Researchers at Flinders University conducted a 10-year study of nearly 10,000 women aged 65 and older, published in Nutrients, to investigate the relationship between coffee and tea consumption and bone mineral density (BMD). The study found that moderate coffee consumption (about two to three cups per day) was not associated with adverse effects on bone health. However, women who consumed more than five cups of coffee daily exhibited lower BMD, suggesting that very high coffee intake may negatively impact bone density. In contrast, tea consumption was associated with slightly higher total hip BMD, a difference that was statistically significant, though modest.
The researchers noted that the effects of coffee and tea on bone health may be influenced by other health and lifestyle factors. For instance, women with higher lifetime alcohol consumption experienced more pronounced negative effects from coffee, while the potential benefits of tea were more evident among women with obesity. The authors suggest that compounds called catechins, abundant in tea, may promote bone formation and slow bone breakdown, whereas coffee’s caffeine content might interfere with calcium absorption and bone metabolism, effects that could be mitigated by adding milk. Despite the statistically significant findings, the researchers emphasized that the observed differences in BMD were modest and do not warrant drastic changes in individual dietary habits. They concluded that moderate tea consumption could be a simple strategy to support bone health in older women, while very high coffee intake might be less ideal, particularly for women who consume alcohol.