Potassium is a very important mineral for the proper function of all cells, tissues, and organs in the human body. It is also an electrolyte, a substance that conducts electricity in the body, along with sodium, chloride, calcium, and magnesium. Potassium is crucial to heart function and plays a key role in skeletal and smooth muscle contraction, making it important for normal digestive and muscular function. Many foods contain potassium, including all meats, some types of fish (such as salmon, cod, and flounder), and many fruits, vegetables, and legumes. Dairy products are also good sources of potassium.
Having too much potassium in the blood is called hyperkalemia; having too little is known as hypokalemia. Keeping the right potassium balance in the body depends on the amount of sodium and magnesium in the blood. Too much sodium -- common in Western diets that use a lot of salt -- may increase the need for potassium. Diarrhea, vomiting, excessive sweating, malnutrition, malabsorption syndromes (such as Crohn's disease) can also cause potassium deficiency, as well as use of a kind of heart medicine called loop diuretics.
Most people get all of the potassium they need from a healthy diet rich in vegetables and fruits. Older people have a greater risk of hyperkalemia because their kidneys are less efficient at eliminating potassium as they age. Older people should be careful when taking medication that may affect potassium levels, such as nonsteroidal anti-inflammatory drugs (NSAIDs) and ACE inhibitors (see section on Interactions).
Whatever your age, talk to your doctor before taking potassium supplements.
Studies show a positive link between a diet rich in potassium and bone health, particularly among elderly women, suggesting that increasing consumption of foods rich in potassium may play a role in osteoporosis prevention. More research is needed to determine whether a diet high in potassium can reduce bone turnover in people.
The most important use of potassium is to treat the symptoms of hypokalemia (low potassium), which include weakness, lack of energy, muscle cramps, stomach disturbances, an irregular heartbeat, and an abnormal EKG (electrocardiogram, a test that measures heart function). Hypokalemia is usually caused by the body losing too much potassium in the urine or intestines; it's rarely caused by a lack of potassium in the diet. Hypokalemia can be life threatening and should always be treated by a doctor.
High Blood Pressure
Some studies have linked low levels of potassium in the diet with high blood pressure. And there is some evidence that potassium supplements might cause a slight drop in blood pressure. Other studies show that increasing potassium intake reduces the risk of dying from cardiovascular disease. Researchers suspect this is largely due to potassium's blood pressure lowering effects. But not all studies agree -- 2 large studies found no effect on blood pressure. It may be that taking potassium helps lower blood pressure only if you're not getting enough of this mineral to start with. Before taking potassium or any supplement for high blood pressure, talk to your doctor.
People who get a lot of potassium in their diet have a lower risk of stroke. However, potassium supplements don't seem to produce the same benefit.
Inflammatory Bowel Disease (IBD)
People with IBD (ulcerative colitis or Crohn's disease) often have trouble absorbing nutrients from their intestine, and may have low levels of potassium and other important nutrients. If you have IBD, your doctor may check your potassium levels and recommend a supplement.
Good sources of potassium include bananas, citrus juices (such as orange juice), avocados, cantaloupes, tomatoes, potatoes, lima beans, flounder, salmon, cod, chicken, and other meats.
Several potassium supplements are on the market, including potassium acetate, potassium bicarbonate, potassium citrate, potassium chloride, and potassium gluconate. Supplements are available in tablets, capsules, effervescent tablets, powders, and liquids.
Potassium can also be found in multivitamins.
Potassium supplements, other than the small amount included in a multivitamin, should be taken only under your doctor's supervision. Do not give potassium supplements to a child unless your doctor prescribes it.
Adequate intake of potassium from dietary sources are listed below:
Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider.
Older adults should talk to their doctor before taking potassium supplements.
Side effects can include diarrhea, stomach irritation, and nausea. At higher doses, muscle weakness, slowed heart rate, and abnormal heart rhythm may occur. Contact your health care provider if you develop severe stomach pain, irregular heartbeat, chest pain, or other symptoms.
People with hyperkalemia or kidney disease should not take potassium supplements.
People who take ACE inhibitors, potassium-sparing diuretics, or the antibiotic trimethoprim and sulfamethoxazole (Bactrim, Septra) should not take potassium.
