Does Coffee Raise Calcium Levels? The Surprising Truth

November 3, 2025 •

2 min read

According to a 2025 study in Nature, higher caffeine intake was inversely associated with osteoporosis risk, challenging long-held assumptions. But does coffee raise calcium levels in the process? While caffeine does increase urinary calcium excretion in the short term, the overall effect on blood calcium is negligible for most people, especially with adequate dietary intake.

Quick Summary

The effect of coffee on blood calcium levels is complex, but moderate consumption does not significantly raise them. Short-term caffeine intake can slightly increase calcium excretion, but the body compensates. Overall dietary intake, not just coffee, determines bone health.

Key Points

No Blood Level Increase: Coffee does not raise blood calcium levels; caffeine causes a minor, temporary increase in calcium excretion.
The Body Compensates: With sufficient dietary calcium, the body compensates for temporary excretion increases, leading to a negligible net effect.
Moderation is Safe: Moderate coffee consumption (up to 400 mg caffeine/day) is generally not linked to negative bone health for most people.
Excess is Problematic: Excessive intake, especially with a low-calcium diet, poses a higher risk for impacting bone density.
Add Milk to Offset: Adding milk to your coffee replaces minimal calcium losses from caffeine.
Nuanced Bone Health Link: Recent research suggests moderate coffee might be associated with a reduced risk of osteoporosis, possibly due to other beneficial compounds, but findings are complex.
Low Dietary Calcium is Key Factor: The most significant risk to bone health comes not from moderate coffee but from consistently low dietary calcium intake.

Understanding the Complex Relationship Between Coffee and Calcium

For years, a common misconception was that coffee significantly depletes the body's calcium, thereby harming bone health. While caffeine does increase the excretion of minerals like calcium through urine, the body effectively regulates calcium levels when dietary intake is sufficient.

The Physiological Effects of Caffeine on Calcium Metabolism

Caffeine affects calcium metabolism in several ways:

Increased Urinary Excretion: Caffeine causes a small, temporary increase in calcium loss through urine, typically only 2-4 mg per cup of coffee.
Reduced Intestinal Absorption: There may be a very slight decrease in the intestines' ability to absorb calcium from food.
Bodily Compensation: The body compensates for this minor loss by reducing calcium excretion later, maintaining calcium balance.

Moderation is Key for Bone Health

Moderate coffee intake (up to 400 mg of caffeine per day, or about 4 cups) is generally not linked to negative bone health outcomes for most healthy adults. Excessive intake, especially with a low-calcium diet, poses a higher risk.

Higher Risk Groups: Postmenopausal women and teenagers may need to be more cautious with caffeine intake.
Dietary Habits Matter: The impact of caffeine is more significant in individuals with low dietary calcium.

Can Adding Milk to Your Coffee Help?

Adding milk to coffee is a simple way to offset minor calcium losses. One cup of milk provides about 300 mg of calcium, significantly more than the small amount lost due to caffeine.

A Comparison of Coffee's Effects on Calcium


Factor	Moderate Coffee Intake (≤4 cups/day)	Excessive Coffee Intake (>4 cups/day)
Effect on Calcium Excretion	Small, temporary increase in urinary loss.	Substantial increase, especially with low dietary calcium.
Impact on Bone Density	No significant negative effect with adequate calcium.	Potential for increased bone loss, especially in at-risk groups.
Bodily Compensation	Body effectively balances minor losses.	May overwhelm compensation, leading to negative balance if not addressed.
Mitigating Factors	Easily offset by diet or adding milk.	Requires monitoring diet and possibly reducing caffeine.

Recent Research Reframes the Conversation

Recent studies present a more nuanced view. Research in Frontiers in Nutrition suggests daily coffee consumption exceeding one cup may be associated with a reduced risk of osteoporosis. This could be due to other compounds in coffee, like antioxidants. However, this area is still being researched.

Conclusion: The Final Verdict

Coffee does not raise blood calcium levels in a way that causes hypercalcemia for healthy individuals. While caffeine does increase calcium excretion slightly, the body's regulatory systems, combined with sufficient dietary calcium, prevent a meaningful impact on overall levels or bone health. Risks are mainly for those with excessive intake, existing bone issues, or inadequate calcium. Moderate consumption is generally safe and may even offer some bone density benefits. A balanced diet and lifestyle are crucial for bone health.

Sources

For more information on bone health, consult authoritative sources such as the National Institutes of Health (NIH) and the Mayo Clinic. You can also review published research in academic journals like Nature and Frontiers in Nutrition.

Frequently Asked Questions

No, moderate coffee consumption does not directly cause osteoporosis. While excessive intake with a low-calcium diet can increase bone loss, it's not a direct cause. Many studies suggest moderate intake is not a risk and may even have protective effects.

A single cup of coffee causes a very small calcium loss of approximately 2-4 mg through urine. This is negligible compared to total calcium and can be offset by adding milk.

Individuals at a higher risk of bone loss, such as postmenopausal women and those with inadequate dietary calcium, should be more mindful of caffeine consumption.

No, drinking coffee does not lead to hypercalcemia (abnormally high blood calcium levels).

The primary effect is due to caffeine, so decaffeinated coffee has minimal to no effect on calcium metabolism.

Yes, for most people, the body's homeostatic mechanisms recover. Kidneys decrease calcium excretion hours later, minimizing the net effect.

Moderate coffee consumption is not considered a risk factor for kidney stones and may even lower the risk due to increased fluid intake.

Excessive intake is generally over 400 mg per day for most adults. Higher doses can significantly increase calcium loss, especially without adequate dietary compensation.