Scientists studied tea, coffee, and bone health for 10 years - one drink came out ahead

Ryan Yan Liu and Adjunct Associate Professor Enwu Liu of Flinders University tracked nearly 10,000 women aged 65 and older across ten years to ask what habitual coffee and tea drinking was doing to their skeletons - and the drink that came out ahead for bone mineral density wasn’t the one most Western women reach for at breakfast.

The findings, published in the journal Nutrients, add a measurable, decade-long signal to the conversation around tea and bone health - a topic that carries real clinical weight. According to the NIH, osteoporosis affects about one in five women over age 50 and contributes to millions of fractures each year, many involving the hip, where fractures are associated with serious disability and loss of independence.

The Study Behind the Finding

Liu and Liu drew data from the Study of Osteoporotic Fractures, a prospective cohort of 9,704 women aged 65 and older. Coffee and tea intake were repeatedly assessed via self-administered questionnaires at multiple visits spanning approximately ten years, while femoral neck and total hip bone mineral density (BMD) were measured using dual-energy X-ray absorptiometry - a low-radiation scan that gives precise readings of bone density at specific sites.

The femoral neck - the narrow section connecting the ball of the hip joint to the thigh bone - and the total hip are areas strongly associated with fracture risk in older women. Most nutrition research on beverages and bone health has relied on single-point measurements, which cannot capture how habits and bone density shift together over time. Tracking the same women repeatedly across a decade gives a more reliable picture of what habitual drinking patterns actually do to skeletal structure.

Tea and Bone Health: What the Data Show

Tea drinkers showed slightly but significantly higher BMD at the total hip compared to non-tea drinkers. At a population scale, even a modest shift in average BMD represents a meaningful reduction in fractures, hospitalizations, and deaths.

Tea consumption appeared particularly beneficial for women with obesity - a subgroup finding the study’s repeated-measures design was built to detect. Obesity in older women is independently associated with changes in bone metabolism, and the stronger tea signal in this group suggests the mechanism may interact with metabolic factors.

Catechins - a class of plant-based antioxidants concentrated in green and black tea - are the most plausible driver of the advantage. These compounds may promote bone formation and slow bone breakdown by exerting estrogen-like activity, enhancing osteoblast activity, and suppressing osteoclast-mediated bone resorption. Osteoblasts build bone; osteoclasts break it down. Tea appears to tip that balance in the building direction.

A 2025 meta-analysis published in Frontiers in Nutrition found that green tea catechins such as EGCG (epigallocatechin gallate) appear to improve both osteoblast and osteoclast activity, suggesting tea consumption may support bone health through multiple mechanisms. This is preliminary evidence from observational and laboratory research; long-term randomized trials are needed to confirm the effect.

What Coffee Actually Does to Bone

Moderate coffee consumption of approximately two to three cups per day did not appear to harm bone health in the Flinders study - a meaningful reassurance for the majority of coffee drinkers whose daily habit sits in that range. Consuming more than five cups of coffee per day may be associated with lower bone mineral density, the study found.

Coffee consumption was also negatively associated with femoral neck BMD in women with higher lifetime alcohol intake. High coffee intake combined with regular alcohol consumption may compound each other’s impact on femoral neck density - the bone site most associated with serious fracture risk in older women.

Caffeine is the most plausible mechanism. Caffeine has been shown to interfere with calcium absorption - the mineral that is the primary building material of bone tissue. At high enough doses over time, reduced absorption creates a deficit the body compensates for by drawing calcium from bone itself. Two to three cups of coffee fall within the range the study found to be benign; the risk concentrates at very high intake and appears amplified by alcohol.

Why Bone Density Matters

As mentioned, osteoporosis affects about 18.8% of women aged 50 and over in the United States, with rates rising sharply after 65. Bone density declines quietly across menopause and the decade that follows, without symptoms, until a fall that would barely bruise a younger person causes a fracture that changes the course of someone’s life.

The National Institute on Aging lists adequate calcium intake and vitamin D as part of osteoporosis prevention. The Flinders findings add a reason to consider habitual beverage choices - something most people never include in a bone health conversation - as carrying a measurable, decade-long signal.

Because participants were not randomized - researchers observed what people chose to drink rather than assigning specific beverages - it is possible that tea drinkers shared other habits that also protect bones. Researchers accounted for many confounding factors, but no observational study can fully rule out that possibility. The biological mechanism via catechins makes the relationship biologically plausible; confirming it definitively would require a long-term randomized trial.

The Alcohol Interaction

Coffee consumption was negatively associated with femoral neck BMD, specifically in women with higher lifetime alcohol intake. Alcohol independently disrupts bone remodeling by suppressing osteoblasts and reducing calcium absorption. When high coffee intake adds caffeine’s calcium-interference effect on top of alcohol’s effects, the combined impact on femoral neck density appears more pronounced than either factor alone.

For women who regularly combine high coffee intake - five or more cups daily - with regular alcohol consumption, this study points to a specific reason to reconsider one or both habits. The evidence supports moderate consumption of both; the combination at high levels is not neutral for bones.

Replacing a fifth or sixth cup of coffee with a cup of green or black tea preserves the ritual of a warm beverage, delivers caffeine at lower concentrations, and adds catechins that appear to support the bone-building side of the equation. For heavy coffee drinkers who also drink alcohol regularly, that substitution carries the clearest potential benefit from the study’s data.

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What to Do With This

One to three cups of coffee daily falls within what this decade-long study found to be safe for bone density. Five or more cups is where the data suggest pulling back - particularly if alcohol is also a regular part of your week.

Adding tea - specifically green or black varieties, which carry the highest concentrations of bone-supporting catechins - does not need to replace coffee entirely. Even one or two cups of tea daily alongside a moderate coffee habit adds catechin exposure associated with the BMD benefit the study found. Women in the obesity subgroup had the strongest tea-associated signal and may have the most to gain.

Calcium and vitamin D remain important pillars of bone health - no amount of tea substitutes for adequate calcium intake or sufficient vitamin D. Tea appears to add a supporting role, not a replacement for established prevention strategies.

Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis, or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.

AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.

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