Blood pressure is necessary for the circulation of blood throughout the body. Blood pressure has two components: the systolic and diastolic blood pressures. The systolic pressure is produced while the heart is contracting and the diastolic pressure is produced while the heart is relaxing. Adequate potassium is needed for muscles to function properly; moderate increases in potassium have beneficial effects in high blood pressure.
Regulation of Potassium
Most of the body's potassium is contained in cells; potassium is constantly leaving the cells. Potassium is not reabsorbed the kidneys, therefore any potassium that leaves the cell leaves the body. The rate of potassium loss from the body is determined by the rate of urine formation in the kidneys; a person who makes more urine loses more potassium. Aldosterone--a hormone that increases sodium absorption and potassium excretion in the kidneys--can also increase the rate of potassium loss.
Potassium Supplementation and Blood Pressure
According to a study published in the April 2005 issue of "Hypertension," the supplementation of potassium citrate and potassium chloride in people with high blood pressure caused a significant decrease in systolic and diastolic blood pressures. The study also indicates that sufficient dietary intake of potassium should lead to similar effects on blood pressure.
Dietary Sources of Potassium
Bananas are a popular source of potassium but are not the best. Other great sources of potassium include sweet potatoes, beet greens, white beans, yogurt, tomato paste, clams, prune juice, carrot juice and soybeans. Potassium intake lowers systolic blood pressure by counteracting the effects of sodium intake in the body; increasing salt intake results in elevations in blood pressure.
Low Systolic Blood Pressure and Low potassium
Health conditions that result in decreased systolic blood pressure also decrease blood flow to the kidneys; this results in increased potassium excretion in the kidneys. Conditions that lower systolic blood pressure include congestive heart failure, liver disease, blood loss, excessive diarrhea and vomiting.
References
- The Harvard Medical School: Potassium lowers blood pressure
- Health.gov: Food Sources of Potassium
- "Harrison's Principles of Internal Medicine"; Dennis L. Kasper M.D., et al.; 2005
- Blood Pressure Association: Why potassium helps to lower blood pressure
