Does Coffee Cause Kidney Stones? What the Science Says

If you're wondering whether your daily coffee habit might be linked to kidney stones, you're not alone. So, does coffee cause kidney stones? No. The answer may come as a surprise. Because contrary to some assumptions, coffee can actually decrease the risk of kidney stones. Research shows that moderate coffee intake can reduce the risk by 40%.

Key Points:

• Studies suggest that coffee or caffeinated beverages reduce the risk of kidney stones by 40%

• Increasing coffee intake from 1 to 1.5 cups per day may significantly lower the risk

• The protective effect may be likely due to increased urine output, reducing “supersaturation”.

• Caffeinated or decaffeinated will do but more research is necessary

• Moderation and hydration are two primary features for those with kidney stones or disease

What Are Kidney Stones and What Causes Them?

Kidney stones are hard deposits of minerals and salts that develop inside your kidneys, affecting millions on a yearly basis.

Nearly 3 million people in the US go to the doctor for kidney stones, with more than 500,000 trips to the ED (emergency department). These painful formations occur when your urine has more crystal forming molecules than the body can dilute.

The process occurs gradually—often in weeks or months.

Most kidney stones start small. But they can grow larger if the status remains favorable for crystal formation. The sizes will also vary from a size of grain to a golf ball. However, the smaller stones often pass through your urinary system without causing any acute symptoms.

What Are the Different Types of Kidney Stones?

There are four primary types of kidney stones, namely:

• Calcium oxalate stones—most common type; accounts for about 80% of all kidney stones

• Uric acid stones—more common in men; occurs when urine becomes too acidic

• Struvite stones—more common in women; often occurs as a result of infection

• Cystine stones—rare stones; often as a result of a genetic condition

Each type of kidney stone forms under different conditions in your urine. Coffee’s impact is more common in calcium oxalate stones.

What Are the Common Risk Factors for Developing Kidney Stones?

A number of factors predisposes you to developing kidney stones. Understanding these risk factors can help you better manage your condition.

• Dehydration—fluid status affects kidney stone formation; not drinking enough will lead to increased urine concentration, which makes it favorable for kidney stones to develop

• Salty diet—excess salt increases calcium in your urine

• Family history—a non-modifiable risk; genetics play a role in developing kidney stones

• Obesity—putting on extra weight increases kidney stone formation as it affects kidney function

• Underlying medical conditions—diabetes, gout, and digestive disorders increase your risk of kidney stones

Men are twice more likely to develop kidney stones than women. This is another non-modifiable risk factor that should be taken into account. Peak age of development is between 40 and 49 years old. Also, people living in the Southeastern states of the US have higher risk of kidney stone formation, hence the term “stone belt”.

How Does Coffee Impact Kidney Function and Stone Formation?

There may be several mechanisms through which coffee affects kidney function and therefore stone formation. Understanding the mechanism by which coffee can protect you from kidney stones is crucial for making informed decisions.

How Does Caffeine Affect Urine Production and Composition?

Caffeine has a hypercalciuric effect—increases calcium in the urine. But it is partially balanced out by the diuretic effect of coffee post-consumption.

As a diuretic, coffee stimulates the kidneys to produce more urine and thus increases urine flow.

Coffee also has properties that will alter the urine composition—amplifying its lower risk of stone formation. This anti-lithogenic (anti-stone formation) effect can be attributed to:

• Decrease in urinary oxalate excretion

• Increased magnesium and potassium excretion

These factors reduce the supersaturation of calcium oxalate—the key driver of stone formation.

Also, other compounds found in coffee may also contribute to its anti-lithogenic effect due to their antioxidant and anti-inflammatory properties, such as:

• Chlorogenic acid

• Trigonelline

Regular coffee consumption, as long as within moderate limits, may play a protective role against kidney stone formation. The evidence mentioned suggests beneficial changes in urine chemistry and prevention of crystal adhesion mechanisms in the kidney.

What Role Does Hydration Play in This Relationship?

Hydration plays an important role in kidney function and in reducing your risk of kidney stones. Contrary to previous assumptions, caffeine intake does not lead to dehydration in regular drinkers.

So, while it is true that caffeine has a diuretic effect, regular drinkers have reached a state of tolerance. Meaning regular drinking decreases the diuretic effect over time.

Coffee adds to your total fluid intake. It helps in maintaining the urine volume needed to prevent stone formation. The American Urological Association recommends that all stone formers should achieve a urine volume of at least 2.5 L/day. Water and other fluids with the diuretic effect of coffee achieves this.

Are There Differences Between Regular and Decaf Coffee?

No, there is no difference between regular and decaf coffee. Both of these appear to offer protection against kidney stones. A study noted that caffeinated and decaffeinated drinks offer a 10% and 9% protective effect, respectively.

Except for caffeine, decaf retains the beneficial compounds found in coffee. These include antioxidants and other bioactive compounds that could influence kidney stone formation. Nonetheless, it is important to note that most research revolves around caffeinated drinks.

How Does the Amount of Coffee Consumed Affect the Risk?

Research found out that there is a dose-response relationship between coffee and stone formation. The relationship increases with moderate consumption (up to 400 mg of caffeine) each day. This could mean about 3-5 cups of coffee.