If you are being treated with any of the following medications, you should not use potassium without first talking to your health care provider.
Angiotensin Converting Enzyme (ACE) Inhibitors: These drugs, including benazepril, captopril, enalapril, fosinopril, lisinopril, moeexipril, perdinodopril, quinapril, ramipril, trandolapril, may increase the risk of hyperkaleimia.
Angiotensin Receptor Blockers: Increased risk of hyperkalemia.
Potassium Sparing Diuretics: These drugs, including amiloride, triamterene, spironolactone, may increase the risk of hyperkalemia.
Indomethacin: May increase the risk of hyperkalemia.
The following medications may cause potassium levels to rise:
The following medications may cause potassium levels to decrease:
If you are taking any of these medications, it is important for your doctor to test your potassium levels to see whether or not you need a supplement. Do not start taking a supplement on your own.
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 and heart failure. Your doctor will test your potassium levels to make sure they stay normal.
Dickinson HO, Nicolson DJ, Campbell F, Beyer FR, Mason J. Potassium supplementation for the management of primary hypertension in adults. Cochrane Database Syst Rev. 2006 Jul 19;3:CD004641. Review.
He FJ, MacGregor GA. Beneficial effects of potassium on human health. Physiol Plant. 2008;133(4):725-35.
Hermansen K. Diet, blood pressure and hypertension. Br J Nutr. 2000:83(Suppl 1):S113-119.
Houston MC. Treatment of hypertension with nutraceuticals, vitamins, antioxidants and minerals. Expert Rev Cardiovasc Ther. 2007 Jul;5(4):681-91.
Krauss RM, Eckel RH, Howard B, et al. AHA dietary guidelines. Revision 2000: A statement for healthcare professionals from the Nutrition Committee of the American Heart Association. Circulation. 2000;102:2284-2299.
Lanham-New SA. The balance of bone health: tipping the scales in favor of potassium-rich, bicarbonate-rich foods. J Nutr. 2008;138(1):172S-177S.
Matsui H, Shimosawa T, Uetake Y, Wang H, Ogura S, Kaneko T, et al. Protective effect of potassium against the hypertensive cardiac dysfunction: association with reactive oxygen species reduction. Hypertension. 2006 Aug;48(2):225-31.
Myers VH, Champagne CM. Nutritional effects on blood pressure. Curr Opin Lipidol. 2007 Feb;18(1):20-4.
Matsumura M, Nakashima A, Tofuku Y. Electrolyte disorders following massive insulin overdose in a patient with type 2 diabetes. Intern Med. 2000;39(1):55-57.
Newnham DM. Asthma medications and their potential adverse effects in the elderly: recommendations for prescribing. Drug Saf. 2001;24(14):1065-1080.
O'Shaughnessy KM. Role of diet in hypertension management. Curr Hypertens Rep. 2006 Aug;8(4):292-7. Review.
Perazella MA. Trimethoprim-induced hyperkalemia: clinical data, mechanism, prevention and management. Drug Saf. 2000;22(3):227-236.
Physicians' Desk Reference. 55th ed. Montvale, NJ: Medical Economics Co., Inc.; 2001:1418-1422, 2199-2207.
Pikilidou MI, Lasaridis AN, Sarafidis PA, Tziolas IM, Zebekakis PE, Dombros NV, Giannoulis E. Blood pressure and serum potassium levels in hypertensive patients receiving or not receiving antihypertensive treatment. Clin Exp Hypertens. 2007;29(8):563-73.
Rafferty K, Heaney RP. Nutrient effects on the calcium economy: emphasizing the potassium controversy. J Nutr. 2008;138(1):166S-171S.
Wu G, Tian H, Han K, Xi Y, Yao Y, Ma A. Potassium magnesium supplementation for four weeks improves small distal artery compliance and reduces blood pressure in patients with essential hypertension. Clin Exp Hypertens. 2006 Jul;28(5):489-97.
Zhu K, Devine A, Prince RL. The effects of high potassium consumption on bone mineral density in a prospective cohort study of elderly postmenopausal women. Osteoporos Int. 2009;20(2):335-40.
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