Home  >  Health Resources  >  Health Encyclopedia

Potassium

Potassium

Other name(s):

KCl, potassium chloride

General description

Potassium is a reactive, metallic element. It’s found in nature as a "salt". It comes as potassium chloride or potassium nitrate. It plays a major role in making nerve signals that are needed for skeletal smooth muscle and heart muscle contractions.

It helps keep normal blood pressure. It’s also needed for keeping electrolyte and pH balance (the acidity of the blood and other bodily fluids).

Most potassium in our body is found in muscle and lean tissue cells. Potassium is in most foods. It’s readily absorbed by the body.

Potassium salts are water soluble. It’s found in solution as a positively charged particle (cation). Potassium is the major cation inside living cells.

We need potassium to keep the electrochemical balance across cell membranes. This is crucial in conducting nerve signals. This leads to skeletal muscle contraction, hormone release, and smooth muscle and heart contraction.

Potassium levels are controlled in the kidneys by a hormone called aldosterone.

Medically valid uses

Potassium reduces high blood pressure (hypertension).

A diet rich in fruits, vegetables, and high-potassium, low-fat dairy products has been shown to decrease blood pressure and decrease calcium excretion. But potassium supplements aren’t usually recommended. This is because they can cause side effects, such as cardia arrest.

Unsubstantiated claims

Please note that this section reports on claims that have not yet been substantiated through studies.

Research in animals shows that potassium may prevent strokes. It may also prevent kidney damage due to high blood pressure. However, these effects in humans aren’t known.

Recommended intake

There is no Recommended Dietary Allowance (RDA) for potassium. The daily Adequate Intake (AI) has been set based off the average intake of healthy people. It’s given in grams per day.

Age Group

AI (g/d)

Infants (0 to 6 months)

0.4

Infants (7 to 12 months)

0.7

Children (1 to 3 years)

3.0

Children (4 to 8 years)

3.8

Children (9 to 13 years)

4.5

Adolescents and Adults (14+ years)

4.7

Pregnancy

4.7

Lactation

5.1

Potassium comes as an oral liquid and tablet.

It’s widely available in foods. This is because it’s a main component of living cells. Good sources include vegetables and fruits, such as bananas, citrus fruits, and tomatoes. They also include milk and yogurt, and fresh meats. The following table lists the potassium content of some food sources.

Food

Potassium content

Tomato paste (1 cup)

1,221 mg

Avocado (1 medium)

1,097 mg

Potato, baked w/ skin (1 potato)

844 mg

Navy beans (1 cup, boiled)

669 mg

Prunes, dried (10 prunes)

626 mg

Dates, dried (10 dates)

541 mg

Cantaloupe, raw (1 cup pieces)

494 mg

Honeydew, raw (1 cup pieces)

461 mg

Banana, raw (1 medium)

451 mg

Milk, skim (8 fluid oz)

406 mg

Milk, whole (8 fluid oz)

370 mg

Yogurt (6 oz)

350 mg

Apricots, raw (3 medium)

313 mg

Nectarine, raw (1 medium)

288 mg

Tomato, raw (1 tomato)

273 mg

Orange, raw (1 medium)

250 mg

Strawberries, raw (1 cup)

247 mg

Pear, raw (1 medium)

208 mg

Peach, raw (1 medium)

171 mg

Potassium is lost during cooking. Adding potassium chloride to cooking water may keep it from leaching out into the water. Use a small amount of water when cooking vegetables. Be careful not to overcook vegetables. Steaming foods will also help retain potassium levels.

Low potassium levels (hypokalemia) can cause muscle weakness, lethargy, and irregular heart rate (arrhythmia). Low levels make it tricky for the nerves to fire signals. This gets in the way of muscle contraction. Other signs of low potassium levels include nausea, bone fragility, and enlarged adrenal gland (adrenal hypertrophy). They also include decreased growth rate, weight loss, and irrational behavior.

Deficiency doesn’t occur under normal conditions. This is because it’s in many foods. But certain issues can lead to potassium deficiency. These include the following:

  • Vomiting and diarrhea that lasts a long time

  • Water pill (diuretic) use

  • Laxative and steroid abuse

  • Anorexia

  • Chronic starvation

  • Hormone problems

If you’re taking certain water pills, your healthcare provider may give you a potassium supplement. If you’re taking more than 300 mg per day, your healthcare provider will watch you closely. High potassium leads to decreased calcium excretion. This is often a good thing.

Side effects, toxicity, and interactions

High potassium levels (hyperkalemia) are dangerous. Symptoms of too much potassium are similar to signs of low levels. These can include muscle weakness, heart rhythm issues, and cardiac arrest. Cells have trouble responding to nerve impulses with too much potassium. This affects muscle contractions.

High potassium levels can be cause by kidney problems or hormonal imbalances. They can also be due to excessive supplement use.

Crushing injuries that cause cell damage and red blood cell hemolysis can cause more potassium to go into the bloodstream. This can cause high levels of potassium. Intense exercise can also cause potassium levels to rise. But this often isn’t dangerous.

Since high potassium levels can cause cardiac arrest, supplements usually aren’t recommended. You shouldn’t take them unless your healthcare provider tells you to.

Women who are pregnant or breastfeeding should talk to their healthcare providers before taking any supplements.

Some water pills can cause low potassium levels. You shouldn’t take potassium-sparing diuretics are available with potassium supplements. If you’re taking a water pill, talk to your healthcare provider before taking any supplements.

Additional information

People may use potassium chloride as a salt replacement when trying to lower their blood pressure. It has a bitter taste. This reduces the risk of high potassium levels because the taste limits how much people use. Talk to your healthcare provider, though, before you try this. Low potassium levels may play a bigger role in high blood pressure than high levels of sodium.

 

Today's Interactive Tools