A study by researchers at Flinders University has found that drinking more than five cups of coffee a day may be linked to lower bone mineral density in older, postmenopausal women, while tea drinking was associated with stronger bone density. The findings, published in the journal Nutrients, matter because osteoporosis is a major global health concern, particularly for women, who are more prone to bone loss after menopause, and who make up a large share of the ageing population most at risk of fractures.

The research tracked coffee and tea habits among 9,704 women aged 65 and over across a decade, measuring bone density at the hip and femoral neck. Moderate coffee intake of two to three cups daily showed no negative effect, but heavy consumption, especially combined with higher alcohol intake, was linked to weaker bones, whereas tea's benefits were more pronounced in women with obesity. Researchers suggested tea's catechin compounds may support bone formation, while caffeine can hinder calcium absorption, though this effect is minor and can be reduced by adding milk. They stressed the results do not mean women must give up coffee, but that moderate tea drinking could help support bone health.