Potassium

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, too. 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 our kidneys are less efficient at eliminating potassium as we 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.

Bone Health

At least one study shows a positive link between a diet rich in potassium and bone health. More research is needed to determine whether a diet high in potassium can reduce bone turnover in people.

Hypokalemia

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. But not all studies agree -- two large studies found no effect on blood pressure. It may be that taking potassium only helps lower blood pressure 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.

Stroke

People who get a lot of potassium in their diet have a lower risk of stroke. However, potassium supplements don't seem to have 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.

Dietary Sources:

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.

Available Forms:

Several potassium supplements are on the market, including potassium acetate, potassium bicarbonate, potassium citrate, potassium chloride, and potassium gluconate. It is 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 tells you to.

The recommended daily intakes of dietary potassium are listed below:

Pediatric

• Infants birth - 6 months: 500 mg or 13 mEq
• Infants 7 months - 12 months: 700 mg or 18 mEq
• Children 1 year: 1,000 mg or 26 mEq
• Children 2 - 5 years: 1,400 mg or 36 mEq
• Children 6 - 9 years: 1,600 mg or 41 mEq
• Children over 10 years: 2,000 mg or 51 mEq

Adult

• 2,000 mg or 51 Meq, including for pregnant and nursing women

Precautions:

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.

Possible Interactions:

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

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 also take NSAIDs, potassium-sparing diuretics, or salt substitutes may be particularly vulnerable to hyperkalemia (too much potassium). 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)
• Heparin (used for blood clots)
• Cyclosporine (used to suppress the immune system)
• Trimethoprimand sulfamethoxazole, called Bactrim or Septra (an antibiotic)
• Beta-blockers: Used to treat high blood pressure, glaucoma, migraines
  • Atenolol (Tenormin)
  • Metoprolol (Lopressor, Toprol-XL)
  • Propranolol (Inderal)

The following medications may cause potassium levels to decrease:

• Thiazide diuretics
  • Hydrochlorothiazide
  • Chlorothiazide (Diuril)
  • Indapamide (Lozol)
  • Metolzaone (Zaroxolyn)
• Loop diuretics
  • Furosemide (Lasix)
  • Bumetanide (Bumex)
  • Torsemide (Demadex)
  • Ethacrynic acid (Edecrin)
• Corticosteroids
• Amphotericin B (Fungizone)
• Antacids
• Insulin
• Fluconazole (Diflucan): Used to treat fungal infections
• Theophylline (TheoDur): Used for asthma
• Laxatives

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.