Diet for Chronic Kidney Disease

Having chronic kidney disease (CKD) means watching what you eat. But what exactly is it you’re watching for? And why does it matter?

Nephrologist Hernán Rincón-Choles, MD, breaks down the principles of a CKD diet.

What is the best diet for CKD patients?

Not everybody who has CKD needs to be on a restrictive renal diet, but there are certain dietary principles you’ll want to follow no matter what stage of CKD you’re in. They include:

• Monitoring your sodium, protein, potassium and phosphorus intake: We’ll come back to this in a bit.
• Staying well hydrated: “Ideally, you should drink at least 2.5 liters of fluid — 10.5 glasses — throughout the day,” Dr. Rincón-Choles says. But there are some exceptions, like when you have kidney stones or kidney failure. Talk to your nephrologist or a renal dietitian for tailored advice.
• Focusing on “whole foods”: Eating ultra-processed foods raises your risk of developing or worsening CKD. When you can, opt for minimally processed, nutrient-rich foods.
• Protecting your heart: You may be surprised to hear that heart disease is a leading cause of death for people with CKD. You can reduce your risk by limiting your intake of foods that are high in cholesterol and saturated fat. Examples include fatty meats, fried foods and full-fat dairy.
• Managing chronic illnesses: It’s common to have other health conditions on top of CKD. If that’s you, make sure your eating plan accommodates those dietary needs, too.

Why diet matters for CKD

Following a CKD-friendly eating plan helps relieve stress on your kidneys, which can slow disease progression and manage or reduce your risk of related chronic conditions. To understand why, it helps to understand what’s happening in your body when you have CKD.

Dr. Rincón-Choles explains that your kidneys perform more than 20 different functions. One of them is filtering fluid and waste out of your blood and eliminating them from your body in the form of pee (urine).

Imagine an assembly line in a busy factory, with your blood traveling down the conveyor belt. When you have CKD, it’s like the conveyor belt is moving too fast for your kidneys to perform those 20+ jobs properly.

Our bodies don’t have off buttons, and your kidneys can’t remove the waste and fluid from your blood as fast as they need to. So, eventually, that waste and fluid build up, causing new damage and slowing things down even more.

While adjusting your eating habits can’t undo the damage your kidneys have already sustained, it may slow or even stop further decline.

Key nutrients to watch

Dr. Rincón-Choles says managing CKD often requires close monitoring of the following four nutrients:

Sodium

If you’ve ever noticed that your body retains more water when you eat a salty meal, it’s probably not surprising that reducing your sodium intake is one of the hallmarks of a CKD diet. It’s one thing to be well hydrated. It’s quite another to carry around fluid your body doesn’t need.

“Sodium raises your fluid levels and, potentially, your blood pressure, too,” Dr. Rincón-Choles explains. In other words, you’re asking your already overtaxed kidneys to work even harder — and you’re putting unneeded stress on your heart at the same time.

Protein

While most people may think about kidneys first and foremost as organs that clean our blood, Dr. Rincón-Choles shares that they’re also responsible for breaking down the proteins that we eat. So, when your kidneys aren’t working properly, protein buildup can become a problem.

“After your kidneys break protein down into amino acids and peptides, they have to reabsorb it and send it back to the bloodstream, so you don’t lose it through your urine,” he explains. “If you eat excessive amounts of protein, especially animal proteins, you’ll overwhelm your kidneys, leading to proteinuria, or protein in your pee.”

In other words, the protein you eat ends up in your toilet, not your blood.

Having CKD doesn’t mean you have to go vegetarian, but it does mean you need to get the majority of your protein from plants.

But how much protein are we talking about? The exact amount varies based on the severity of your condition. But Dr. Rincón-Choles says that most people with CKD should aim to eat about 1 gram of protein for each kilogram of their body weight.

Potassium

As kidney function declines, so does their ability to filter potassium, an essential mineral that helps regulate your fluid levels and support your heart and other muscles. Out-of-whack potassium levels can lead to a wide range of issues, including high blood pressure.

How much you need to limit your potassium intake depends on how damaged your kidneys are. Potassium-heavy foods to cut down on include potatoes, tomatoes and whole grains.

Phosphorus

When excess phosphorus builds up in your blood, it can hurt the same body systems the nutrient usually supports. For example, phosphorus, like calcium, helps keep your bones strong. But when there’s too much of it, your bones try to compensate by leeching calcium. Those calcium deposits then end up in places you don’t want them, including your heart.

Limit your intake of food that’s rich in phosphorus, like nuts, organ meat and dairy. You should also avoid foods with added phosphates, like microwave meals, sodas and processed meats.

Working with a renal dietitian

Working with a renal dietitian is a great way to take the guesswork out of CKD nutrition and find an eating plan that meets your needs. They can:

• Teach you about the role that eating habits play in CKD progression.
• Share grocery lists and meal prep advice.
• Help you address any complications as they arise.

If you haven’t met with a renal dietitian, ask your nephrologist for a referral. Renal dietitians work primarily with people in later stages of CKD, but it’s also good to see them when your kidney function changes. If you progress from stage 3 to stage 4, for example, your diet may need to be tweaked.

Final thoughts

It can be overwhelming realizing how big a role the food you eat can have in your CKD journey. And it’s normal to have lots of questions. That’s where your provider comes in.

“Your nephrologist can answer questions and connect you with resources to better understand your condition and change your eating habits,” Dr. Rincón-Choles reassures. “Those and other lifestyle adjustments won’t always be easy, but they can make a really positive difference in your overall health.”