Observational study finds tea consumption associated with higher bone density in older women — Evidence Review
Published in Nutrients, by researchers from Flinders University
Researched by
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Table of Contents
A decade-long study suggests that daily tea consumption may offer modest benefits for bone mineral density in older women, while very high coffee intake could be linked to lower bone strength. These findings from Flinders University align with most prior research, which generally finds small positive effects of tea and limited or dose-dependent risks from coffee for bone health.
- Multiple observational studies have reported that tea drinking is associated with higher bone mineral density (BMD) and may help preserve hip structure in older women, supporting the new study’s findings, though the magnitude of benefit is consistently small 1 2 3 4 5.
- Research on coffee and caffeine has yielded mixed results, but moderate intake does not appear harmful in most studies; higher consumption may accelerate bone loss, particularly in women with low calcium intake or certain genetic factors 6 8 9.
- Systematic reviews indicate that moderate caffeine intake (up to 400 mg/day) is not associated with adverse bone health effects in healthy adults, but populations with low calcium intake or additional risk factors may be more susceptible 7 9.
Study Overview and Key Findings
Osteoporosis is a significant health concern for aging women, with one in three women over 50 affected and millions of fractures occurring globally each year. Since coffee and tea are daily staples for much of the world’s population, understanding their long-term impact on bone health is an important public health question. The Flinders University study stands out for its large sample size and extended follow-up, monitoring nearly 10,000 women aged 65 and older for ten years to assess how regular coffee and tea consumption might influence bone mineral density (BMD), a key marker for osteoporosis risk, at the hip and femoral neck—areas most vulnerable to fracture.
| Property | Value |
|---|---|
| Organization | Flinders University |
| Journal Name | Nutrients |
| Authors | Enwu Liu, Ryan Liu |
| Population | Women aged 65 and older |
| Sample Size | n=10,000 |
| Methods | Observational Study |
| Outcome | Bone mineral density (BMD) |
| Results | Tea drinkers had higher hip BMD than non-drinkers. |
Literature Review: Related Studies
To provide context for these findings, we searched the Consensus database (over 200 million papers) for relevant research using the following queries:
- tea bone density older women
- coffee hip bone mineral density
- caffeine effects bone health comparison
Below is a summary of key topics emerging from related studies and their main findings:
| Topic | Key Findings |
|---|---|
| Does tea consumption benefit bone mineral density in older women? | - Tea drinkers generally have higher BMD and may experience less bone loss than non-drinkers, although the effects are modest 1 2 3 4 5. - Flavonoids and catechins in tea are hypothesized to contribute to bone health 1 5. |
| What is the impact of coffee and caffeine intake on bone health? | - High caffeine or coffee intake may accelerate bone loss, especially in women with low calcium intake or certain genetic factors 6 8. - Moderate coffee/caffeine intake (up to ~400 mg/day) is not associated with adverse effects in most adults 7 9. |
| How do lifestyle factors and dietary patterns interact with bone health? | - Physical activity and alcohol can influence BMD, with green tea and moderate alcohol associated with increased BMD in some studies 4. - Adequate calcium intake may offset potential negative effects of caffeine on bone 8 9. |
| Do increased bone density changes translate into lower fracture risk? | - While tea is linked to higher BMD, most studies find its effect on actual fracture risk is small or not statistically significant 3. - Preservation of hip structure from tea intake may contribute to reduced fracture risk, but evidence is limited 2. |
Does tea consumption benefit bone mineral density in older women?
Multiple studies consistently report that tea drinking is associated with higher bone mineral density in older women, though the effect size is generally modest. The new Flinders University study confirms this trend, noting a statistically significant but small increase in hip BMD among tea drinkers. These findings align with previous research suggesting that bioactive compounds in tea, such as flavonoids and catechins, may play a protective role in bone metabolism.
- Tea drinkers have higher BMD at multiple skeletal sites compared to non-drinkers, independently of factors like age, BMI, and hormone therapy use 1 2.
- Longitudinal data suggest tea consumption is associated with less bone loss at the hip over time 2.
