Does Coffee Hurt Your Kidneys? A Dietitian Explains What the Research Says

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If you enjoy starting your morning with a warm cup of coffee, you’re not alone. But if you’re living with chronic kidney disease (CKD), you may wonder, “does coffee hurt your kidneys?“

As a renal dietitian, I hear this question often. The good news is that, for most people, coffee can be part of a kidney-friendly diet when enjoyed in moderation. In fact, growing research suggests coffee may even offer some health benefits, including possible protection against kidney disease, diabetes, and heart disease.

Still, there are important details to know before you pour your next cup. In this article, we’ll review what the science says about coffee, caffeine, and kidney health, including potential risks, smart swaps, and how to make your daily brew as kidney-friendly as possible.

Coffee Nutrition Facts

While a cup of plain, black coffee provides no carbohydrates, fats, or protein, it does provide other nutrients. An 8-oz cup of black coffee provides;

• 8 ounces of fluid
• ~95 milligrams of caffeine
• ~124 milligrams of potassium

Antioxidants in Coffee

Coffee is known to be a good source of antioxidants. Antioxidants help protect the body from free radicals and keep our cells healthy.

The antioxidants primarily found in coffee are polyphenols, like chlorogenic acid.

How Much Caffeine Per Day is Safe?

Up to 400 milligrams of caffeine per day appears safe for most healthy adults.

Over 500 milligrams of caffeine per day can result in anxiety, constipation, diarrhea, and rapid heart rate.

Caffeine Comparison Chart

Below is a table of different sources of caffeine.

Beverage / Product	Typical Serving Size	Approximate Caffeine (mg)
Brewed Coffee (black)	8 oz	95 mg
Espresso	1 oz (single shot)	65 mg
Instant Coffee	6 oz	50 mg
Decaf Brewed Coffee	8 oz	<5 mg
Black Tea	6 oz	35 mg
Green Tea	8 oz	30 mg
Matcha (powdered green tea)	8 oz	40—70 mg
Cola	12 oz can	35 mg
Energy Drink	8 oz	70–100 mg
Pre-Workout Drink	8 oz	200–400 mg
Dark Chocolate	1 oz	20 mg
Milk Chocolate	1 oz	6 mg
Chocolate-Covered Espresso Beans	1 oz	230 mg

Coffee Kidney Benefits

There are actually several benefits to including coffee in a kidney-friendly diet.

Next, we will review what the most recent research has to say about if drinking coffee is okay for kidney disease.

Reduced Risk of Developing Kidney Disease

Drinking coffee may prevent chronic kidney disease (CKD) in those that do not have CKD.

A 2020 review found a significant decrease in risk of CKD development in coffee drinkers compared to non-coffee-drinkers.

More recently, an analysis published in 2025 found that higher coffee consumption was linked to lower risk of developing kidney disease.

Slower Kidney Disease Decline

Another study published in 2024 looked at over 78,000 people with kidney disease and coffee consumption.

They found that those that drank coffee had a slower decline with a 3% lower risk of kidney function decline than those who did not drink coffee.

Hypertension

You may have heard myths that coffee increases blood pressure, otherwise known as hypertension.

Interestingly enough, there has been a “U-shaped” risk curve with caffeine and hypertension.

Those who drank less than one cup of coffee per week or more than three cups of coffee per day were found to have lower risk for developing hypertension.

Coffee may have a short-term effect that raises blood pressure.

However, the research does not show long-term hypertension risks with drinking coffee.

Cardiovascular disease

Cardiovascular disease is the number one cause of death for people with chronic kidney disease.

Evidence has shown that 3-5 cups of coffee per day is associated with a 15% reduced risk of cardiovascular disease.

Furthermore, drinking at the higher range of acceptable caffeine limits has not been associated with an increased risk of developing cardiovascular disease.

Type 2 Diabetes

A review published in 2025 found that each additional cup of coffee (without added sugar or sweeteners) was associated with a 10% lower risk of developing type 2 diabetes.

Metabolic Syndrome & Other Health Conditions

A study published in 2024 found that drinking 3 or more cups of coffee per day decreased the risk for metabolic syndrome.

Metabolic syndrome is a term for a collection of risk factors that increase risk for health conditions including heart disease and stroke.

A person may be diagnosed with metabolic syndrome if they have at least three of the five following conditions:

• Large waist circumference
• High blood pressure
• High blood sugars
• High blood triglycerides
• Low HDL cholesterol

There are also studies that show regular coffee-drinkers have lower risks for developing liver cirrhosis, cancer, as well as Alzheimer’s and Parkinson’s diseases.

Is Coffee Bad for Kidney Stones?

Many with kidney stones are concerned about the impact coffee may have on kidney stone formation.

Coffee is commonly thought to cause dehydration, due to its diuretic effect.

However, a meta-analysis published 2022 found that a higher intake of caffeinated beverages, including coffee, lowers the risk of kidney stones.

