Potassium

What does it do? Potassium is needed to regulate water balance, levels of acidity, blood pressure, and neuromuscular function. This mineral also plays a critical role in the transmission of electrical impulses in the heart. People with low blood levels of potassium who are undergoing heart surgery are at an increased risk of developing heart arrhythmias and an increased need for cardiopulmonary resuscitation.1 Potassium is also required for carbohydrate and protein metabolism.

Where is it found? Most fruits are excellent sources of potassium. Beans, milk, and vegetables contain significant amounts of potassium.

Potassium has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating Health Concerns
3Stars High blood pressure (for people not taking potassium-sparing diuretics)
Kidney stones (citrate in combination with magnesium citrate)
2Stars Cardiac arrhythmia
Congestive heart failure
Premenstrual syndrome
Stroke
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

Who is likely to be deficient? So-called primitive diets provided much greater levels of potassium than modern diets, which may provide too little. Gross deficiencies, however, are rare except in cases of prolonged vomiting, diarrhea, or use of “potassium-depleting” diuretic drugs. People taking one of these drugs are often advised by their doctor to take supplemental potassium. Prescription amounts of potassium provide more than the amounts sold over the counter but not more than the amount found in several pieces of fruit.

How much is usually taken? The best way to obtain extra potassium is to eat several pieces of fruit per day, as well as liberal amounts of vegetables. The amount of potassium found in the diet ranges from about 2.5 grams to about 5.8 grams per day. The amount allowed in supplements—99 mg per tablet or capsule—is very low, considering that one banana can contain 500 mg. One should not attempt to achieve higher potassium levels by taking large numbers of potassium pills. This concentrated form of potassium can irritate the stomach—a problem not encountered with the potassium in food.

Are there any side effects or interactions? High potassium intake (several hundred milligrams at one time in tablet form) can produce stomach irritation. People using potassium-sparing drugs should avoid using potassium chloride-containing products, such as Morton Salt Substitute®, No Salt®, Lite Salt®, and others and should not take potassium supplements, except under the supervision of a doctor. Even eating several pieces of fruit each day can sometimes cause problems for people taking potassium-sparing drugs, due to the high potassium content of fruit.

Potassium and sodium work together in the body to maintain muscle tone, blood pressure, water balance, and other functions. Many researchers believe that part of the blood pressure problem caused by too much salt (which contains sodium) is made worse by too little dietary potassium.

People with kidney failure should not take potassium supplements, except under careful medical supervision.

Are there any drug interactions? Certain medications may interact with potassium. Refer to the drug interactions safety check for a list of those medications.

References:

1. Wahr JA, Parks R, Boisvert D, et al. Preoperative serum potassium levels and perioperative outcomes in cardiac surgery patients. JAMA 1999;281:2203–10.