Potassium as a dietary supplement
Potassium is a vital mineral that plays a significant role in various bodily functions and is often promoted as a dietary supplement, particularly for its potential benefits in managing hypertension. This essential nutrient is primarily sourced from common foods such as bananas, potatoes, and fish, and is critical for maintaining electrolyte balance alongside sodium and chloride. While true potassium deficiencies are rare, the typical Western diet tends to be higher in sodium than potassium, which may necessitate supplementation for some individuals.
Potassium supplements are commonly available in various forms, with potassium chloride being the most prevalent. Therapeutically, they are often prescribed to counteract potassium depletion caused by diuretic medications, which can inadvertently lead to increased blood pressure issues. Some studies have indicated that potassium supplementation may contribute to modest blood pressure reductions, particularly in those with high salt intake.
However, safety is a major consideration, as excessive potassium can lead to complications, especially in individuals with kidney disease or those taking specific medications like potassium-sparing diuretics. Therefore, it is crucial for individuals to consult healthcare professionals before beginning potassium supplementation, particularly if they have underlying health conditions or are on certain medications.
Potassium as a dietary supplement
DEFINITION: Natural substance essential for health and promoted as a dietary supplement for specific health benefits.
- PRINCIPAL PROPOSED USE: Hypertension
Overview
Potassium is a mineral found in many foods and supplements. Pure potassium is not seen in health food stores or pharmacies because it is a highly reactive metal that bursts into flames when exposed to water. The potassium that is eaten or taken as a supplement is composed of potassium atoms bound to other nonmetallic substances.
Potassium is one of the major electrolytes in the body, along with sodium and chloride. Potassium and sodium work together like a molecular seesaw: When the level of one goes up, that of the other goes down. Together, the three dissolved minerals play an intimate chemical role in every function of the body.
Requirements and Sources
Potassium is an essential mineral obtained from many common foods. True potassium deficiencies, called hypokalemia, are rare except in cases of prolonged vomiting or diarrhea or with the use of diuretic drugs. However, in one sense, potassium deficiency is common when compared to the amount of sodium in the diet. It is probably healthy to consume a minimum of five times as much potassium as sodium (and perhaps fifty to one hundred times as much), but the standard American diet contains twice as much sodium as potassium. Therefore, taking extra potassium may help balance the excess sodium consumed.
Bananas, orange juice, potatoes, avocados, lima beans, cantaloupes, peaches, tomatoes, flounder, salmon, and cod all contain more than 300 milligrams (mg) of potassium per serving. Other good sources include chicken, meat, and various other fruits, vegetables, and fish.
Over-the-counter potassium supplements typically contain 99 mg of potassium per tablet. There is some evidence that, of the different forms of potassium supplements, potassium citrate may be most helpful for those with high blood pressure.
Some research indicates that it is also important to get enough magnesium when taking potassium, and some evidence supports also taking extra vitamin B12.
Therapeutic Dosages
When used by physicians, potassium is usually measured in milliequivalents (meqs) rather than in the more common milligrams. A typical therapeutic dosage of potassium is between 10 and 20 meq, taken three to four times daily. Potassium supplements are most commonly available in the form of potassium chloride. Other forms include potassium phosphate, citrate, aspartate, bicarbonate, and gluconate.
The National Institutes of Health recommends daily potassium intake according to age and sex—from birth to six months (400 mg), seven to twelve months (860 mg), one to three years (2,000 mg), and four to eight years (2,300 mg). Boys continue to require 2,300 mg per day from age nine to eighteen and 2,600 mg per day from age nineteen. Girls ages nine to thirteen require 2,500 mg, ages fourteen to eighteen 3,000 mg, and over age nineteen, 3,400 mg. Pregnant girls (under eighteen) require 2,600 mg, while pregnant women require 2,900 mg. Lactating girls require 2,500 mg while lactating women require 2,800 mg.
Therapeutic Uses
The most common use of potassium supplements is to make up for potassium depletion caused by diuretic drugs. These medications are often used to help regulate blood pressure, but by depleting the body of potassium, they may inadvertently make blood pressure harder to control.
There is limited evidence for proposed uses like controlling gout and high blood pressure and limiting kidney stones, heart disease, and stroke.
Scientific Evidence
High blood pressure. According to a review of thirty-three double-blind studies, potassium supplements can produce a slight but definite drop in blood pressure. However, two large studies found no benefit. The explanation is probably that potassium is only slightly helpful. When a treatment has only a small effect, it is not unusual for some studies to show no effect while others find a modest benefit. Potassium may help only those people who are deficient in this mineral. Evidence suggests that potassium supplements may be most effective for people who eat too much salt. For this reason, the American Heart Association recommends individuals trying to control their blood pressure should ingest 3,500 mg to 5,000 mg of potassium.
Kidney problems. Prescription potassium citrate is used to treat a kidney condition called renal tubular acidosis because it is a urinary alkalinizer. Insufficient evidence exists to confirm its proposed use as a preventative aid or treatment for kidney stones.
Safety Issues
As an essential nutrient, potassium is safe when taken at appropriate dosages. If too much is taken, the body will simply excrete it in the urine. However, people who have severe kidney disease cannot excrete potassium normally and should consult a physician before taking a potassium supplement. Similarly, persons taking potassium-sparing diuretics (such as spironolactone), ACE inhibitors (such as captopril), or trimethoprim-sulfamethoxazole should not also take potassium supplements except under doctor supervision. Potassium pills can cause injury to the esophagus if they get stuck on the way down, so one should make sure to take them with plenty of water.
Important Interactions
Persons taking loop diuretics or thiazide diuretics may need more potassium. Persons taking ACE inhibitors (such as captopril, lisinopril, and enalapril), potassium-sparing diuretics (such as triamterene or spironolactone), or trimethoprim-sulfamethoxazole should not take potassium except on the advice of a physician.
Bibliography
Gu, D., et al. “Effect of Potassium Supplementation on Blood Pressure in Chinese.” Journal of Hypertension, vol. 19, 2001, pp. 1325-31.
He, F. J., et al. “Effects of Potassium Chloride and Potassium Bicarbonate on Endothelial Function, Cardiovascular Risk Factors, and Bone Turnover in Mild Hypertensives.” Hypertension, vol. 55, 2010, pp. 681-88.
“Potassium.” National Institutes of Health, 2 June 2022, ods.od.nih.gov/factsheets/Potassium-HealthProfessional. Accessed 20 Sept. 2024.
"Potassium - Uses, Side Effects, and More." WebMD, www.webmd.com/vitamins/ai/ingredientmono-851/potassium. Accessed 20 Sept. 2024.
Savica, V., G. Bellinghieri, and J. D. Kopple. “The Effect of Nutrition on Blood Pressure.” Annual Review of Nutrition, vol. 30, 2010, 365-401.