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 disease, can also cause potassium deficiency. Use of a kind of heart medicine called loop diuretics can also cause you to be short on potassium.
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 non-steroidal anti-inflammatory drugs (NSAIDs) and ACE inhibitors.
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. This suggests that increasing consumption of foods rich in potassium may play a role in preventing osteoporosis. 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 usually happens when the body loses too much potassium in the urine or intestines. It is 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. There is also evidence that potassium supplements might cause a slight drop in blood pressure. Other studies suggest that increasing potassium intake reduces the risk of dying from cardiovascular disease, possibly because of potassium's blood pressure lowering effects. Not all studies agree. Two large studies found no effect on blood pressure. It may be that taking potassium helps lower blood pressure only if you are deficient in the mineral. Before taking potassium or any supplement for high blood pressure, talk to your doctor.
Studies show that people with a higher sodium-potassium ratio have a higher risk of heart disease and all-cause mortality. Other studies show that heart attack patients who have moderate potassium levels, between 3.5 and 4.5 mEq/L, have a lower risk of death.
People who get a lot of potassium in their diet have a lower risk of stroke, especially ischemic stroke. However, potassium supplements do not seem to produce the same benefit.
Inflammatory Bowel Disease (IBD)
People with IBD (ulcerative colitis or Crohn disease) often have trouble absorbing nutrients from their intestines, 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.
How to Take It
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 as follows:
- Infants, birth to 6 months: 400 mg/day
- Infants, 7 months to 12 months: 700 mg/day
- Children, 1 to 3 years: 3 grams (3,000 mg)/day
- Children, 4 to 8 years: 3.8 grams (3,800 mg)/day
- Children, 9 to 13 years: 4.5 grams (4,500 mg)/day
- Adults, 19 years and older: 4.7 grams (4,700 mg)/day
- Pregnant women: 4.7 grams (4,700 mg)/day
- Breastfeeding women: 5.1 grams (5,100 mg)/day
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 doctors 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 doctor 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 a trimethoprim-sulfamethoxazole antibiotic (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 may increase the risk of hyperkalemia, including benazepril, captopril, enalapril, fosinopril, lisinopril, moeexipril, perdinodopril, quinapril, ramipril, trandolapril.
Angiotensin Receptor Blockers: May increase the risk of hyperkalemia.
Potassium Sparing Diuretics: May increase the risk of hyperkalemia, including amiloride, triamterene, and spironolactone.
Indomethacin: May increase the risk of hyperkalemia.
The following medications may cause potassium levels to rise
Nonsteroidal anti-inflammatory drugs (NSAIDs): People who have poor kidney function and take NSAIDs are at higher risk.
ACE inhibitors: These drugs treat high blood pressure, heart disease, diabetes, some chronic kidney diseases, migraines, and scleroderma. People who take ACE inhibitors and NSAIDs, potassium-sparing diuretics, or salt substitutes may be particularly vulnerable to hyperkalemia. A rise in potassium from ACE inhibitors may also be more likely in people with poor kidney function and diabetes. ACE inhibitors include:
- Benazepril (Lotensin)
- Captopril (Capoten)
- Enlapril (Vasotec)
- Fosinopril (Monopril)
- Lisinopril (Zestril)
- Moexipril (Univasc)
- Peridopril (Aceon)
- Ramipril (Altace)
- Trandolapril (Mavik)
Beta-blockers: Used to treat high blood pressure, glaucoma, migraines, includes:
- Atenolol (Tenormin)
- Metoprolol (Lopressor, Toprol-XL)
- Propranolol (Inderal)
- Heparin: used for blood clots
- Cyclosporine: used to suppress the immune system
- Trimethoprim-sulfamethoxazole: an antibiotic, also called Bactrim or Septra
The following medications may cause potassium levels to decrease
- Chlorothiazide (Diuril)
- Indapamide (Lozol)
- Metolzaone (Zaroxolyn)
- Furosemide (Lasix)
- Bumetanide (Bumex)
- Torsemide (Demadex)
- Ethacrynic acid (Edecrin)
- Amphotericin B (Fungizone)
- Fluconazole (Diflucan): used to treat fungal infections
- Theophylline (TheoDur): used for asthma
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
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.
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