffee and tea they drank. At the same time, researchers used advanced imaging methods to track changes in bone density over time.

Tea Shows a Small Benefit

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.

Possible Biological Explanations

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.

Practical Takeaways

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.

Reference: “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, 22 November 2025, Nutrients.

DOI: 10.3390/nu17233660

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).

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