Potassium: Health Benefits, Food Sources, and More

You’ve probably heard of potassium. The well-known nutrient may even conjure up vague images of bananas, electrolyte balance, and muscle cramping. But what exactly is this important nutrient, and where can you get it?

Potassium is actually a mineral that is essential for muscle function. (1) It relaxes the walls of the blood vessels, which in turn lowers high blood pressure (hypertension) and can help against cramping. (1) Potassium does so by ensuring that there’s a normal water balance between the cells and the fluid outside of them, and that certain enzymes in your cells are able to work properly. (2)

But it’s also an interesting nutrient because both too little potassium (called hypokalemia) and too much potassium (called hyperkalemia) can lead to health problems. And, for certain people, like those with kidney disease, potassium can actually be a tricky nutrient to maneuver around.

So how much potassium does an average, healthy adult need? About 4,700 milligrams (mg) per day. (3) Here are just a few great sources of potassium, from the Academy of Nutrition and Dietetics: (3)

• 1 medium baked potato with skin: 930mg
• 1 cup cooked spinach: 840mg
• 1 cup cubed cantaloupe: 430mg
• 1 medium banana: 420mg
• 1 cup chopped carrots: 410mg
• 1 cup low-fat milk: 350 to 380mg
• 1 cup cooked quinoa: 320mg

Some people, especially those with kidney problems, may benefit from a low-potassium diet.

Potassium is an essential part of your diet, and can even help you manage your high blood pressure. (4) That’s because potassium actually helps you reduce the effects of sodium on your body — when you eat more potassium, you actually expel more sodium through your urine. (4) The American Heart Association recommends that adults with blood pressure above 120/80 millimeters of mercury (mmHg), who are otherwise healthy and have no underlying kidney disease, increase the amount of potassium in their diet. (4)

A number of studies have backed up the power of potassium. One 2017 study looked at how potassium-enriched salt could provide some benefits for patients recovering from stroke. (5) The study looked at just under 300 discharged stroke patients and divided them into three populations: those who were given regular salt, those who were given potassium-enriched salt, and those who were given potassium- and magnesium-enriched salt.

Researchers then evaluated the neurological performance of the stroke patients at zero months, three months, and six months. After six months, they found that patients who were given the potassium- and magnesium-enriched salt had the best neurological performance, followed by patients with potassium-enriched salt only, and then finally patients who had consumed regular salt. The researchers concluded that magnesium and potassium together could have strong benefits for patients recovering from strokes.

Potassium is important, but not everyone is getting enough. One review noted that humans are actually consuming less and less potassium as we eat more processed foods and fewer fruits and vegetables. (6) By some estimates, the researchers say, we’re only eating about one-third as much potassium as past generations. The review went on to assess a number of studies that showed high-potassium diets can help lower high blood pressure and thus reduce risk of death from heart disease. High-potassium diets can also slow the progress of kidney disease, the researchers explain, and may help decrease the risk of kidney stones and osteoporosis. Finally, the researchers add that low levels of potassium in the blood are associated with glucose intolerance, and that increasing your potassium intake could help prevent the development of type 2 diabetes.

As essential as potassium is, it’s not all about trying to increase your potassium intake. Both too little and too much potassium in your blood can cause some major health concerns — and often, there aren’t any symptoms of either issue.

Some people are more at risk for developing high potassium levels than others. Your kidneys help regulate the amount of potassium in your body. (1) People who have kidney problems, such as chronic kidney disease, should not consume too much potassium — if they do, they could develop an excess of potassium in their blood, which again is referred to as hyperkalemia. (1,7)

A blood test can indicate if you have hyperkalemia: A normal potassium range is about 3.6 to 5.2 millimoles per liter (mmol/L), while levels higher than 6 mmol/L are considered dangerous. (8) It’s important to be aware of your potassium levels, as hyperkalemia often causes no symptoms. But at extremely high levels, hyperkalemia can cause an irregular heartbeat, nausea, muscle weakness, paralysis, and even death. (7,8) In these cases, excessively high potassium levels may require emergency medication or dialysis. (8)

