Does Drinking Coffee Affect Kidney Function? A Comprehensive Guide

October 31, 2025 •

3 min read

According to a 2022 study, individuals drinking two to three cups of coffee daily had a 22-23% lower risk of developing acute kidney injury. This surprising finding often leads to the question: does drinking coffee affect kidney function, and is it beneficial or harmful?

Quick Summary

This article explores the complex relationship between coffee consumption and kidney health, detailing the effects of moderate versus excessive intake, the impact on chronic kidney disease (CKD), and the role of caffeine and antioxidants.

Key Points

Moderate Intake Can Be Protective: Several studies indicate that moderate coffee consumption is associated with a lower risk of chronic kidney disease and may offer protection through its antioxidant properties.
Excessive Intake May Pose Risks: Consuming large quantities of coffee can temporarily raise blood pressure, which is a key risk factor for kidney damage, especially in those with pre-existing conditions.
Impact Varies by Individual: Factors like genetics (caffeine metabolizer status) and underlying health conditions, such as hypertension or advanced CKD, determine how coffee affects an individual's kidney function.
Additives Matter Significantly: The milk, cream, or sugar added to coffee can increase levels of potassium and phosphorus, which must be restricted in patients with advanced kidney disease.
Kidney Patients Need Caution: Individuals with CKD or on dialysis can usually have coffee in moderation, but they must count it towards their fluid allowance and consult a doctor to ensure it doesn't negatively impact their condition.

The Surprising Benefits of Moderate Coffee Consumption

For most healthy adults, enjoying coffee in moderation appears to be safe and may even offer protective benefits for kidney function. The positive effects are largely attributed to coffee's rich content of antioxidants and other bioactive compounds.

Antioxidant and Anti-inflammatory Properties: Coffee is packed with antioxidants like polyphenols and chlorogenic acids, which help combat oxidative stress and inflammation. Chronic inflammation can worsen kidney function over time, so these protective compounds may support long-term kidney health.
Improved Blood Flow: Caffeine, the most well-known component of coffee, can temporarily increase heart rate and dilate blood vessels, leading to improved blood flow. This enhanced circulation is essential for the kidneys to efficiently filter waste and maintain fluid balance.
Reduced Risk of Kidney Stones: Contrary to popular belief, several studies suggest that regular coffee and caffeine consumption can significantly lower the risk of developing kidney stones. The diuretic effect of coffee helps increase urine flow, which can flush out minerals that might otherwise form stones.
Lower Risk of Chronic Kidney Disease: Extensive research, including large cohort studies, has indicated an inverse relationship between coffee consumption and the risk of developing chronic kidney disease (CKD). Some studies show that consuming two or more cups daily is linked to an even lower risk.

Potential Risks of Excessive Intake and Considerations for Individuals with Existing Conditions

While moderate consumption has benefits, excessive coffee intake or consumption by individuals with pre-existing conditions warrants caution.

Elevated Blood Pressure: For some people, particularly those with existing hypertension, caffeine can cause a temporary increase in blood pressure. Since high blood pressure is a leading cause of kidney disease, individuals should monitor their intake and consult a healthcare provider if they have concerns.
Genetic Factors: Some individuals have a genetic variant (CYP1A2) that makes them 'slow metabolizers' of caffeine, meaning it stays in their system longer. For these individuals with high blood pressure, heavy coffee consumption could lead to complications.
Effect on Specific Kidney Conditions: For those with autosomal dominant polycystic kidney disease (PKD), early studies suggested a potential risk of cyst growth from caffeine. However, later clinical studies did not find a risk of PKD progression related to coffee consumption. Patients with existing kidney issues should always consult a nephrologist.

Coffee and Additives: What You Add Matters

It is often not the coffee itself, but the additives, that can be detrimental to kidney health, especially for those with compromised kidney function.


Feature	Black Coffee (Plain)	Coffee with Additives (e.g., Cream, Sugar)
Potassium Level	Low (approx. 116 mg per 8 oz cup)	Can be significantly higher with milk, cream, or potassium-rich additives.
Phosphorus Content	Minimal	Increases with added milk or high-phosphorus creamers.
Sugar Intake	Zero	Often high, contributing to weight gain and blood pressure issues.
Best for Kidney Patients	Safer in moderation, but should be counted towards fluid intake.	Potential to be harmful, especially for those on restricted diets for advanced CKD.

Can a Person with Chronic Kidney Disease (CKD) Drink Coffee?

For individuals with chronic kidney disease, moderation is key. The National Kidney Foundation confirms that most people with CKD can safely drink coffee, but typically recommends limiting intake to fewer than three cups a day. For those with advanced CKD or on dialysis, monitoring fluid and potassium intake is critical, and a healthcare provider's advice is necessary. Plain black coffee is generally the safest option, as additives can introduce problematic levels of potassium and phosphorus.

Conclusion: A Balanced Perspective on Coffee and Kidneys

So, does drinking coffee affect kidney function? The answer is nuanced, with evidence pointing towards potential protective effects for healthy individuals when consumed in moderation, while requiring careful management for those with pre-existing kidney conditions. The beneficial impact is likely due to its antioxidant and anti-inflammatory properties. However, the risks associated with excessive caffeine, heightened blood pressure, and additives should not be ignored. As with any dietary habit, listening to your body, understanding your individual health needs, and consulting with a healthcare professional are the best practices for incorporating coffee into a kidney-healthy lifestyle.

Frequently Asked Questions

Yes, multiple large studies suggest an inverse relationship, with moderate coffee consumption linked to a lower risk of developing CKD in healthy individuals.

Research indicates that moderate coffee and caffeine intake is associated with a reduced risk of kidney stones, not an increased one. Its diuretic effect helps increase urine flow, which can prevent stone formation.

Caffeine can cause a short-term, temporary increase in blood pressure. For people with pre-existing or poorly controlled hypertension, this can be a risk factor for worsening kidney function over time.

Most people with CKD can drink coffee in moderation, typically defined as fewer than three cups daily. However, it is essential to discuss your individual case with a healthcare provider, especially if you have advanced CKD or are on dialysis.

Both caffeinated and decaffeinated coffee contain antioxidants that may be protective. However, the caffeine in regular coffee is primarily responsible for the diuretic and blood pressure effects, so decaf may be a safer choice for those sensitive to caffeine.

Coffee contains potent antioxidants that can help reduce inflammation and oxidative stress in the kidneys. This cellular protection may contribute to a reduced risk of kidney damage and improved function over the long term.

Additives can be problematic because they often contain potassium and phosphorus, which must be restricted in individuals with compromised kidney function. Plain black coffee is the safest option.