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What to eat (and avoid) if you have kidney disease

Bowl of oatmeal with fruit

If your kidneys aren’t filtering blood efficiently, you may need to adjust your diet accordingly. Here are the foods to focus on.

Hallie Levine

By Hallie Levine

If you have chronic kidney disease, one of the most important things you can do is modify your diet.

“A kidney-friendly diet is really important,” says Melissa Ann Prest. She’s a registered dietitian nutritionist and a renal nutrition specialist in Chicago. “It can not only help protect your kidneys from further damage, but it can also help control high blood pressure or diabetes, both of which make kidney disease worse.”

Renal dietitians such as Prest can be an important part of your treatment. These nutrition specialists work specifically with people who have kidney disease. And the American Kidney Fund (AKF) notes that many insurers, including Medicare, will often pay for the service.

But to get you started, you can make plenty of changes right now to help keep your kidneys strong. (If you need help paying for your kidney medications, download the Optum Perks mobile app to access coupons instantly.)

Reduce your sodium intake

When your kidneys are damaged, they have a hard time processing salt. This can lead to sodium and fluid building up in your body, causing symptoms such as swollen ankles, high blood pressure and shortness of breath.

That’s why the National Kidney Foundation (NKF) says it’s important to limit salt and other forms of sodium even in the early stages of kidney disease. Aim to keep your intake below 2,300 milligrams per day. That’s about a third less than what the average person consumes, according to the U.S. Food and Drug Administration.

One easy way to reduce sodium: Prepare more meals in your own kitchen. Packaged, processed and restaurant foods often have the most salt, according to the Centers for Disease Control and Prevention.

Reduce your protein intake

As kidney disease gets worse, you may need to swap out your breakfast omelets for oatmeal. “A lower-protein diet may be advised for some people who have chronic kidney disease once they reach stage 4 or 5 but before they start dialysis,” says Michelle Routhenstein. She’s a registered dietitian in New York City. “This will depend on many factors that need to be individually assessed.”

To understand how protein becomes a problem, it helps to note that your kidneys play a key role in breaking it down. If they aren’t operating efficiently, then eating protein can lead to a buildup of ammonia in your blood. That makes kidney failure even worse.

Dialysis can help here. This treatment uses a machine to filter your blood. Your doctor will likely recommend it once your kidneys have lost 85% of their filtration power, according to the NKF.

Once you’re on dialysis, your protein needs will likely go back up, says Routhenstein. That means adding foods such as fish, beans and lean meat. Work with your doctor and nutritionist to figure out how much protein you should consume every day.

Follow a heart-healthy diet

If your kidneys are in trouble, then your heart is probably suffering, too. “Heart disease is the most common cause of death among people with kidney disease,” says Routhenstein.

But eating for heart health may protect both your heart and kidneys. A review published in Nutrition Journal looked at diets rich in foods considered healthy: vegetables, fruits, fish, low-fat milk and whole grains. People who ate these foods most often were 31% less likely to get chronic kidney disease (CKD).

Meanwhile, people who ate more Western-diet foods — refined grains, red and processed meat, desserts, butter, fast food and soda — were 86% more likely to develop CKD.

One way to eat for heart health is to follow the DASH diet. It’s been ranked as one of the best diets for heart health for more than 20 years.

Scale back on phosphorus and potassium

By filtering blood, healthy kidneys keep phosphorus and potassium at safe levels. But with kidney disease, these minerals can build up, says Prest.

“Too much phosphorus in your blood pulls calcium from your bones, making your bones thin, weak and more likely to break,” according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). “High levels of phosphorus in your blood can also cause itchy skin and bone and joint pain.”

To help you stay in the safe zone, your doctor can check phosphorus and potassium levels in your blood. While not everyone needs to avoid foods high in phosphorus and potassium, Prest says, your doctor may ask you to limit foods that contain high levels.

According to the National Institutes of Health, the foods high in phosphorus are cheese, meat, oats, fish, dark-colored soda, beans, nuts, seeds and packaged foods that include phosphorus additives.

For potassium, the foods to limit include salt substitutes, oranges, bananas, potatoes, tomatoes, brown rice, whole wheat and nuts. Beans, nuts, bran and dairy foods are often high in both phosphorus and potassium.

