A 10-year study of nearly 10,000 women aged 65 and older found that regular tea drinking was linked to slightly higher bone mineral density, a key marker of osteoporosis risk. Moderate coffee intake showed no overall harm, but consuming more than five cups a day was associated with lower bone density, particularly among women who reported higher lifetime alcohol use, according to researchers from Flinders University.
Osteoporosis, which affects about one in three women over 50 and contributes to millions of fractures worldwide each year, remains a major public health concern.
A new study led by researchers at Flinders University and published in the journal Nutrients examined how daily coffee and tea intake relate to bone mineral density (BMD) in older women.
Using data from the long-running Study of Osteoporotic Fractures, the team analysed nearly 10,000 women aged 65 and over, tracking their coffee and tea consumption and measuring BMD at the total hip and femoral neck — sites closely tied to fracture risk — over roughly a decade. Beverage intake was recorded repeatedly, and bone density was assessed using dual-energy X-ray absorptiometry and analysed with linear mixed-effects models.
The study found that women who drank tea had modestly higher total hip BMD than non-drinkers. The least-squares mean total hip BMD was 0.718 g/cm² in tea drinkers compared with 0.715 g/cm² in non-tea drinkers, a small but statistically significant difference that the authors say could matter at the population level.
“Even small improvements in bone density can translate into fewer fractures across large groups,” said Adjunct Associate Professor Enwu Liu from Flinders University's College of Medicine and Public Health, as quoted in summaries of the work.
The picture for coffee was more nuanced. Overall, the researchers reported no significant association between coffee consumption and BMD at the hip or femoral neck. Moderate coffee intake — about two to three cups daily — was not linked to changes in BMD in the main analysis. However, spline analyses suggested that consuming more than five cups of coffee per day may be associated with lower BMD. Women with higher lifetime alcohol intake appeared particularly vulnerable to coffee’s negative association with femoral neck BMD, while tea’s positive association with bone density was stronger in women with obesity.
Co-author Ryan Liu and colleagues point to catechins in tea as a likely contributor to tea’s observed benefits. These compounds may promote bone formation and help slow bone loss, according to explanations provided in institutional releases and media reports. By contrast, caffeine in coffee has been shown in laboratory studies to interfere with calcium absorption and aspects of bone metabolism, though these effects are generally small and can be offset in part by adding milk.
The Study of Osteoporotic Fractures received support from the U.S. National Institute on Aging and the National Institute of Arthritis and Musculoskeletal and Skin Diseases through several federal research grants, according to Flinders University.
Liu said the findings suggest that enjoying a cup of tea each day could be a simple way for older women to support their bone health over time. “While moderate coffee drinking appears safe, very high consumption may not be ideal, especially for women who drink alcohol,” he noted in comments released by the university and reproduced in several news reports. The authors stress that calcium and vitamin D remain central to osteoporosis prevention and that their results do not imply people should give up coffee or drink large quantities of tea, but that everyday beverage choices may play a small role in bone health.
