Potassium

In our body about 0.25% is potassium. A 70 kg adult contains a total of about 175 g of potassium.

As an essential mineral potassium is necessary all your cells need potassium for the function of all living cells. It is the major cation (positive ion) inside cells at a concentration of about 150 mmol/L.

Potassium is actively pumped into the cells while sodium is actively pumped out of the cells. This process is mediated by the so-called Na+/K+-ATPase pump.

The resultant concentration differences between the inside and outside of the cell membrane causes what is known as the membrane potential making possible the propagation of impulses in the brain, nerves, and muscles including the heart.

Sources

Eating a variety of foods that contain potassium is the best way to get an adequate amount.

Foods with high sources of potassium include kiwifruit, orange juice, potatoes, bananas, coconut, avocados, apricots, parsnips and turnips.

Many many other fruits, vegetables, legumes, and meats also contain potassium.

Daily intake

Healthy individuals who eat a balanced diet rarely need supplements.

The recommended daily intake is about 4-5 grams in adults.

However, the Western diet in general is rather poor in potassium (about 2 grams per day).

Increasing potassium intake to 4-5 grams per day could ameliorate symptoms associated with potassium deficiency. Here is a list of foods having the highest content of potassium.

Deficiency

A severe shortage of potassium may cause the condition known as hypokalemia (decreased concentration of potassium in the blood). Hypokalemia typically results from loss of potassium through diarrhea, diuresis, or vomiting.

Symptoms are related to alterations in the cells’ membrane potential and metabolism and include muscle weakness and cramps, abnormalities in the electrocardiogram (ECG), intestinal paralysis, decreased reflex response and (in severe cases) abnormal heart rhythm (arrhythmia).

Excess

Hyperkalemia (elevated concentration of patassium in the blood) is the most serious consequence of a too high potassium intake. Hyperkalemia occurs when potassium builds up in the blood faster than the kidneys can remove it. It is most common in individuals with reduced renal function.

Symptoms of hyperkalemia may include tingling of the hands and feet, muscular weakness, and temporary paralysis.

The most serious effect of hyperkalemia is the development of an abnormal heart rhythm (arrhythmia), which can lead to cardiac arrest.

Although hyperkalemia is rare in healthy individuals, oral doses greater than 18 grams taken at one time in individuals not accustomed to high intakes can lead to hyperkalemia.

References: 1 , 2 , 3 , 4