What Is Potassium?

Potassium is an essential mineral that is critical to many body functions, including the delivery of nerve signals, contraction of muscles, regulation of heartbeats and blood pressure, movement of nutrients into cells, and removal of cellular waste.

How much potassium is needed per day can differ depending on the individual. The recommended daily intake for the average adult is 4700 milligrams (mg), although doses of 1600 to 2000 mg a day may be adequate for some adults.

You can usually get enough potassium from your diet but may need to take supplements if you have malnutrition or have lost too much potassium due to illness or certain medications (like diuretics). Fruits, vegetables, legumes, and seeds are rich sources of potassium. Potassium deficiency is rare.

This article describes the most common reasons for potassium supplementation, the recommended dosage by age and biological sex, and the possible side effects.  

Uses of Potassium

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or doctor. No supplement is intended to treat, cure, or prevent disease. 

Some studies suggest that higher intakes of potassium may reduce the risk of diseases like high blood pressure and stroke, osteoporosis, kidney stones, and diabetes. Some of these claims are better supported by research than others.

Blood Pressure and Stroke

Because of potassium's relationship to sodium, which regulates fluid and plasma volume, some research has focused on its ability to lower blood pressure and stroke risk.

In an older but memorable 2006 clinical trial, Dietary Approaches to Reduce Hypertension (DASH), published in the New England Journal of Medicine, researchers evaluated whether a diet rich in fruits, vegetables, low-fat dairy foods, and reduced saturated and total fat could lower blood pressure.

Many people came to call it "the DASH diet," an eating pattern that is higher in potassium and lower in sodium. Researchers fed participants a controlled diet for three weeks. Then they randomized people into a standard American diet (control), a fruit and vegetable diet, or a combination diet (the DASH diet) for eight weeks.

Those on the DASH diet lowered their systolic blood pressure (pressure when blood is ejected into arteries) by an average of 5.5 mmHg and diastolic blood pressure (pressure in arteries between beats) by 3.0 mmHg.

More recently, a 2017 study published in the International Journal of Cardiology evaluated the effect of potassium supplements on hypertension (high blood pressure). The systematic review and meta-analysis found that potassium supplementation decreased systolic blood pressure by 4.48 mmHg and diastolic blood pressure by 2.96 mmHg.

In addition, a 2013 review in the British Medical Journal evaluated whether increased potassium intake could affect heart disease risk factors and disease, including stroke. Researchers looked at 22 randomized controlled trials and 11 cohort studies. In addition to reduced blood pressure, researchers found that increased potassium intake was associated with a lower risk of stroke, with higher intakes reducing stroke risk by 24%.

Bone Density

Since potassium is alkaline (meaning it neutralizes acids), some scientists have evaluated whether consumption of potassium-rich foods and supplements could reduce the net acid content in a person's diet and preserve calcium in bones.

However, research on this subject is mixed. An older 2008 study in the American Journal of Clinical Nutrition measured the effects of potassium citrate supplementation and increased fruit and vegetable consumption in 276 postmenopausal people. It found that after two years of potassium citrate supplementation, bone turnover was not reduced, and there was no increase in bone mineral density.

By contrast, a more recent 2018 study published in Nutrients evaluated whether potassium could decrease bone loss in women with osteopenia (low bone density). The randomized, double-blind, placebo-controlled, parallel-group study included 310 postmenopausal participants.

It found that potassium citrate supplementation improved the beneficial effects of calcium and vitamin D in osteopenic women with a potassium deficit. This study suggests that potassium’s ability to increase bone mineral density may rely on the intake of calcium and vitamin D, nutrients essential for bone health. However, more research is needed to confirm or disprove this relationship.

Kidney Stones

Abnormally high urinary calcium (hypercalciuria) increases the risk of developing kidney stones. In addition, diets that are high in protein and low in potassium may contribute to increased stone formation. Therefore, some studies have examined whether potassium could reduce kidney stone risk.

In a 2016 study published in the Clinical Journal of the American Society of Nephrology, researchers examined the relationship between protein and potassium intake on kidney stones. They found that higher dietary potassium was associated with a statistically significant and considerable reduction in kidney stone risk in all groups. They also found that the type of protein consumed may also affect kidney stone risk—specifically, vegetable protein reduced risk compared to animal protein.

In addition, a 2015 review in Cochrane evaluated the role of citrate salts (such as potassium citrate) in preventing and containing calcium-containing kidney stones. In seven studies with 477 participants, researchers found that citrate significantly reduced stone size compared to placebo or no intervention. In addition, new stone formation was significantly lower in the citrate group than in the control group.

Blood Glucose and Diabetes

Since potassium is needed for insulin secretion from the pancreas, some research has focused on its relationship to glucose (blood sugar) levels and diabetes.

For example, a 2015 study evaluated the impact of potassium on glucose levels in older adults. Researchers found a significant association between lower dietary potassium intake, reduced insulin sensitivity, and increases in insulin secretion.

