Potassium is an electrolyte and important in regulating certain body functions such as blood pressure, water content in cells, transmission of nerve impulses, digestion, muscle contraction and heartbeat.  Potassium helps to maintain proper muscle and nerve function and it also play a role in some metabolic processes. 

Potassium is involved in creating the proteins your body needs from amino acids, converting carbohydrates into energy, building muscle, promoting body growth and supporting heart function.  It also helps to maintain the acid-base balance in your body.  Potassium is also important for your body to produce a number of enzymes.

Other benefits of potassium may include preventing kidney problems, lowering your cancer risk, protecting against stroke and lower heart disease risk.

Disease prevention:
The relative deficiency of dietary potassium in the modern diet may play a role in the pathology of some chronic diseases.

Stroke
Several epidemiological studies have suggested that increase potassium intake is associated with decreased risk of stroke.

Osteoporosis
At least four cross-sectional studies have reported significant positive associations between dietary potassium intake and bone mineral density (BMD) in populations of pre-menopausal, peri-menopausal and postmenopausal women as well as elderly men.

Kidney stones
Abnormally high urinary calcium increases the risk of developing kidney stones.  In individuals with a history of developing calcium-containing kidney stones, increase dietary acid load was significantly associated with increased urinary calcium excretion. Increasing dietary potassium intake by increasing fruit and vegetable intake or by taking potassium bicarbonate supplements has been found to decrease urinary calcium excretion.  Additionally, potassium deprivation has been found to increase urinary calcium excretion.

Disease treatment:

High blood pressure (Hypertension)
A number of studies indicate that groups with relative high dietary potassium intakes have lower blood pressures than comparable groups with relatively low potassium intakes.

Deficiency:

An abnormally low plasma potassium concentration is referred to as hypokalemia.  Hypokalemia is most commonly a result of excessive loss of potassium, e.g. from prolonged vomiting, the use of some diuretics, some forms of kidney disease or metabolic disturbances.  The symptoms of hypokalemia are related to alterations in membrane potential and cellular metabolism.  They include fatigue, muscle weakness and cramps and intestinal paralysis, which may lead to bloating, constipation and abdominal pain.  Severe hypokalemia may result in muscular paralysis or abdominal heart rhythms that can be fatal.

Conditions that increase the risk of hypokalemia:

The use of potassium-wasting diuretics
Alcoholism
Severe vomiting and diarrhoea
Overuse of abuse of laxatives
Anorexia nervosa or bulimia
Magnesium depletion
Congestive heart failure

Low dietary intakes of potassium do not generally result in hypokalemia.  However, research indicates that insufficient dietary potassium increases the risk of a number of chronic diseases.

Food sources:

The richest sources of potassium are fruits and vegetables.

 
Adequate intake (AI):

 In 2004, the Food and Nutrition Board of the Institute of Medicine established and adequate intake level (AI) for potassium based on intake levels that have been found to lower blood pressure, reduce salt sensitivity, and minimize the risk of kidney stones. 

Supplements:

Multi-vitamin and mineral supplements do not normally contain more than 99mg of potassium per serving.  Higher doses of supplemental potassium are generally prescribed to prevent and treat potassium depletion and hypokalemia.  The use of more potent potassium supplements in potassium deficiency requires close monitoring of serum potassium concentrations. 

Side effects, precautions, toxicity and drug interactions:

Gastrointestinal symptoms, including nausea, vomiting, abdominal discomfort and diarrhoea are the most common side effects of potassium supplements.  Other potential side effects include muscle weakness, slowed heart rate and abnormal heart rhythm.

Abnormally elevated serum potassium concentrations are referred to as hyperkalemia.  Hyperkalemia occurs when potassium intake exceeds the capacity of the kidneys to eliminate it.  Acute or chronic kidney failure, the use of potassium sparing diuretics and insufficient aldosterone secretion may result in the accumulation of excess potassium due to decreased urinary potassium excretion.