Phosphorus, potassium, and protein are of particular importance to people living with chronic kidney disease (CKD). While these nutrients are necessary to good health and normal body function, too much of any one of them can be harmful.

Healthy kidneys remove excess phosphorus*, potassium**, and protein*** byproducts from your bloodstream. When you have CKD, however, your kidneys aren’t able to perform this function, so you need to find other ways to control these substances in your body.

Adjusting your diet is the best—and most simple—way to do that. The National Kidney Foundation explains how.

Kidneys and essential nutrients

The main function of your kidneys is to filter wastes out of your bloodstream. When we think of wastes, it’s natural to think of toxins, but wastes also include excess fluids, minerals, and byproducts that our bodies can’t process or don’t need.

To stay healthy, the human body needs six essential nutrients daily:

• protein;
• vitamins;
• minerals;
• fats;
• carbohydrates; and
• water.

Phosphorus

Phosphorus works with calcium to build and maintain strong bones, but too much phosphorus weakens your bones by leaching calcium out of them. This can also lead to calcium deposits in your blood vessels, lungs, eyes, and heart—increasing your risk for heart attack and stroke.

Phosphorus is naturally found in many foods, especially protein-rich foods, including:

• red meats, especially organ meats, deli meats, and cured meats;
• seafood, such as sardines and oysters;
• dairy (milk-based) products;
• beans; and
• nuts.

It’s also frequently added as a preservative to:

• canned and bottled drinks, like beer, ale, dark colas, and iced tea;
• fast foods, such as hot dogs and pizza; and
• candies and confections, including chocolates and caramels.

Phosphorus is also found in most pre-packaged food items. It may appear on food labels as dicalcium phosphate, phosphoric acid, or any other ingredient that has some form of “phosphate” in the name.

A few healthy foods low in phosphorus include:

• certain beverages, like water, naturally caffeine-free herbal teas, unenriched rice milk, apple juice, and cranberry juice; 
• certain proteins, like eggs or minimally-processed turkey, beef, veal, or lamb;
• fresh fruits and vegetables, such as apples, berries, carrots, and cucumber slices; and
• unsalted pretzels, popcorn, and crackers.

Potassium

Potassium is found in most foods. It helps keep your heartbeat regular and your muscles moving smoothly. 

Because they’re naturally high in potassium, it’s best to limit the following foods:

• bananas, cantaloupe, mangos, and oranges;
• brussels sprouts, broccoli, and spinach;
• carrots, pumpkin, and tomatoes;
• beans and potatoes;
• nuts, nut butters, and seeds; 
• dairy products and milk chocolate; and
• salt and salt substitutes. 

Some tasty, healthy foods that are low in potassium include:

• apples, berries, and cherries;
• asparagus, celery, and cucumbers;
• cauliflower, eggplant, and zucchini;
• corn, onions, peppers;
• cabbage, kale, and lettuce; and
• noodles, pasta, and rice.

Protein

Protein is one of your body’s main sources of fuel. It also builds muscle and helps fight infection. How much protein a person needs daily differs by age, sex, and various health factors. Moreover, not all protein sources are equal in terms of nourishment. 

Animal proteins—like eggs, fish, poultry, and red meat—contain all the essential amino acids and are considered “complete” proteins. Unfortunately, they can also be high in cholesterol and unhealthy fats, which are bad for your heart. 

Poultry is generally less fatty than red meats, and fish is less fatty than poultry. Eggs can be made more heart-healthy by ditching the yolk, which are high in cholesterol. In doing so, though, you lose the good vitamins and minerals that are naturally found in the yolk.

Plant proteins include:

• beans,
• lentils,
• nuts,
• seeds, and
• whole grains.

However, plant proteins are not complete proteins by themselves. They can become complete proteins when combined with another food item, such as peanut butter on whole grain bread. 

Other types of food, like cereals, pasta, fruits, and vegetables, offer less protein, but they also provide helpful dietary fiber, vitamins, and minerals.

Creating a kidney-healthy diet

Moderation and variety are the keys to a balanced nutrition for people living with CKD. Working with your doctor and dietician can help you craft a healthy, enjoyable diet that best suits your body’s needs.

*National Kidney Foundation. (2020). Phosphorus and Your Diet.

**National Kidney Foundation. (2020). Potassium and Your CKD Diet.

***Ulerich, L. (2020). “News – Protein in Our Diet – Variety and Moderation is the Key.” National Kidney Foundation.