Similarly, a 2016 clinical trial evaluated potassium levels with glucose and diabetes risk over eight years. Researchers found that compared to those with higher potassium levels (≥4.5mmol/L), those with lower levels (<4.0mmol/L) had significantly higher fasting glucose.

In addition, researchers found an inverse association between serum and dietary potassium and diabetes risk.

Potassium Deficiency

Some people may develop a potassium deficiency when intakes are lower over time than recommended levels, they have a specific risk factor for lower than normal levels, or there is a particular reason they are unable to digest or absorb potassium.

What Causes a Potassium Deficiency?

Intakes that are less than the recommended amounts may result in potassium deficiency. When intakes are lower than your body needs, it can lead to health complications, including increased blood pressure and the risk of developing kidney stones.

In addition to low dietary intakes, some other things may contribute to potassium deficiency, including:

• Diarrhea
• Vomiting
• Diuretic use
• Laxative overuse
• Pica (eating non-nutritive substances, like clay)
• Heavy sweating
• Dialysis (a medical procedure to cycle blood when kidneys can not)
• Inflammatory bowel disease (IBD)
  

Some people are more at risk of developing a potassium deficiency, including:

• Those with IBD
• Those who take diuretics or laxatives
• People with pica

How Do I Know If I Have a Potassium Deficiency?

You may not even know if you have a mild potassium deficiency. However, more severe deficiency can result in hypokalemia, when blood serum levels fall below 3.6 mmol/L. Mild hypokalemia may produce symptoms such as:

• Constipation
• Fatigue
• Muscle weakness
• Malaise (overall feeling unwell)

More serious hypokalemia may produce the following symptoms:

• Polyuria (excessive urination)
• Encephalopathy (disease affecting brain function) in people with kidney disease
• Glucose intolerance
• Muscular paralysis
• Poor respiration
• Cardiac arrhythmias (irregular heartbeat)

Severe hypokalemia is life-threatening due to its effect on the heart and breathing. Fortunately, severe cases rarely occur because of inadequate potassium intake alone. However, if you notice any of these symptoms, it's best to have them evaluated.

What Are the Side Effects of Potassium?

Your provider may recommend you take potassium for deficiency or to lower your risk of some health conditions, like kidney stones. However, consuming a supplement like potassium may have potential side effects. These side effects may be common or severe. 

If you're increasing your intake of fruits and vegetables, you will be increasing your intake of potassium and fiber. When increasing fiber, it's essential to do so slowly and gradually to prevent gas and bloating. In addition, make sure to drink adequate amounts of fluids. Neglecting to hydrate appropriately can result in constipation.

Common Side Effects

Common side effects of potassium supplementation include:

• Diarrhea
• Nausea
• Stomach pain or discomfort or mild gas
• Vomiting

Severe Side Effects

More rarely, potassium supplements can result in severe side effects. These most often occur in people who have high intakes and impaired kidney function or who take certain medications like ACE inhibitors and potassium-sparing diuretics.

Severe side effects include:

• Confusion
• Cold, pale, or gray skin
• Stomach pain or bulging
• Black stools
• Numbness or tingling in the hands, feet, or lips
• Unexplained anxiety
• Unusual tiredness or weakness
• Weakness or heaviness in the legs

Call your healthcare provider as soon as possible if you experience severe side effects.

Precautions

People with certain health conditions or taking some medications are at greater risk of severe side effects and drug interactions from potassium. This includes individuals with abnormal kidney function and those on potassium-sparing medications or ACE inhibitors, typically used for treating high blood pressure. A complete list of medication interactions is included below.

Dosage: How Much Potassium Per Day

The National Academies of Sciences, Engineering, and Medicine (NASEM) recommends the following adequate intakes (AIs) for potassium:

• 400 mg (infants through 6 months)
• 860 mg/day (infants 7-12 months)
• 2,000 mg/day (1-3 years)
• 2,300 mg/day (4-8 years)
• 2,500 mg/day (males 9-13 years)
• 2,300 mg/day (females 9-13 years)
• 3,000 mg/day (males 14-18 years)
• 2,300 mg/day (females 14-18 years)
• 3,400 mg/day (males 19+ years)
• 2,600 mg/day (females 19+ years)
• 2,600 (under 18) or 2,900 (18+ years) during pregnancy
• 2,500 (under 18) or 2,800 (18+ years) during lactation

What Happens If I Take Too Much Potassium?

To avoid toxicity, be aware of the appropriate dosage (above). NASEM has not established an upper limit for potassium. However, people with impaired urinary potassium excretion due to health conditions like kidney disease or certain medications should be aware of potassium supplementation's potential toxicity.

If you fall into these categories and consume more potassium than your healthcare provider recommends, you may want to seek medical attention. In addition, if you notice any of the severe side effects (above), seek emergency medical care.

Interactions

Some medications can interact with potassium supplements. These include:

• ACE inhibitors
• Angiotensin receptor blockers (ARBs)
• Potassium-sparing diuretics, such as Midamor (amiloride) and Aldactone (spironolactone)
• Loop diuretics, such as Lasix (furosemide) and Bumex (bumetanide)
• Thiazide diuretics, such as Diuril (chlorothiazide) and Zaroxolyn (metolazone)

These medications can impact potassium in dangerous ways. Therefore, experts recommend monitoring potassium levels in people who take these drugs.

