The 5 Best Drinks If You Have Bad Kidneys (and a Few to Avoid)

The kidneys are constantly filtering the fluids in your body to get rid of toxins and waste. So, it probably comes as no surprise that what you drink can affect your kidney function. And if you have any type of kidney disease — whether it’s from a chronic condition or a temporary illness — paying attention to your fluid intake is particularly important. 

We’ll go through five drinks and juices that can help your kidneys function at their best. 

1. Water

About 60% to 70% of your body is water. And your kidneys rely on water to make urine, which is how they remove waste from your body. Water also helps to keep your blood vessels open so that blood can reach your organs, including your kidneys.

You help protect your kidneys when you drink enough water each day. One study showed that people who drank almost 2 L of water daily were less likely to develop kidney problems. This was especially true for older adults and men. 

Drinking water when you have kidney disease 

But what about people who already have decreased kidney function? Some studies have looked at whether drinking water can increase your glomerular filtration rate (GFR), which is a way to measure kidney function. The higher your GFR, the better your kidneys function. 

One study found that when people with kidney disease drank more water, their GFR didn’t increase. But another study showed that people who drank more water were more likely to have a higher GFR. And, similarly, people who drank less water were more likely to have a lower GFR.

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• Is coffee bad for kidneys? Take a deeper dive into how coffee impacts kidney and liver health. 

• Drinks that lower blood pressure: Maintaining a normal blood pressure is one of the best ways to protect your kidneys. These drinks can help.

• How much water should you drink? The answer is a bit more complicated than the repeated “8 glasses a day.” Learn what’s the right amount for you.

So, at the end of the day, it’s unclear if drinking water can improve kidney function in people with kidney disease. But if you have low kidney function, staying hydrated can help keep your kidneys working better. Severe dehydration can actually lead to kidney damage, making kidney disease worse. And even mild dehydration, if it happens too often, can cause kidney damage. Dehydration ultimately leads to the buildup of waste in your body, making your kidneys work harder to remove it.

Some people with chronic kidney disease may need to monitor their fluid intake more than others. If you have late-stage kidney failure or require dialysis, too much fluid can overwhelm your kidneys and cause other health issues. A healthcare professional can help you figure out the right amount of fluid for you, based on your kidney function and overall health.

2. Low-fat milk

One long-term study found that people with chronic kidney disease who drank low-fat milk had a slower decline of their kidney disease. In other words, their kidneys worked better for longer.

Scientists think that certain nutrients in dairy — like calcium, potassium, vitamin D, and magnesium — may help lower blood pressure and protect the kidneys. Of note, the researchers didn’t see that same benefit in people who drank high-fat milk. So it’s possible that too much fat content may decrease the potential benefits of milk.

3. Coffee

Have you ever wondered, “Is coffee bad for your kidneys?” This is a common question on people’s minds. But experts actually believe that coffee may help protect your kidneys. Research shows that coffee consumption is associated with a lower risk of developing kidney disease. This may be because it improves blood sugar and lowers inflammation in the kidneys. But it’s not clear if it can slow how quickly kidney disease worsens. 

In one study, participants who drank 1 or more cups of coffee daily had a lower risk of death from kidney disease compared to people who never drank coffee. Another study found that people who drank 3 cups of coffee a day had an even lower risk of disease. 

But these studies didn’t find a similar benefit in people who already had poor kidney function. So, coffee may not have the same protective effects for people with kidney disease. 

If you have kidney disease and like drinking coffee, keep these things in mind:

• Avoid excessive amounts of coffee. That’s because large amounts of coffee can be high in potassium, which can lead to high potassium levels in someone with bad kidneys. To make sure you’re not drinking too much, aim for fewer than 3 cups a day. 

• Drink plain, black coffee. Added ingredients can be harmful. For example, syrups can be high in potassium and phosphorus. They may also contain a lot of sugar.

• Consider drinking decaf. That’s if regular coffee increases your blood pressure. More research is needed to know whether caffeine adds to the health benefits of coffee. But experts do know that a spike in blood pressure is hard on the kidneys.

4. Green tea

Green tea contains catechins, which are antioxidants. Antioxidants help decrease inflammation in the body, which can be helpful for your kidneys. Green tea has also been shown to decrease the risk of kidney stones. 

In particular, green tea contains the catechin epigallocatechin-3-gallate (EGCG), which may be helpful for people with kidney disease. Several studies have shown that it can slow the decline of chronic kidney disease. But it’s important to note that these studies were done in the lab in “disease models,” not in actual humans. 

So, just like coffee, it’s best to drink green tea in moderation if you have kidney disease.

5. Unsweetened cranberry juice

You may have heard that cranberry juice is good for kidneys. Cranberries are rich in flavonoids, another type of antioxidant that may be particularly good for kidneys. 

Many people drink cranberry juice specifically to help prevent UTIs (urinary tract infections). And research suggests it may help prevent bacteria from sticking to the urinary tract. 

People with kidney disease need to be extra careful about preventing UTIs. Some UTIs can lead to pyelonephritis — an infection in the kidneys. Scientists think that cranberries also interfere with bacteria sticking to the kidneys, just like they prevent it from sticking to the urinary tract. 

Look for low-sugar or unsweetened options. Extra sugar can increase blood sugar and blood pressure, both of which are harmful to your kidneys.

What drinks should people with kidney disease avoid?

If you have kidney disease, do your best to avoid or cut back on:

• Cola beverages: Studies show that drinking 2 or more cola drinks a day may be harmful for people with kidney disease. Experts believe the phosphoric acid in cola drinks can strip calcium from bones, increasing the risk of kidney stones and kidney failure.

• Alcohol: Drinking alcohol makes your kidneys less able to filter your blood and increases blood pressure, which can lead to kidney damage.

• Sugary beverages: Sweetened drinks can harm the kidneys in several ways. They increase blood sugar, blood pressure, and inflammation in your body. Sugary drinks can also contribute to weight gain, which further increases the risk for these harms for your kidneys.

There’s some evidence that drinking 2 or more diet colas a day may also worsen kidney function. But the study was done only in white females, so more research is needed in different populations of people. 

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Written by:

Cherilyn Davis, MD

Cherilyn Davis, MD, is a board-certified pediatrician in New York City. She has held local and national roles at the American Medical Women’s Association including board member of the physician division and physician chair of social media.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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