Potassium: Benefits, Immune Support and How Much You Need

Potassium is a mineral your body needs for almost everything it does, from keeping your heart beating steadily to helping your muscles contract and your nerves send signals [1]. Unlike most of the nutrients on this site, potassium comes almost entirely from food, which makes what's on your plate especially important [1].

What is potassium?

Potassium is a mineral found in many of the foods we eat, especially fruits, vegetables, beans and dairy [1]. Your body absorbs about 85% to 90% of the potassium in your food, and your kidneys keep the balance by flushing out what you don't need [1].

Here's what makes potassium special. Almost all of it lives inside your cells, at a concentration about 30 times higher than outside them. That difference works a bit like a battery, creating the electrical charge your nerves and muscles use to do their work [1]. Potassium also works closely with sodium to manage the fluid balance in your body [1].

And yes, it's available in supplements, but most provide only small amounts, no more than 99 mg per serving [1].

What does potassium do for the body?

Potassium's best-known job is keeping your heart, muscles and nerves working the way they should [1].

Potassium is important to five things inside the human body: the heart, the muscles, the nerves, the kidneys and fluid balance, and the immune system. Let's take each one individually.

• The heart: Potassium is needed for proper heart function and a steady heartbeat [1].
• The muscles: Your muscles need potassium to contract [1].
• The nerves: Potassium helps your nerves carry signals throughout your body [1].
• The kidneys and fluid balance: Potassium supports proper kidney function and works with sodium to manage the fluid in and around your cells [1].
• The immune system: And the last one. Potassium channels on your T cells help set the electrical charge those cells need to switch on [2] [3].

Why is potassium important for the human body?

When you don't get enough potassium from food over time, it can raise your blood pressure, pull calcium from your bones and raise your risk of kidney stones [1]. On the flip side, diets rich in potassium are linked to lower blood pressure and a lower risk of stroke, especially when they're also lower in sodium [1].

Truly low blood potassium, called hypokalemia, usually isn't caused by diet alone. It's more often caused by things that make your body lose potassium, such as diarrhea, vomiting, kidney disease or certain medications [1]. People with digestive conditions like Crohn's disease or ulcerative colitis, and people who use laxatives or certain diuretics, are more likely to run low [1].

Potassium also fits into a bigger picture. Decades of micronutrient research emphasize pairing a comprehensive supplement with a low-fat, high-fiber diet [4]. Potassium-rich foods, such as fruits, vegetables and beans, are exactly the foods that make up that kind of diet. Potassium does its best work as part of the team, not by itself.

How does potassium support immune function?

Potassium supports immune function at the level of the cell. T cells use special potassium channels to set the electrical charge across their outer membrane. That charge keeps calcium flowing into the cell, which is the signal T cells need to activate and multiply when they meet a threat [2] [3].

Think of your immune system as having two jobs: responding strongly when a threat shows up, and calming back down once the job is done. Let's look at how potassium fits in.

• Switching T cells on: When a T cell recognizes a threat, its potassium channels help keep the electrical conditions right for calcium to keep flowing in. Without that, the T cell can't fully activate [2] [3].
• Helping T cells move and connect: These same channels help T cells stick to other cells and move to where they're needed [2].
• Keeping the response in check: Because these channels are so important to T-cell activity, scientists are studying ways to dial them down in autoimmune conditions, where the immune system overreacts [2].

One honest note: this happens inside your cells, and your body keeps the potassium in your blood within a narrow range [1]. There's no evidence that eating extra potassium boosts your immune system. Potassium's role in immunity is one more reason to keep your everyday intake where it should be.

Getting the most from potassium

Potassium is different from the other nutrients on this site, because food is where nearly all of it comes from. Here are four things the research points to.

• Look to your plate, not your pill: Most supplements contain 99 mg of potassium or less, a tiny fraction of what you need each day [1]. The Micro Daily EMF formula doesn't include potassium at all [5], so fruits, vegetables, beans and dairy are your main sources.
• Think beyond bananas: A medium banana has about 422 mg. Half a cup of dried apricots has about 755 mg, and a cup of cooked lentils about 731 mg [1].
• Pair more potassium with less sodium: The blood pressure benefits of potassium-rich diets are strongest when sodium is lower, too [1].
• Build your plate around whole foods: A diet rich in fruits, vegetables and beans is the same low-fat, high-fiber pattern that research pairs with a comprehensive micronutrient formula [4].

One last thing to keep in mind: potassium from food hasn't been shown to cause harm in healthy people [1]. But if you have kidney disease, or take certain blood pressure or heart medicines, too much potassium can build up in your blood. That includes potassium from supplements and salt substitutes, which are often made with potassium chloride [1]. Talk with your healthcare provider before using either.

Frequently asked questions about potassium

How much potassium do I need each day?

Adult men need 3,400 mg a day and adult women need 2,600 mg. During pregnancy that rises to 2,900 mg, and while breastfeeding to 2,800 mg. Teen boys need 3,000 mg and teen girls 2,300 mg, and younger children need 2,000 to 2,500 mg depending on age [1]. No upper limit has been set for potassium from food, because it hasn't been shown to cause harm in healthy people [1].

What foods are high in potassium?

Half a cup of dried apricots has about 755 mg, a cup of cooked lentils about 731 mg, and a cup of acorn squash about 644 mg. Half a cup of prunes or raisins gives you about 618 to 635 mg, a cup of orange juice about 496 mg, and a medium banana about 422 mg [1].

Do bananas have the most potassium?

No. Bananas are a good source, but plenty of everyday foods have more, including dried apricots, lentils, acorn squash, prunes and raisins [1].

Who is most likely to be low in potassium?

The groups most at risk are people with digestive conditions such as Crohn's disease or ulcerative colitis, and people who use laxatives or certain diuretics. Anyone with ongoing diarrhea or vomiting can also lose potassium quickly [1].

What happens if you don't get enough potassium?

Over time, a low potassium diet can raise your blood pressure, reduce the calcium in your bones and raise your risk of kidney stones [1]. Very low blood potassium, usually caused by illness or medications, can affect your muscles and heart rhythm and needs medical care.

Can you get too much potassium?

From food, not usually, if your kidneys are healthy. But people with kidney disease, or who take certain medicines for blood pressure or heart failure, such as ACE inhibitors or potassium-sparing diuretics, can build up too much. That's called hyperkalemia [1]. If that's you, ask your healthcare provider how much potassium is right for you.

Explore more micronutrients

Potassium works alongside other nutrients. Magnesium helps move potassium in and out of your cells, and calcium works with it in your muscles and nerves. Learn more about vitamin D, iron, vitamin B12, zinc and folate.

Key sources: NIH Office of Dietary Supplements, Potassium Fact Sheets for Health Professionals and Consumers [1]; Chandy KG, et al., "K+ Channels as Targets for Specific Immunomodulation," Trends in Pharmacological Sciences, 2004 [2]; Prasad KN, Micronutrients in Health and Disease, CRC Press, 2019 [4]. Every numbered citation links to its full entry on our References page.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Talk with your healthcare provider before starting any supplement, especially if you are pregnant, nursing, taking medication or have a medical condition.