Sodium is an essential nutrient; we need it in our diets. Sodium is found in all extracellular fluids in our body and involved in a wide range of physiological reactions. Health regulatory officials have been recommending for some time that people reduce their salt (sodium chloride) intake to combat hypertension or high blood pressure and, consequently, reducing mortality from coronary heart disease and stroke. Sodium has also been implicated in increases in blood pressure with age. US officials have recommended a safe minimum level of 500 milligrams (mg) sodium per day and an upper level of 2,400 mg sodium per day.

Potassium is found in many parts of the body; it is involved in fluid and electrolyte balance. It has an important role in heart muscle activity and is found in many metabolic pathways. Epidemiological and animal studies indicate that the risk of stroke-related deaths is inversely related to potassium intake over the entire range of blood pressures and the relationship appears to be dose dependent.

That means the higher the potassium intake, the lower the risk. US officials believe that a diet containing approximately 3.5g of potassium / day may contribute to reduced risk of stroke, which is especially common among blacks and older people of all races.

The combination of a low-sodium, high potassium intake has been found to be associated with the lowest blood pressure levels and the lowest frequency of stroke in individuals and populations. High potassium and low sodium - that`s where the banana come in.

United States Food and Drug Administration has allowed the following health claim to be made for bananas: diets containing foods that are good sources of potassium and low in sodium may reduce the risk of high blood pressure and stroke. Bananas qualify for the health claim because they contain at least 350 mg of potassium and 140 mg or less of sodium (per normal serving). Bananas also are low in fat, low in saturated fat, and low in cholesterol.