A low potassium diet may reduce the burden on the kidneys and keep potassium levels in check, which is key for people with some chronic conditions.

Potassium is a mineral in a variety of foods, and it plays many important roles in the body, including keeping fluid levels balanced.

The kidneys usually filter the blood and help keep potassium levels stable, but some health issues limit their ability to do this.

This article looks at why and for whom monitoring dietary potassium is important. It also explores which foods to eat, which to avoid, and how to prepare foods so that they contain less of the mineral.

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Potassium is a key electrolyte in the body. It helps with the function of cells generally, and it supports the function of the kidneys, nerves, heart, and muscles.

Potassium also interacts with sodium. Without enough potassium in the body, high sodium levels may lead to an increase in blood pressure.

A combination of low potassium and high sodium levels may increase a person’s risk of heart disease and stroke. Also, if potassium levels are too high or low, the risk of serious heart conditions, including cardiac arrest, rises.

The kidneys help filter the blood, and in doing so they balance out levels of electrolytes — such as potassium — in the blood.

The average healthy person likely does not need to reduce their potassium levels. In the United States, for example, people tend to have too little potassium in their diets. And if a healthy person consumes too much, their kidneys typically excrete the excess through the urine.

However, diminished kidney function, due to an issue such as chronic kidney disease, can throw electrolyte levels out of balance. If potassium levels are too high, doctors call this hyperkalemia.

Meanwhile, certain medicines for kidney disease can also contribute to an imbalance.

Other health conditions that can affect potassium levels include:

A person with any of the above health issues should work closely with a healthcare professional to keep their potassium levels in check.

Healthcare professionals may recommend dietary changes to help reduce potassium levels.

This will require a person to become familiar with the potassium contents of various foods and choose low potassium options whenever possible. Also, it is important to limit the portion sizes of high potassium foods.

Meanwhile, doctors may also recommend medications that help remove the mineral from the body.

Making dietary changes can help limit potassium levels, but it is important to keep in mind that the nutrient is crucial for health. The goal is to choose foods that provide enough of the mineral without causing a problematic buildup.

The National Kidney Foundation report that a potassium-restricted diet should include about 2,000 milligrams (mg) of the mineral each day. However, a doctor may recommend a different target.

Fruits

Low potassium fruits include:

  • apples (1 medium) or apple juice or sauce
  • blueberries
  • blackberries
  • strawberries
  • raspberries
  • cherries
  • grapes or grape juice
  • cranberries or cranberry juice
  • pineapple or pineapple juice
  • mandarin oranges
  • grapefruit (1/2 fruit)
  • watermelon (1 cup)
  • plum (1 whole)
  • tangerine (1 whole)
  • peaches (1 small)

Vegetables

Low potassium vegetables include:

  • green beans
  • wax beans
  • peas
  • alfalfa sprouts
  • green or red cabbage
  • raw white mushrooms
  • cucumber
  • eggplant
  • kale
  • lettuce
  • onions
  • peppers
  • parsley
  • rhubarb
  • radishes
  • watercress
  • yellow or zucchini squash
  • asparagus (6 spears)
  • celery (1 stalk)
  • corn, fresh (½ ear)

Protein sources

Beyond vegetable sources, other low potassium sources of protein include:

  • eggs
  • canned tuna
  • beef
  • poultry
  • some cheeses

Carbohydrate sources

Low potassium foods rich in carbohydrates include:

  • white rice
  • white bread
  • white pasta
  • corn products, such as polenta and cornmeal grits

Drinks and snacks

Some low potassium options include:

  • rice milk
  • coffee
  • tea
  • herbal tea
  • sparkling water
  • cakes and pies without chocolate or fruits high in potassium
  • cookies without chocolate or nuts

High potassium foods contain more than 200 mg of potassium per serving.

Below, we have listed some foods that anyone looking to reduce their potassium intake might want to avoid.

Unless a serving size is provided, the average serving is 1/2 cup. It is worth noting that simply reducing the serving size, and thus the amount of potassium, may make some of these foods acceptable.

Fruits

The following are fruits with more potassium and their average serving sizes:

  • raw apricots (2 medium)
  • dried apricots (5 halves)
  • dates (5 whole)
  • other dried fruits
  • avocados (¼ whole)
  • bananas (½ whole)
  • cantaloupe
  • honeydew melon
  • grapefruit juice
  • kiwi (1 medium)
  • mango (1 medium)
  • nectarine (1 medium)
  • orange (1 medium)
  • orange juice
  • papaya (½ fruit)
  • pomegranate (1 whole)
  • pomegranate juice
  • prunes
  • prune juice
  • raisins

Vegetables

Below, find vegetables with more potassium:

  • acorn squash
  • artichokes
  • bamboo shoots
  • butternut squash
  • boiled beets
  • cooked broccoli
  • brussels sprouts
  • Chinese cabbage
  • raw carrots
  • leafy greens, except kale
  • hubbard squash
  • kohlrabi
  • okra
  • parsnips
  • potatoes
  • pumpkin
  • rutabagas
  • cooked spinach
  • tomatoes
  • cooked white mushrooms

Nuts, seeds, beans, and legumes

Below, find legumes, beans, and seeds with more potassium:

  • baked beans
  • black beans
  • nuts and seeds (1 ounce)
  • peanut butter (2 tablespoons)
  • dried beans and peas
  • lentils
  • legumes

Other foods to avoid

  • bran products
  • chocolate (1.5–2.0 ounces)
  • granola
  • milk, all types (1 cup)
  • molasses (1 tablespoon)
  • salt-free broth
  • yogurt

People looking to limit their potassium levels may also need to avoid salt substitutes, which can contain higher levels of minerals, including potassium.

Leaching is a technique to draw some potassium from foods. A person should contact a doctor about the best approach and how much to leach before trying it at home.

To leach potassium from some vegetables, for example:

  1. Peel and rinse the vegetables under warm water.
  2. Cut the vegetables into pieces that are 1/8 inch thick.
  3. Soak them in warm water for at least 2 hours. Use 10 times as much water as there are vegetables.
  4. Rinse them under warm water again.
  5. Boil them, using 5 times as much water as there are vegetables.

For some, this may be too time-consuming. Alternately, an older study, from 2008, found that simply boiling some potassium-rich foods, such as cubed potatoes, for 10 minutes can reduce their potassium contents by up to 50%.

For canned or potted fruits and vegetables, drain and rinse them to remove any excess minerals in the canning liquid.

Potassium is a key mineral that supports a variety of important functions.
A person with a health issue affecting their kidneys or adrenal system may need to prevent this mineral from building up and must closely monitor their potassium intake.

A doctor may recommend a low potassium diet. It is important to work with them closely to monitor potassium levels and keep them in check.