A large cohort study published in 2022 found that drinking 50% more coffee was associated with a 40% lower risk of kidney stones. Furthermore, an increase of 80 milligrams of caffeine was associated with a 19% lower risk of kidney stones.

A review published in 2021 looked over 13 studies related to both coffee and tea with the risk of kidney stones.

They found that moderate coffee consumption did not increase the risk for kidney stones, “provided the recommended daily fluid intake is maintained.”

This is important because people who are at risk for kidney stones must drink 2-3+ liters of fluid per day, including coffee.

However, a paper published in 2020 reported caffeine increasing the risk of kidney stones for women and people of color with a history of kidney stones.

Overall, the research supports coffee and caffeine in prevention of kidney stones.

Read more about kidney stones here.

Mushroom Coffee Safe for Kidney Disease?

Mushroom coffee has gained popularity in recent years as a “healthier” alternative to traditional coffee.

It’s typically made by blending regular coffee with powdered medicinal mushrooms such as reishi, lion’s mane, cordyceps, or chaga.

These mushrooms are dried, ground, and combined with instant coffee to create a beverage that’s lower in caffeine and rich in antioxidants.

Caffeine Content

Most mushroom coffee blends contain about half the caffeine of regular coffee; usually around 40–50 milligrams per 8-ounce cup.

Potential Benefits

Some mushrooms used in these blends are thought to have anti-inflammatory and antioxidant properties. For example:

• Reishi may support immune health and reduce fatigue.
• Lion’s mane has been linked to improved cognitive function.
• Cordyceps may support energy metabolism.
• Chaga contains high levels of polyphenols and melanin, contributing to antioxidant activity.

While these benefits sound promising, it’s important to note that most research on medicinal mushrooms is preliminary and often conducted in animals or small human trials.

No studies have specifically examined the effects of mushroom coffee on kidney disease.

What Kidney Patients Should Watch For

Even though mushroom coffee can be a lower-caffeine alternative, it’s not automatically kidney-safe. Consider the following:

Potassium Content

Some mushrooms, especially chaga and reishi, are naturally high in potassium.

When concentrated into powder form, this can further increase potassium amounts per serving.

This can be something to be mindful of if you are on a potassium-restricted diet.

Herbal Additives

Many mushroom coffee products include added herbs, sweeteners, or “adaptogenic” ingredients (like ashwagandha or maca).

These can interact with medications or add extra phosphorus or potassium. They can be especially dangerous for people with a kidney transplant.

Lack of Regulation

Supplements and functional foods like mushroom coffee aren’t regulated in the same way as prescription medications.

Quality, purity, and dosage can vary significantly between brands.

The Bottom Line

As a renal dietitian, I remain cautious about recommending mushroom coffee. There’s currently no evidence showing it offers any additional benefits for kidney health compared to regular coffee. And because research is still limited, we don’t yet know whether mushroom coffee could pose risks for people with chronic kidney disease.

There’s no need to switch if you tolerate regular coffee and enjoy it in moderation.

A balanced diet and evidence-based choices will always do more for your kidneys than unproven alternatives.

If you still would like to try it, please consult with your nephrologist or renal dietitian prior to starting.

How Could Coffee Hurt Your Kidneys?

While the research shows benefits for coffee with kidney disease and/or kidney stones, is it still possible that coffee could cause kidney damage?

In some situations, yes.

Fluid Restriction

Fluids can still add up, no matter what type of fluid it is. Coffee will be a part of your fluid goals, even if you are on a medically-ordered fluid restriction.

A few extra-large cups can easily take you above your daily fluid needs, especially with kidney disease.

Here are some serving size examples:

• A ‘tall’ is 12 ounces (1 1/2 cups)
• A ‘grande’ is 16 ounces (2 cups)
• A ‘venti’ is 24 ounces (3 cups)
• A ‘trenta’ is 30 ounces (3 3/4 cups)

In some cases, a fluid restriction of 1 liter per day (4 cups) could be almost totally used up with one ‘trenta’ coffee. Be sure to include any coffee as a part of your daily fluid intake.

Excessive Caffeine

As mentioned, coffee has a short-term effect on increasing blood pressure.

It can also cause anxiety, GI upset, fast heartbeat, insomnia, and even rhabdomyolysis (muscle breakdown).

It’s important to stick to no more than 400 milligrams of caffeine per day, or otherwise as instructed by your healthcare provider.

This means a daily caffeine limit may look like:

• 4 cups of brewed coffee, or
• 2 small energy drinks (with less than 200 milligrams of caffeine per can), or
• 6 to 8 cups of tea

Potassium in Coffee, Instant Coffee, and Espresso

Are there nutritional differences between coffee, instant coffee, and espresso? Yes and no.

None of these are sources of calories, carbohydrates, fats, nor protein.

However, coffee, instant coffee, and espresso can be significant sources of potassium if consumed in higher quantities.

Here’s a table comparing potassium differences between standard drinking servings of plain, unsweetened, black coffee, instant coffee, and espresso.

