Potassium is a mineral that helps the kidneys function normally. It also plays a key role in cardiac, skeletal, and smooth muscle contraction, making it an important nutrient for normal heart, digestive, and muscular function. A diet high in potassium from fruits, vegetables, and legumes is generally recommended for optimum heart health. 

Having too much potassium in the blood is called hyperkalemia and having too little in the blood is known as hypokalemia. Proper balance of potassium in the body depends on sodium. Therefore, excessive use of sodium may deplete the body's stores of potassium. Other conditions that can cause potassium deficiency include diarrhea, vomiting, excessive sweating, malnutrition, and use of diuretics. In addition, coffee and alcohol can increase the amount of potassium excreted in the urine. Adequate amounts of magnesium are also needed to maintain normal levels of potassium.

For most people, a healthy diet rich in vegetables and fruits provides all of the potassium needed. The elderly are at high risk for developing hyperkalemia due to decreased kidney function that often occurs as one ages. Older people should be careful when taking medication that may further affect potassium levels in the body, such as nonsteroidal anti-inflammatories (NSAIDs) and ACE inhibitors (see section on Interactions for additional information). Taking potassium supplements, at any age, should only be done under the guidance of a healthcare provider.

Hypokalemia
The most important use of potassium is to treat the symptoms of hypokalemia, which include weakness, lack of energy, muscle cramps, stomach disturbances, an irregular heartbeat, and an abnormal EKG (electrocardiogram, a test that measures heart function). Treatment of this condition takes place under the guidance and direction of a physician.

Osteoporosis
High dietary intake of potassium from fruits and vegetables throughout one's life helps to preserve bone mass thereby preventing bone loss that can lead to osteoporosis.

High Blood Pressure
Some studies have linked low dietary potassium intake with high blood pressure. The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends adequate amounts of potassium in the diet, along with other measures such as dietary calcium and weight loss, to prevent the development of high blood pressure. Similarly, the Dietary Approaches to Stop Hypertension (DASH) diet emphasizes eating foods rich in fruits, vegetables, and low- or non-fat dairy products to provide high intake of potassium, as well as magnesium and calcium.

While appropriate and adequate dietary intake is necessary for preventing or improving blood pressure, potassium supplements are probably not. Some animal and early human studies did suggest that potassium supplements could help to lower blood pressure. More recent well-designed studies, however, suggest that potassium supplements do not improve blood pressure significantly. Use of potassium supplements for blood pressure, therefore, depends on the medications you are taking and the instructions of your doctor.

Stroke
In several population based studies evaluating very large groups of men and women over time, a diet rich in potassium was associated with a reduced risk of stroke. For the men, this seems to be particularly true among those with high blood pressure and/or those taking diuretics (blood pressure medications that help the kidneys eliminate sodium and water from the body). Potassium supplements, however, do not seem reduce the risk of stroke.

Inflammatory Bowel Disease (IBD)
Amongst other nutrient deficiencies, people with IBD (namely, ulcerative colitis or Crohn's disease) often have low levels of potassium. Your doctor will determine if supplementation with potassium is necessary.

Asthma
Several studies have suggested that diets low in potassium are associated with poor lung function and even asthma in children compared to those who eat normal amounts of potassium. Enhancing dietary intake of potassium through foods such as fish, fruits, and vegetables may, therefore, prove to be of value for preventing or treating asthma.

The best dietary sources of potassium are fresh unprocessed foods, including meats, fish, vegetables (especially potatoes), fruits (especially avocados, dried apricots, and bananas), citrus juices (such as orange juice), dairy products, and whole grains. Most potassium needs can be met by eating a varied diet with adequate intake of milk, meats, cereals, vegetables, and fruits.

There are several potassium supplements on the market, including potassium acetate, potassium bicarbonate, potassium citrate, potassium chloride, and potassium gluconate.

Potassium can also be found in multivitamins.

Potassium supplements, other than the small amount included in a multivitamin, should only be taken under the specific guidance and instruction of a healthcare provider. This is particularly true for children.

The recommended daily intakes of dietary potassium are listed below:

Pediatric

• Infants birth to 6 months: 500 mg or 13 mEq
• Infants 7 months to 12 months: 700 mg or 18 mEq
• Children 1 year: 1000 mg or 26 mEq
• Children 2 to 5 years: 1400 mg or 36 mEq
• Children 6 to 9 years: 1600 mg or 41 mEq
• Children over 10 years: 2000 mg or 51 mEq

Adult

• 2000 mg or 51 Meq, including for pregnant and nursing women.

Because of the potential for side effects and interactions with medications, dietary supplements should be taken only under the supervision of a knowledgeable healthcare provider. In the case of potassium, this is particularly important in the elderly.

Diarrhea and nausea are two common side effects from potassium supplements. Other potential adverse effects include muscle weakness, slowed heart rate, and abnormal heart rhythm.

Excessive amounts of the herb licorice (not licorice candy) and caffeine-containing herbs (such as cola nut, guarana, and possible green and black tea) can lead to loss of potassium.

Potassium must not be used by people with hyperkalemia.

If you are currently being treated with any of the following medications, you should not use potassium without first talking to your healthcare provider.

Potassium levels may be increased by the following medications:

• Nonsteroidal anti-inflammatory drugs (NSAIDs; such as ibuprofen, piroxicam, and sulindac): This interaction is particularly likely to occur in people with decreased kidney function.
• ACE inhibitors (such as captopril, enalapril, and lisinopril): This interaction is particularly likely to occur in people who are taking NSAIDs, potassium-sparing diuretics (such as spironolactone, triamterene, or amiloride), or salt substitutes along with the ACE inhibitor. A rise in potassium from ACE inhibitors may also be more likely in people with decreased kidney function and diabetes.
• Heparin (used for blood clots)
• Cyclosporine (used following a transplant to suppress the immune system)
• Trimethoprim (an antibiotic)
• Beta-blockers (such as metoprolol and propranolol that are used to treat high blood pressure)

Potassium levels may be decreased by the following medications:

• Thiazide diuretics (such as hydrochlorothiazide)
• Loop diuretics (such as furosemide and bumetanide)
• Corticosteroids 
• Amphotericin B 
• Antacids 
• Insulin 
• Theophylline (used for asthma)
• Laxatives 

Please refer to the depletions monographs related to these medications for additional information. A healthcare practitioner will determine whether potassium supplements are needed when individuals are taking these medications.

Other potential interactions include:

• Digoxin: Low blood levels of potassium increase the likelihood of toxic effects from digoxin, a medication used to treat abnormal heart rhythms. Normal levels of potassium should be maintained during digoxin treatment which will be measured and directed by the healthcare provider.

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