Your body uses the potassium that you get from foods in many processes, including blood pressure regulation. Potassium counteracts the effects of sodium, which raises blood pressure by causing fluids to move from cells into the bloodstream. Over time, too little potassium to check this action can result in chronic high blood pressure, or hypertension, and damage to blood vessels. If you don't get enough potassium from your diet, you may also be more likely to experience hypokalemia, or insufficient blood potassium levels, induced by dehydration and some medications.
Sodium-Potassium Balance
When the amount of potassium in your blood is higher than that of sodium, the fluids in your blood and cells remain stable and your metabolism functions normally. A shift in this ratio, however, causes the body to try to dilute the sodium concentration, sending fluid into the blood and increasing blood volume and the pressure needed to transport the blood. The U.S. Department of Agriculture relates that, in general, while blood pressure is directly related to sodium intake, potassium buffers this reaction. You should consume at least 4,700 mg of potassium and no more than 2,300 mg of sodium per day to achieve this balance. If you already have a heart condition, 1,500 mg of sodium is your suggested upper intake.
Sodium-Potassium Imbalance
Most Americans don't hit those daily mineral intake marks, averaging about half of the recommended potassium and about 50 percent more than the recommended sodium values. If your potassium intake is low, sodium levels in body fluids can easily surpass potassium in an unhealthy ratio. The Trials of Hypertension Prevention study published in the "Archives of Internal Medicine" in 2009 revealed a higher incidence of heart disease in people with prehypertension whose urinary sodium measured higher than urinary potassium. This indicates that an improved potassium-to-sodium ratio can decrease the risk of high blood pressure, a major contributing factor to heart disease.
Effects of Diuretics
Dietary intake isn't the only possible cause of a potassium deficiency. If you have high blood pressure already and take diuretics, these drugs can cause you to shed potassium along with sodium through urine. With your existing cardiovascular risk, some diuretics may do more harm than good. Your doctor can prescribe a potassium-saving diuretic, if necessary.
Solution
Potassium deficiency that increases the detrimental effects of sodium surplus can and should be prevented or addressed through diet. The Trials of Hypertension Prevention study found that a higher potassium-to-sodium ratio in the diet decreases cardiovascular risk. Therefore, according to the Harvard School of Public Health, increasing potassium while reducing sodium intakes is a viable means of improving high blood pressure. You can use the information on food labels to choose meats, fish, dairy products, grains, fruits and vegetables with mineral contents that help you achieve the recommended daily values. Use diuretics and potassium supplements under doctor supervision only.
References
- USDA; Dietary Guidelines for Americans; December 2010
- Harvard School of Public Health: Lower Salt and Sodium
- National Institutes of Health; Sodium-Potassium Ratio Linked to Cardiovascular Disease Risk; January 2009
- MedlinePlus: Potassium in Diet
- Harvard School of Public Health: Salt and Heart Disease