- The positive effect of tea on bone density does not necessarily result in a large reduction in actual fracture risk 3.
- Green tea and its bioactive components may support bone formation and reduce bone resorption 4 5.
What is the impact of coffee and caffeine intake on bone health?
Evidence regarding coffee and caffeine is more mixed. While moderate intake appears safe for bone health in most healthy adults, higher levels of caffeine or coffee are linked to increased bone loss, particularly in women with low calcium intake or specific genetic backgrounds. The new study’s finding that consuming more than five cups of coffee per day is associated with lower BMD is consistent with this literature.
- High caffeine intake (>300 mg/day) accelerates bone loss at the spine, especially in genetically susceptible individuals 6.
- Women with low calcium intake who consume high caffeine may have greater bone loss than those with adequate calcium 8.
- The small negative effect of caffeine on calcium absorption can be offset by adding milk or maintaining adequate calcium intake 9.
- Systematic reviews show that up to 400 mg caffeine/day is generally not harmful to bone status in healthy adults 7.
How do lifestyle factors and dietary patterns interact with bone health?
Lifestyle and dietary factors modulate the impact of both tea and coffee on bone health. Studies indicate that physical activity, green tea consumption, and moderate alcohol intake are associated with increased BMD, while factors like smoking or low calcium intake can heighten risk. The new study’s observation that alcohol intake may amplify coffee’s negative effects and that tea’s benefits are more pronounced in women with obesity is consistent with these findings.
- Physical activity and green tea drinking are each linked to higher BMD after adjusting for confounders 4.
- Alcohol consumption may have a complex relationship with bone health, with some studies suggesting moderate intake is beneficial, while others highlight potential risks 4.
- Adequate calcium intake is central to mitigating any potential negative effects from caffeine or coffee 8 9.
- Individual dietary patterns, including dairy intake and nutrient status, likely influence the impact of beverage choices on bone health 9.
Do increased bone density changes translate into lower fracture risk?
Although increased BMD is a positive outcome, the translation of these changes into reduced fracture risk is less clear. Most studies, including large cohort analyses, find that while tea consumption may slightly increase BMD, it does not significantly reduce fracture incidence among postmenopausal women. The Flinders University study’s emphasis on population-level impact reflects this nuanced relationship.
- Habitual tea drinking is associated with small increases in BMD but little to no reduction in fracture risk 3.
- Preservation of hip structure through tea intake may help reduce fracture risk, but direct evidence is limited and effects are modest 2.
- The clinical significance of small BMD changes from beverage consumption remains a topic for further investigation 1 2 3.
- Large-scale, long-term studies with fracture outcomes are needed to clarify these relationships 3.
Future Research Questions
Understanding the relationship between commonly consumed beverages and bone health in older women raises several new research questions. Further studies are needed to clarify underlying mechanisms, explore effects in diverse populations, and determine whether observed changes in BMD meaningfully reduce fracture risk.
| Research Question | Relevance |
|---|---|
| Does increased tea consumption reduce fracture risk in older women? | While tea is linked to higher BMD, it remains unclear if this translates into fewer fractures, which is a critical clinical outcome 2 3. |
| How do coffee and caffeine affect bone health in populations with low calcium intake? | Some studies indicate higher risk of bone loss with high caffeine intake in women with suboptimal calcium, but more data are needed to assess this interaction across diverse dietary patterns 8 9. |
| What are the mechanisms by which tea and coffee influence bone metabolism? | The bioactive compounds in tea and coffee, such as flavonoids, catechins, and caffeine, may act through different pathways; understanding these could inform personalized dietary recommendations 1 5 10. |
| Are the effects of tea and coffee on bone health modified by genetics or other lifestyle factors? | Genetic factors (e.g., vitamin D receptor polymorphisms) and lifestyle habits (alcohol, physical activity) may alter susceptibility to beverage effects, warranting deeper investigation 4 6. |
| What is the impact of different types of tea (green, black, oolong) on bone health in older adults? | Most studies do not differentiate between tea types; understanding potential differences could help optimize dietary guidance for bone health in aging populations 4 5. |