Researchers at Flinders University have found new evidence that coffee and tea may have different relationships with bone health in older women.
Published in Nutrients, the study tracked nearly 10,000 women aged 65 and older for 10 years. The researchers examined whether regular coffee and tea consumption was associated with changes in bone mineral density (BMD), an important measure used to assess osteoporosis risk.
Osteoporosis is a major health problem worldwide. It affects roughly one in three women over age 50 and is responsible for millions of fractures each year. Because billions of people drink coffee or tea every day, even small effects on bone health could have broad implications. Previous research on the subject has produced mixed findings, and relatively few studies have followed participants for such a long period.
Tracking Coffee, Tea, and Bone Density
The Flinders University researchers used data from the Study of Osteoporotic Fractures. They repeatedly assessed participants’ beverage habits and measured BMD at both the hip and femoral neck, two areas closely linked to fracture risk.
During the 10-year study period, the women regularly reported how much coffee and tea they drank. Researchers also used advanced imaging methods to monitor changes in their bone density.
The results showed that women who drank tea had slightly higher total hip BMD than those who did not drink tea. The difference was small, but it was statistically significant and could still matter when considered across large populations.
“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.
Heavy Coffee Intake Linked to Lower Bone Density
Coffee showed a more complicated pattern. Drinking moderate amounts, about two to three cups per day, was not associated with harm to bone health. However, women who drank more than five cups a day had lower BMD, suggesting that very high coffee consumption could have negative effects.
The relationship also appeared to differ depending on other health and lifestyle factors. Women with higher lifetime alcohol consumption experienced stronger negative effects associated with coffee, while the apparent benefits of tea were more pronounced among 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.
A Possible Benefit From Daily Tea
Adjunct Associate Professor Enwu Liu adds that the findings suggest that regularly drinking tea could offer a simple way to support bone health later in life.
“While moderate coffee drinking appears safe, very high consumption may not be ideal, especially for women who drink alcohol,” he says.
The researchers emphasize that the differences they observed were modest. Although the findings were statistically significant, they were not large enough to justify major changes in an individual’s daily habits.
“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.
Acknowledgments: 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).