The amount provides sufficient caffeine and fluid to promote its protective effects without risking dehydration.

Are There Specific Components in Coffee That Are Beneficial?

Yes, even though caffeine receives most of the attention, there are other components that are found to be beneficial as well.

• Polyphenols—antioxidants that may reduce the inflammation in the kidneys and urinary tract

• Chlorogenic acids—have antioxidant properties; may influence metabolism that may affect stone formation

Caffeine is the primary component found in coffee that is responsible for its protective effect against kidney stone formation. Its diuretic effect has been well-documented.

How Does This Compare to Other Fluids Like Water or Tea?

Water remains the best for kidney stone formation since it offers hydrating effects without the addition of potentially harmful compounds. But coffee and tea offer protective effects that go beyond simple fluid intake.

Are There Risks of Drinking Coffee for People with Kidney Stones?

In the general sense, drinking coffee can help in protecting against kidney stone formation. However, certain situations call for caution.

People with pre-existing kidney disease or those who consume a lot of sugar and cream in their coffee should face different considerations.

Therefore, the key to kidney health is achieving balance between your overall health status and coffee consumption. Moderation remains an important part of it, even when you are drinking beneficial beverages.

Can Coffee Worsen Existing Kidney Stones?

No, coffee cannot worsen existing kidney stones. It can even help make the stone pass easier.

The increased urine production and volume helps in flushing out small stones naturally without intervention. If you're very dehydrated or drinking coffee instead of water when you need more fluids, it might take longer for a kidney stone to pass. The goal is enough total fluid intake, with coffee as one component.

Some people worry that coffee's slight increase in calcium excretion might feed existing stones. But research doesn't support this concern. The overall protective effects outweigh any theoretical risks.

Should People with Kidney Disease Avoid Coffee?

If you’re living with advanced kidney disease, it’s a good idea to have a friendly chat with your healthcare provider about whether coffee is okay for you.

Coffee can be a comforting part of your day. But diseased kidneys might handle caffeine a bit differently compared to healthy ones, where it can actually help prevent kidney stones.

You should also keep an eye on foods with high phosphorus content. It can sneak in through coffee additives like cream or sugar. The coffee itself is usually fine, but those extras might need a second look.

Also, since caffeine can sometimes cause a temporary spike in blood pressure, and high blood pressure can be tough on kidneys, it’s worth monitoring how your body responds. Your provider can help you figure out what’s best for you.

What About Other Additives in Coffee, Like Sugar or Cream?

Coffee additives may counteract some of the kidney benefits:

• Sugar—adds calories; may contribute to obesity, which is a kidney stone risk factor; increased sugar intake can also lead to progression of kidney disease

• Cream and milk—added phosphorus; people with kidney disease should cut down; they also add calories and saturated fat

• Artificial sweeteners—generally considered safe for kidneys; though some people prefer to stay away from them if possible

• Non-dairy creamers—often contain phosphorus; may become problematic for people with kidney disease

The healthiest way to do this is to keep drinking coffee black or with less additives.

What Other Lifestyle Factors Can Help Prevent Kidney Stones?

While coffee offers protection against kidney stones, it is actually just part of a comprehensive prevention plan. There are multiple factors that can influence your stone formation risk.

Successful kidney stone prevention typically involves:

• Hydration

• Balanced diet

• Weight management

• Sometimes medication

Coffee can be an added component to this broader approach.

How Important Is Staying Hydrated?

Staying hydrated is the most important way to prevent kidney stones. You want to make enough urine to keep the stuff that forms stones diluted and moving easily through your kidneys.

Doctors usually suggest drinking enough fluids to make 2-3 liters of urine each day. This means you’ll need to drink about 3-4 liters of fluids, depending on how active you are and the weather where you live.

Water is the best choice for staying hydrated. Drinks like coffee or tea can help a little, but water is the purest option and doesn’t have anything that could cause problems.

Check your urine color to see if you’re drinking enough. If it’s pale yellow, you’re doing great. If it’s dark yellow, you need to drink more fluids.

What Dietary Changes Can Reduce Kidney Stone Risk?

Here are some simple diet changes to lower your risk of kidney stones:

• Cut back on salt—eating too much salt makes more calcium show up in your urine, which can lead to kidney stones.

• Eat less meat—too much meat, like beef or chicken, can raise uric acid and lower citrate in your urine, which makes stones more likely. Stick to about 6-8 ounces of meat per day.

• Watch out for high-oxalate foods if you’re at risk for calcium oxalate stones—foods like spinach, beets, nuts, and chocolate have a lot of oxalates, which can cause stones. You don’t have to totally avoid these healthy foods, though, for most people.

• Eat more citrus fruits—fruits like oranges and lemons have citric acid, which helps prevent stones by sticking to calcium and boosting citrate levels in your urine.

Are There Medications or Supplements That Can Help?

Yes, there are. But usually these are reserved for people who keep having stones—”recurrent stone formers.”

• Thiazide diuretics—not a supplement; medications prescribed with caution as it also leaves you with mineral deficit. It reduces calcium excretion.

