Potassium is a mineral that helps the kidneys function normally. It also plays a key role in cardiac, skeletal, and smooth muscle contraction, making it an important nutrient for normal heart, digestive, and muscular function. A diet high in potassium from fruits, vegetables, and legumes is generally recommended for optimum heart health.

Having too much potassium in the blood is called hyperkalemia and having too little in the blood is known as hypokalemia. Proper balance of potassium in the body depends on sodium. Therefore, excessive use of sodium may deplete the body’s stores of potassium. Other conditions that can cause potassium deficiency include diarrhea, vomiting, excessive sweating, malnutrition, and use of diuretics. In addition, coffee and alcohol can increase the amount of potassium excreted in the urine. Adequate amounts of magnesium are also needed to maintain normal levels of potassium.

For most people, a healthy diet rich in vegetables and fruits provides all of the potassium needed. The elderly are at high risk for developing hyperkalemia due to decreased kidney function that often occurs as one ages. Older people should be careful when taking medication that may further affect potassium levels in the body, such as nonsteroidal anti-inflammatories (NSAIDs) and ACE inhibitors.

The most important use of potassium is to treat the symptoms of hypokalemia, which include weakness, lack of energy, muscle cramps, stomach disturbances, an irregular heartbeat, and an abnormal EKG (electrocardiogram, a test that measures heart function). Treatment of this condition takes place under the guidance and direction of a physician.

High dietary intake of potassium from fruits and vegetables throughout one’s life helps to preserve bone mass thereby preventing bone loss that can lead to osteoporosis.

High Blood Pressure
Some studies have linked low dietary potassium intake with high blood pressure. The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends adequate amounts of potassium in the diet, along with other measures such as dietary calcium and weight loss, to prevent the development of high blood pressure. Similarly, the Dietary Approaches to Stop Hypertension (DASH) diet emphasizes eating foods rich in fruits, vegetables, and low- or non-fat dairy products to provide high intake of potassium, as well as magnesium and calcium.

In several population based studies evaluating very large groups of men and women over time, a diet rich in potassium was associated with a reduced risk of stroke. For the men, this seems to be particularly true among those with high blood pressure and/or those taking diuretics (blood pressure medications that help the kidneys eliminate sodium and water from the body). Potassium supplements, however, do not seem reduce the risk of stroke.

Inflammatory Bowel Disease (IBD)
Amongst other nutrient deficiencies, people with IBD (namely, ulcerative colitis or Crohn’s disease) often have low levels of potassium.

Several studies have suggested that diets low in potassium are associated with poor lung function and even asthma in children compared to those who eat normal amounts of potassium. Enhancing dietary intake of potassium through foods such as fish, fruits, and vegetables may, therefore, prove to be of value for preventing or treating asthma.