It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients are included and in what amounts. In addition, please review the supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications. 

How To Store Potassium

Store fresh fruits and vegetables using best practices for maximizing their freshness. Storage guidelines differ depending on the fruit or vegetable. For example, some should be refrigerated while others, such as tomatoes, should be left at room temperature.

Store potassium supplements in a cool, dry place. Keep potassium away from direct sunlight. Discard after one year or as indicated on the packaging.

Sources of Potassium and What To Look For

The optimal way to meet your potassium needs is to eat a variety of whole foods, including fruits like avocados, oranges, bananas, vegetables (such as sweet potatoes, squash, and dried beans), low-fat milk, and certain sources of protein like salmon and chicken. That's because foods meet other nutritional needs and are usually absorbed more readily by the body.

When you cannot meet adequate food intake, supplements are also an option.

Foods Sources of Potassium

According to the USDA nutrition database, the following are foods high in potassium:

• Acorn squash (1 cup cooked without salt): 896 milligrams
• Apple (1 medium with skin): 195 milligrams
• Artichokes (1 cup hearts cooked): 480 milligrams
• Avocado (1/4 of the whole): 172 milligrams
• Banana (1 medium): 430 milligrams
• Beets (1 cup raw): 442 milligrams
• Broccoli (1 cup chopped and cooked): 457 milligrams
• Baby Brussels sprouts (13 pieces): 315 milligrams
• Beans (1/2 cup dried—amounts vary based on variety): 1,813 milligrams
• Cantaloupe (1 cup cubes): 427 milligrams
• Carrots (1 cup chopped): 410 milligrams
• Cherries (1 cup without pits): 342 milligrams
• Milk (1 cup low-fat): 350-380 milligrams
• Mushrooms (1 cup whole): 305 milligrams
• Orange (1 small): 238 milligrams
• Peas (1 cup raw): 354 milligrams
• Peppers (1 cup chopped): 314 milligrams
• Parsley (1 cup chopped): 332 milligrams
• Potato (1 medium baked with skin): 930 milligrams
• Quinoa (1 cup cooked): 318 milligrams
• Salmon (6 ounces): 730 milligrams
• Spinach (1 cup cooked): 839 milligrams
• Sweet potato (1 cup baked ): 664 milligrams
• Tomatoes (1 cup chopped): 430 milligrams
• Watermelon (1 cup diced): 170 milligrams
• Yogurt (1 cup): 625 milligrams

If you've had difficulty adding fresh produce to your diet, consider adding frozen fruits and vegetables. Food is frozen at peak freshness, enhancing its nutritional value. Avoid cooking at high heat or boiling your fruits and vegetables to preserve vitamin content. If you like, you can eat certain fruits and vegetables raw. Otherwise, sauté them on medium heat with a small amount of fat, such as olive or coconut oil.

Some processed and packaged foods also contain added potassium salts or naturally occurring potassium (such as dried beans and whole grains). These foods include:

• Cereals
• Snack foods
• Frozen foods
• Processed meat
• Soups
• Sauces
• Meal bars

Keep in mind that some packaged and canned foods can be very high in sodium, making these not the best choice for someone who is thinking of using potassium to lower blood pressure.

If you must monitor your potassium intake, be mindful of the labels. Most ingredient labels will list "potassium chloride" as an additive.

Supplementing With Potassium

Potassium supplements come in capsules, tablets, liquid, and powder. Common potassium supplements include:

• Potassium chloride
• Potassium citrate
• Potassium phosphate
• Potassium aspartate
• Potassium bicarbonate
• Potassium gluconate

Research has shown that none of these forms is better than another. You may also find added potassium in products such as Emergen C (a powdered drink).

Most OTC potassium supplements and multivitamin-mineral supplements provide no more than about 99 mg of potassium per serving (which is a small percentage of the recommended intake). In the past, the FDA ruled that some oral drug products that contain potassium chloride and provide more than 99 mg of potassium are not safe because they have been associated with small-bowel lesions. As a result, the FDA requires a warning label about the potential for these lesions on some potassium salts that exceed 99 mg.

Be sure to read the labels of potassium products carefully, especially if you're at risk for hyperkalemia. Also, if you are vegan or have allergies, read labels carefully for vegan or allergen-free products.

Summary

Potassium is a mineral that supports many body functions, including the heart and blood vessels, nerves, and muscles. There is evidence that potassium may reduce the risk of high blood pressure, stroke, diabetes, and kidney stones.

People with kidney disease are at risk of potassium toxicity because their kidneys may not filter out potassium adequately. Therefore, they should not take potassium supplements unless directed by a healthcare provider. In addition, certain medications, including ACE inhibitors, diuretics, and some others, may also pose a risk. So, talking to a healthcare provider before taking any supplement, including potassium, is essential.