A new study examining coffee and tea bone density in older women has found that tea drinkers had modestly higher hip bone mineral density than non-tea drinkers, while women consuming more than five cups of coffee a day showed lower bone density, though the researchers are careful to say the differences are small and the findings do not warrant dramatic changes to anyone’s daily habits.
The study, published in Nutrients, followed a cohort of 9,704 women aged 65 and older drawn from the Study of Osteoporotic Fractures, according to PubMed Central. Participants were tracked for 10 years, with researchers from Flinders University repeatedly assessing their coffee and tea consumption and measuring changes in bone mineral density (BMD) at the hip and femoral neck, two sites closely associated with fracture risk.
What the Coffee and Tea Bone Density Data Actually Show
The measurement method matters here. According to The Educated Patient, BMD at both sites was measured repeatedly using dual-energy X-ray absorptiometry scans, a well-established imaging technique for assessing osteoporosis risk. The repeated-measures design over a decade gives the findings more weight than a single-point snapshot would.
The tea finding is statistically significant but numerically modest. MDPI Blog reports that tea drinkers had an average hip BMD of 0.718 g/cm², compared with 0.715 g/cm² in non-tea drinkers, a difference of 0.003 g/cm². That gap is easily dismissed at the individual level. The researchers’ argument, set out by Adjunct Associate Professor Enwu Liu from the College of Medicine and Public Health, is that even small improvements in bone density can translate into fewer fractures when considered across large populations. Whether that population-level arithmetic holds in practice is a separate question the study does not resolve.
Coffee told a more complicated story. Drinking around two to three cups per day was not associated with harm. The concern emerged at the high end: women consuming more than five cups daily had lower BMD. The relationship was also modified by other factors. Women with higher lifetime alcohol consumption showed stronger negative associations with heavy coffee drinking, while the apparent tea benefit was more pronounced among women with obesity.
The Mechanistic Explanations on Offer
Ryan Liu, co-author on the paper, attributes the possible tea benefit to catechins, compounds abundant in tea, which he says may promote bone formation and slow bone breakdown. On the coffee side, Ryan Liu points to caffeine’s documented interference, in laboratory studies, with calcium absorption and bone metabolism, while noting these effects are small and can be offset by adding milk. The researchers are presenting plausible mechanisms, not proven pathways: the study is observational and cannot establish cause.
The backdrop matters. Osteoporosis is described in the paper as a major health problem worldwide, affecting roughly one in three women over age 50 and responsible for millions of fractures each year. Because vast numbers of people drink coffee or tea daily, even marginal effects on BMD are worth examining. Previous research on the question has produced mixed findings, and studies tracking participants over such an extended period have been relatively rare.
Adjunct Associate Professor Liu is explicit about the limits of what the findings justify. ‘Our results don’t mean you need to give up coffee or start drinking tea by the gallon,’ he says. ‘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.’ He adds that calcium and vitamin D remain the cornerstones of bone health, with beverage choice playing at most a supporting role.
The paper, authored by Ryan Yan Liu and Enwu Liu, is titled ‘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’ and appears in Nutrients, volume 17, issue 23. Funding for the underlying Study of Osteoporotic Fractures came from the National Institute on Aging and the National Institute of Arthritis and Musculoskeletal and Skin Diseases.
