The American Academy of Orthopaedic Surgeons reports that a deficiency in electrolytes like potassium can cause muscle cramps, particularly in your legs. This can occur frequently in the summer, when heat causes you to lose salt and other minerals through your sweat. A healthy, balanced diet should provide sufficient levels of potassium and other minerals for good health, but most multivitamins and sports drinks also contain extra amounts for quick replacement of depleted minerals.
Potassium and Muscle Function
According to the Linus Pauling Institute, potassium plays a very specific role in the electrical function of your cells, which impacts your muscle contractions. Potassium is an electrolyte, meaning it breaks down into ions, electrically charged particles, your body uses to conduct electricity. Potassium is the most abundant ion inside of your cells, and it works with sodium outside of your cells to create an electrical and chemical system across cell membranes. This system is called the membrane potential, and it is important in muscle contractions.
Potassium and Leg Cramps
When the potassium in your cells is inadequate, it can disrupt the membrane potential, which can cause cramping in your leg muscles. A severe deficiency in potassium is called hypokalemia. Symptoms of hypokalemia include muscle cramps and weakness, fatigue and abnormal heart rate. You can have a deficiency in potassium simply from not eating enough potassium in your diet; however, alcoholism, abuse of laxatives, eating disorders, and a magnesium deficiency can also contribute to your body's loss of potassium.
If you are suffering from frequent leg cramps, a mild potassium deficiency or even hypokalemia could be the cause. Make sure you are getting at least 4,700 milligrams or 4.7 grams of potassium daily. If you are not getting this through your diet, you should be taking a multivitamin or a specific potassium supplement to augment your potassium intake and prevent muscle cramps. If you exercise and sweat frequently, you could be losing potassium at a higher rate and may want to take a potassium supplement to prevent leg cramps.
Natural Sources and Supplements
You can find potassium naturally in fruits and vegetables. However, the most abundant sources of potassium are bananas, potatoes with skin, plums, raisins, and prunes. Most multivitamins contain potassium, but it is often a minor amount -- frequently little more than 2 percent of your daily needs. If you suspect your leg cramps are caused by a potassium deficiency, you can get a prescription from your physician for a higher dose of potassium supplements.