You may not have to cut these foods out of your diet, but you should be aware of your intake. The goal is to avoid taking in too much over the course of a day.

Take oats. Yes, they’re higher in phosphorus, but a randomized study from Clinical Nutrition found that eating a bowl a day, or about half a cup of dry oats, had a net positive effect for people with CKD. But that doesn’t mean more is better: You probably wouldn’t want to later eat a sandwich on oat bread with oatmeal cookies for dessert. You can work with your dietitian to plan meals that keep you in a safe range.

So what should you eat?

Changing your diet can be challenging, especially if you’re focused only on the things you have to avoid. To get you started on a positive note, here are 5 kidney-friendly foods you can stock up on.

Herbs and spices

Reach for your spice rack to season your food instead of using salt or bottled sauces full of sodium. Basil, curry, dill, ginger and rosemary can add flavor to any dish, whether it’s meat or a vegetable.

Feel free to experiment, but to help maximize the flavor, follow these tips from the NKF:

  • Add ground spices to food about 15 minutes before you finish cooking.
  • Combine herbs with oil and set for 30 minutes, and then brush on foods while they cook.
  • Purchase herbs and spices in small amounts. That way, they don’t lose flavor by spending years in a cupboard.

As a reminder, avoid salt substitutes. They often contain high levels of potassium, says Prest.

Berries

Blueberries, raspberries and strawberries are nutritional powerhouses that are also low in potassium, says Prest. She adds that they may help reduce your blood pressure, which is good for your kidneys.

Other fruits low in potassium include apples, cherries, peaches, plums, pears and grapes.

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Tofu

Every day in the United States, nearly 75% of people eat red meat, according to researchers from the University of North Carolina at Chapel Hill. But red meat isn’t ideal, says Routhenstein. It contains saturated fats and other compounds that can increase the risk of heart disease and stroke.

For those seeking healthier forms of protein, Routhenstein suggests plant-based proteins such as tofu. It’s easier on your heart, for starters. But because it’s lower in phosphorus and potassium, it’s also easier on your kidneys.

Cauliflower

If you’re limiting potassium, it’s best to avoid vegetables such as potatoes, sweet potatoes, carrots, beets and winter squash. But cruciferous veggies, such as cabbage or kale, are generally good, says the NKF.

Cauliflower is a great option here. If you’re craving mashed potatoes, just swap in mashed cauliflower instead.

Now, if you’re set on eating potassium-rich vegetables, there’s a trick that will pull out some of the potassium, says the NKF:

  • Slice the vegetables one-eighth inch thick.
  • Soak them for at least 2 hours in warm water, using 10 times as much water as vegetables.
  • Strain and then cook them with 5 times as much water as vegetables.

Cashew milk

Since cow’s milk is high in potassium and phosphorus, many people with kidney disease switch to rice milk. But rice milk has little nutritional value, says Routhenstein. “I recommend unenriched cashew milk instead — it has a nutty flavor and creaminess, and it’s heart-healthy,” she says.

Diet can have a huge impact on the health of your kidneys, but you still may need medication. So download the Optum Perks discount card to be ready. All you have to do is show it to the pharmacist at checkout to see if there’s a cheaper price available.

 

Additional sources

Nutrition and Kidney Disease: National Kidney Foundation

Diet and chronic kidney disease: American Kidney Fund

Average sodium consumption 3,400 mg: U.S. Food and Drug Administration

Sodium and CKD: National Kidney Foundation

Dialysis overview: National Kidney Foundation

Top sources of sodium: Centers for Disease Control and Prevention

Diet and chronic kidney disease: Nutrition Journal (2021). “Dietary patterns and chronic kidney disease risk: a systematic review and updated meta-analysis of observational studies

Phosphorus and potassium: National Institutes of Health

Oats and CKD: Clinical Nutrition (2016). “The impact of oat (Avena sativa) consumption on biomarkers of renal function in patients with chronic kidney disease: A parallel randomized clinical trial

U.S. red meat consumption: International Journal of Environmental Research and Public Health (2021). “Patterns of red and processed meat consumption across North America: A nationally representative cross-sectional comparison of dietary recalls from Canada, Mexico, and the United States

Trimethylamine N-oxide (TMAO): Cleveland Heart Lab

Eating foods with potassium: National Kidney Foundation