Low levels of potassium, hypokalemia, can also have a significant impact on your health. The most common cause is prescription medication that increases urination, which leads to the body expelling too much potassium in the urine. (9) Other causes could include alcoholism, trauma, or surgical procedures. (10) Vomiting, diarrhea, and, sometimes, not enough potassium in the diet, can also cause low potassium levels. (9) Again, symptoms may be hard to diagnose: You may experience weakness, fatigue, muscle cramps, or constipation, or even an irregular heartbeat. (9)

For patients with low potassium levels, doctors may prescribe potassium supplements — but make sure you don’t take them on your own without consulting a doctor first. (9) Also make sure to ask your doctor before trying salt substitutes, as these can potentially increase potassium levels in the blood for some people. (4)

As per the U.S. Department of Agriculture’s MyPlate guidelines, potassium is found in a wide range of fruits, vegetables, and even animal products. Potential sources of potassium can include: (1,2,3,4)

• Leafy greens, like spinach or collard greens
• Fruits, including blackberries, grapes, tomatoes, oranges, nectarines, grapefruit, honeydew melons, cantaloupe, kiwi, prune juice, and bananas
• Vegetables, including carrots, potatoes, sweet potatoes, butternut squash, broccoli, zucchini, eggplant, pumpkins, cucumbers, and water chestnuts
• Beans, such as lima beans
• Nuts and seeds, like pistachios, almonds, and pumpkin seeds
• Dairy foods, including fat-free yogurt and fat-free or low-fat milk
• Meat, poultry, and fish, such as halibut and tuna
• Molasses

1. Which foods are highest in potassium?

Foods high in potassium include the following, all of which have more than 200 mg per one-half cup serving: (11)

• Apricots
• Artichokes
• Avocados
• Bananas
• Beets
• Brussels sprouts
• Cantaloupe
• Dates
• Oranges
• Potatoes
• Pumpkin
• Spinach (cooked)
• Sweet potatoes
• Tomatoes

2. Which foods are relatively low in potassium?

If you’re limiting potassium, some of these foods are safer bets (all contain less than 100 mg per one-half cup serving): (11)

• Blueberries
• Cabbage
• Okra
• Onion
• Pineapple
• Raspberries
• Watermelon

3. What is the function of potassium, in a nutshell?

Potassium helps your muscles contract, your nerves function, your heartbeat remain regular, and your cells to retain a proper fluid and electrolyte balance. (3) It can even help reduce your risk of kidney stones and bone loss as you get older. (3)

4. What happens if you have a low potassium level?

Low potassium levels can be just as dangerous as high potassium levels. You may experience weakness, fatigue, and muscle cramps, all of which may require immediate treatment. (9) Sometimes, you may have no symptoms at all — a blood test can confirm whether your potassium levels are abnormally low or high. (9)

5. How much potassium do you need in a day?

While most Americans consume about 3,500 to 4,500 mg per day, the recommended amount is 4,700 mg per day, showing most Americans don’t get enough potassium. (3,12) People who are restricting their potassium typically limit themselves to about 2,000 mg per day. (12)

6. If you’re on a low-potassium diet, how do you prevent yourself from eating too much potassium?

First, try to avoid eating too many high-potassium foods. Track what you eat, or work with your physician to come up with some other strategies.

But, if you want to enjoy some high-potassium vegetables, you can actually use a process called leaching to take some of the potassium out. For vegetables like potatoes, sweet potatoes, corn, beets, and squash, peel and slice the vegetables, rinse the veggies in warm water, and then cook the veggies with five times the amount of water as you typically would. Try to stick to a ratio of water to vegetables of about 10:1. (12)

Just keep in mind that even if you’re leaching vegetables, you’ll need to limit your intake if you’re on a low-potassium diet. Be sure to work with a registered dietitian nutritionist to determine a safe number of veggies for you.