• Citrate supplements—potassium citrate or sodium citrate increases citrate levels in the urine; helps in preventing stone formation

• Allopurinol—medication prescribed for gout; it reduces uric acid production

• Specific dietary requirements—some people benefit from magnesium or vitamin B6 supplements; though these supplements should only be taken under supervision

Any medication or supplement you are taking should be discussed with your doctor. Your provider can assess stone formation based on your risk factors or family history.

If you think you ve the risk factors for stone formation, monitor your urine using at-home urine strips.

For further reading, check these articles:

What is Atrophic Kidney? When the Body Filters Begin to Fail

What Is a Kidney Cleanse and Is It Necessary?

Quick Summary Box

Coffee consumption can reduce your kidney stone risk by up to 40% when you drink 1-2 cups daily. The protective effect comes from caffeine's ability to increase urine production, which dilutes stone-forming minerals and helps flush them from your kidneys. Both regular and decaf coffee offer benefits, though regular coffee shows stronger effects. Research involving over 500,000 people confirms that coffee drinkers have significantly lower rates of kidney stone formation compared to non-coffee drinkers. This protection works best as part of an overall healthy lifestyle that includes staying well-hydrated with water and following a balanced diet.

Frequently Asked Questions

How can I tell if I have a kidney stone?

You can tell by the symptoms. Symptoms include severe pain in the side/back, blood in urine, nausea, frequent urination. But these symptoms do not automatically mean they are caused by kidney stones, you should always consult your doctor.

Can I still drink coffee if I’ve had kidney stones before?

Yes, you can. However, it must be in moderation and ensure that you’re getting enough fluids.

How much water should I drink to prevent kidney stones?

You should aim for 2–3 liters of fluid daily. This should be adjusted for climate or your activity.

References

Barghouthy, Y., Corrales, M., Doizi, S., Somani, B. K., & Traxer, O. (2020). Tea and coffee consumption and pathophysiology related to kidney stone formation: a systematic review. World Journal of Urology, 39(7), 2417–2426. https://doi.org/10.1007/s00345-020-03466-8 

Cleveland Clinic. (2016). Uric Acid Stones. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/16378-uric-acid-stones

Finkielstein, V. A., & Goldfarb, D. S. (2006). Strategies for preventing calcium oxalate stones. CMAJ, 174(10), 1407–1409. https://doi.org/10.1503/cmaj.051517 

Harvard Health Publishing. (2012). Kidney stones: Common, painful, preventable - Harvard Health. Harvard Health; Harvard Health. https://www.health.harvard.edu/diseases-and-conditions/kidney-stones-common-painful-preventable 

Karki, N., & Leslie, S. W. (2022). Struvite And Triple Phosphate Renal Calculi. PubMed; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK568783/ 

Kidney Stones: Medical Mangement Guideline - American Urological Association. (2019). Www.auanet.org. https://www.auanet.org/guidelines-and-quality/guidelines/kidney-stones-medical-mangement-guideline 

Leslie, S. W., Sajjad, H., & Murphy, P. B. (2024). Renal calculi, nephrolithiasis. Nih.gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK442014/ 

Maughan, R. J., & Griffin, J. (2003). Caffeine ingestion and fluid balance: a review. Journal of Human Nutrition and Dietetics, 16(6), 411–420. https://doi.org/10.1046/j.1365-277x.2003.00477.x

National Kidney Foundation. (2024, August 13). Phosphorus and Your Diet. National Kidney Foundation. https://www.kidney.org/kidney-topics/phosphorus-and-your-diet 

Peerapen, P., & Thongboonkerd, V. (2018). Caffeine in Kidney Stone Disease: Risk or Benefit? Advances in Nutrition, 9(4), 419–424. https://doi.org/10.1093/advances/nmy016 

Romero, V., Haluk Akpinar, & Assimos, D. G. (2024). Kidney Stones: A Global Picture of Prevalence, Incidence, and Associated Risk Factors. Reviews in Urology, 12(2-3), e86. https://pmc.ncbi.nlm.nih.gov/articles/PMC2931286/ 

Servaas, E., Grelewicz, O., Juśkiewicz, A., Haber, M., Czachor, A., Kotula, A., Kula, P., Kucy, N., & Siemiątkowski, R. (2024). Does drinking coffee reduce the risk of kidney stone formation? Quality in Sport, 29, 55585. https://doi.org/10.12775/qs.2024.29.55585 

Stamatelou, K., & Goldfarb, D. S. (2023). Epidemiology of Kidney Stones. Healthcare, 11(3), 424. https://doi.org/10.3390/healthcare11030424 

Wang, S., Zhang, Y., Mao, Z., He, X., Zhang, Q., & Zhang, D. (2014). A Meta-Analysis of Coffee Intake and Risk of Urolithiasis. Urologia Internationalis, 93(2), 220–228. https://doi.org/10.1159/000356559 

Yuan, S., & Larsson, S. C. (2021). Coffee and Caffeine Consumption and Risk of Kidney Stones: A Mendelian Randomization Study. American Journal of Kidney Diseases, 79(1). https://doi.org/10.1053/j.ajkd.2021.04.018