The Teamwork of Sodium and Potassium in Our Cells
Sodium and potassium persistently work together at the cellular level to control cellular volume, pH and membrane potential. In a potassium deficit scenario, sodium enters the cell to maintain cellular volume. Then water follows sodium into the cells, increasing pressure on artery walls. Over time this extra pressure can lead to stiffness, vasoconstriction of the arteries and eventually high blood pressure. On the other hand, ample dietary potassium causes sodium pump stimulation in the cells, which ultimately relaxes blood vessels and allows blood to flow freely, keeping blood pressure at normal levels.
Let's Look at Some History
Our problem with potassium may date back to the Stone Age. Hunter gatherers ate a plant-based diet high in potassium and low in sodium, hence, the human kidney evolved to keep the body's electrolyte balance by readily excreting potassium and conserving sodium. The modern Western diet today has essentially the opposite proportions of the early human diet because whole foods make up a smaller part of the western diet than processed foods.
High Sodium, Low Potassium and the Average American Diet
For years, sodium has served as the dietary burden for heart disease. There is no doubt about it, Americans consume too much salt as a result of a diet which has become heavy in processed, high sodium foods and light in fruits and vegetables. This may be the reason Americans come up short on potassium in the diet and research supports reason for concern.
Research shows that Americans live day to day with a more moderate potassium deficit, which poses longer term health threats. A moderate potassium deficiency can lead to hypertension and related cardiovascular events, as well as an increased risk for bone loss and kidney stones. A severe potassium deficiency-rare in healthy individuals, can result in serious health consequences such as cardia arrhythmias, muscle weakness, and glucose intolerance. Observational studies found that the dietary sodium to potassium ratio had a stronger association with blood pressure than sodium or potassium alone. In countries such as Japan where sodium intake is high yet people consume traditional diets of largely whole foods, rates of high blood pressure remain lower than those of Western nations.
Some Helpful Hints
For some people, increasing potassium may be a more useful heart health strategy than simply trying to reduce sodium. After all, it is generally easier to get Americans to eat more, not less.
Foods rich in potassium include; potatoes, acorn squash, chickpeas, lentils, and legumes. Numerous fish, including tuna, halibut, salmon, and flounder are potassium rich. Beef, chicken, and pork also contain ample amounts of potassium; just make sure they are lean sources.
People who want to try potassium supplements need to proceed with caution and seek a physician's advice before taking any supplement.
Created by Shannon Weston, BS, Dietetic Intern
Resources
1. Today's Dietitian (Volume 10 Number 2). "The Pressure's On: Increasing Potassium for Heart Health."