You pour your third cup before lunch and wonder whether all that coffee is doing anything to your bones. A study of nearly 10,000 older women offers a reassuring answer for most coffee lovers, along with a caution for the heaviest drinkers.
Key Takeaways
- In women 65 and older, drinking more than five cups of coffee a day was linked to lower bone mineral density. The study, by researchers at Flinders University in Australia, was published in the journal Nutrients in December 2025.
- Two to three cups a day showed no sign of harm.
- Tea drinkers had slightly higher hip bone density than non-drinkers, though the difference was very small.
- The heavy-coffee link was strongest in women who drank more alcohol.
- This was an observational study of mostly white American women, with data gathered decades ago. It shows associations, not proof, and it didn’t measure fractures.
What the study found
The researchers analyzed data from the Study of Osteoporotic Fractures, a long-running U.S. study that enrolled 9,704 women aged 65 and older. Over about 10 years, the women reported how much coffee and tea they drank, and their bone density was measured repeatedly at the hip and the femoral neck, the narrow “neck” at the top of the thigh bone where hip fractures often happen.
Overall, coffee drinking wasn’t significantly tied to bone density. But when the researchers looked more closely at how risk changed with the amount women drank, more than five cups a day appeared to be linked to lower bone density. Moderate intake, about two to three cups a day, didn’t show any harm.
The picture was different for women who drank more alcohol over their lifetimes. In that group, higher coffee intake was more clearly linked to lower bone density at the femoral neck.
Tea drinkers came out slightly ahead. Their total hip bone density averaged 0.718 g/cm², compared with 0.715 g/cm² in non-tea drinkers. That’s statistically significant, but very small. Tea’s apparent benefit was a bit stronger in women with obesity.
Why coffee and tea might affect bones
In laboratory studies, caffeine can slightly reduce how much calcium the body absorbs and may interfere with how bone is built and broken down. The researchers point out that these effects are small and that adding milk to your coffee can help make up for it.
Tea contains plant compounds called catechins, which may support the cells that build new bone. That could explain the small edge seen in tea drinkers.
What this study can’t tell us
The researchers themselves describe the differences as modest. They say the results aren’t a reason to give up coffee or start drinking large amounts of tea. A few other limits are worth knowing:
- It’s observational. Women who drink a lot of coffee may differ in other ways, such as smoking, diet or activity, that also affect bones.
- It measured bone density, not fractures. Lower density raises fracture risk, but the study didn’t track whether the women actually broke bones.
- The data are old, and the group wasn’t diverse. The study began in the late 1980s, and nearly all participants were white. Whether the findings apply to younger women, men or other groups isn’t known.
- Intake was self-reported, and “a cup” can vary a lot from one person to the next.
What to do for your bones
Osteoporosis affects about 1 in 3 women over 50, so protecting your bones matters. Based on this study, there’s no need to give up coffee, but some simple steps help:
- Keep coffee moderate. Two to three cups a day appears to be fine. If you regularly drink five or more, consider cutting back, especially if you also drink alcohol regularly.
- Add milk. A splash of milk in your coffee or tea adds calcium.
- Cover the basics. Women over 50 need about 1,200 mg of calcium a day, from food first and supplements only if needed. Adults also need 600 to 800 IU of vitamin D a day, depending on age.
- Keep moving. Weight-bearing exercise such as walking, along with strength training, helps maintain bone, and balance exercises lower the risk of falls.
- Ask about a bone density scan. Women 65 and older should be screened for osteoporosis, and some younger women with risk factors should be screened too. Ask your doctor whether you’re due.
This isn’t a substitute for medical advice. Talk to your doctor about what’s right for you.
Sources:
- Liu RY, Liu E. 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. Nutrients, 2025;17(23):3660.
- Flinders University. Tea linked to stronger bones in older women. December 11, 2025.