Type of Coffee	Serving Size	Potassium (mg/serving)
Brewed Regular (black)	8 fluid ounces	124
Brewed Decaf	8 fluid ounces	128
Instant	6 fluid ounces	54
Espresso	1 fluid ounce	34

If a person on a medically-required low potassium diet were to drink 4 cups of coffee in a day, they would be consuming approximately 500 milligrams of potassium.

That would mean they could be consuming up to 25% of their daily potassium goal from black coffee alone.

Additionally, this would not account for any additional potassium from coffee creamers or milk.

Canned coffee drinks can oftentimes be much higher in potassium.

In fact, a 15-ounce can of Starbucks Double Shot has a shocking 1,030 milligrams of potassium (not to mention added phosphates).

Added Sugar

Other things to pay attention to are the extras you may put in your coffee, like flavored creamers and sugar.

Adding too much of sugary creamers can increase blood sugar spikes and add extra potassium and/or phosphorus.

Many coffee-shop-style beverages are to blame when it comes to letting coffee become bad for kidneys, but there are ways to make sure your fast food coffee order is a good choice.

If you find that you do not like the taste of coffee without adding a lot of sugar, saturated fats, or potassium or phosphate additives, it may be better for you to research other options.

Bottom Line: Does Coffee Hurt Your Kidneys?

Black coffee does not hurt your kidneys. In fact, drinking black coffee regularly in moderation may be protective in several ways.

If you don’t like drinking coffee black, here are some tips on how to make the best kidney-friendly choices.

Kidney-Friendly Coffee Tips

As stated earlier, there are benefits to including coffee. There are, however, smart choices and risky choices when it comes to prepping your cup.

This is related to the sugars, creamers, and milks that are added to coffee rather than the coffee itself.

Choose Kidney-Friendly Coffee Creamers

Many coffee creamers come with added phosphates. This can be especially true in powdered creamers.

Check the refrigerated section to have your best pick of additive-free coffee creamers, including CoffeeMate® Natural Bliss line.

Many plant-based options like Sweet Oat Milk are kidney-friendly as well.

Other creamers that make good coffee for kidney disease include the Starbucks® Cinnamon Dolce creamer and even Silk® half-and-half replacement.

If you prefer plain milk, you have plenty of kidney-friendly milk to choose from! Add in kidney-friendly sweeteners if you want that added touch of sweetness.

Added Sugars in Creamers

The daily recommendation for added sugar from the American Heart Association is:

• No more than 36 grams (9 teaspoons) per day for men
• No more than 25 grams (6 teaspoons) per day for women

The World Health Organization (WHO) and American Dietary Guidelines recommend no more than 10% of calories come from added sugar.

This would equal about 50 grams (12 teaspoons) per day in a 2,000 calorie day.

Flavored coffee creamers will generally have about 5 grams of added sugar per tablespoon.

Therefore, sticking to 2-3 tablespoons of creamers will total to 15-20 grams of added sugar, keeping you under the daily added sugar allowance.

And it may even give you some room to enjoy kidney-friendly desserts.

Kidney-Friendly Alternatives to Coffee

If you feel you can’t make some of the changes mentioned above and still enjoy your coffee, here are some tips on how you can get benefits without drinking more coffee.

For an Energy Boost

Try going for a short and casual walk around the block! If the weather isn’t nice to walk in, even some stretching and moving around the house can be a great way to get blood flowing.

If you like to be productive while you move around, try unloading the dishwasher or making the bed to start your day off right.

For a Warm Mug

Need something hot to warm you up? Try switching your coffee for a kidney-friendly tea like black tea, green tea, or peppermint tea.

Another great kidney-friendly warming beverage is an antioxidant rich golden milk.

For a Morning Ritual

If you drink coffee simply from it being a morning habit, try replacing it with another habit.

Start practicing some mindful gratitude meditation or gentle yoga to center yourself and gently prepare for your day.

Summary

For most people, coffee can absolutely have a place in a kidney-friendly lifestyle. The research consistently shows that moderate coffee consumption (especially when enjoyed black or with kidney-friendly add-ins) does not harm kidney function and may even offer protective benefits against conditions like chronic kidney disease, diabetes, and cardiovascular disease.

Mushroom coffee has yet to be clinically proven helpful for people with kidney disease or damage. The risks outweigh the potential benefits, which have not been studied in people with kidney disease.

When it comes to coffee in a kidney-friendly diet, moderation remains key. Pay attention to your total caffeine intake, fluid allowance, and add-ins like creamers or sweeteners that can add unnecessary and excessive sugars, potassium, or phosphorus.

These factors often determine whether a cup of coffee supports your kidney health or works against it.

If you enjoy coffee as part of your morning ritual, you don’t need to give it up. Instead, make mindful adjustments to how you prepare and portion it. And remember, your exact needs will depend on your kidney function and overall health goals.

For personalized guidance, talk with your renal dietitian about the amount and type of coffee that best fits your daily plan. With balance and awareness, you can continue to savor your coffee while protecting your kidney function.