High potassium foods have been well documented to protect against hypertension, osteoporosis, and kidney stones. It has also been associated with less cardiovascular disease and other heart problems. It is well known to doctors that a poor potassium level can cause arrhythmias (irregular heart beats) in the heart. However, it is not as well known that it can also reduce the heart's mechanical function – its ability to pump blood. And it is not well known that the poor potassium level results in increased free radical formation.
How Does A Poor Potassium Sodium Ratio Cause Heart Problems?
Dr. Young in an editorial (1) from 2006 discusses the implications of the article we discussed in the last post. It has been shown in animals and in humans that too high a level of sodium or too low a level of potassium causes the ventricle to function poorly. This is because the ventricle does not relax as fully, or as fast, as when potassium and sodium are at a proper level. The result is less filling of the ventricle, and less blood that can be pumped through the blood vessels.
In the article discussed in the last post, this decreased function of the ventricle from inadequate potassium was associated with increased free radical (ROS) formation. In 1992 Dr. Young had shown that improved potassium levels reduced free radical levels in the cell.
Free Radical Formation May Be The Cause
In this editorial he ties together the evidence about increased free radical formation being the possible cause of this reduced heart function. He cites several other studies consistent with this theory. One showed that vitamin C (an antioxidant) improved heart diastolic function. Two other studies connected how the free radicals could interfere with calcium movement in cells, thus interfering with the ventricle's ability to relax and fill with blood.
The worsening of diastolic function is one of the earliest abnormalities in heart function from inadequate potassium. It occurs before there is any abnormality in the systolic (when the heart contracts) function. This improvement in the diastolic function (when the heart relaxes) from potassium occurs even before blood pressure is lowered.
Thus more and more blanks are being filled in on how an improved potassium sodium ratio improves heart function. The question is not whether a high ratio improves heart function. That has been well established. But it is how. It is the mechanisms the cell uses to bring about these improvements. Each study confirms the basic finding that a high potassium to sodium ratio in the diet helps the heart.
Although Dr. Young wrote the editorial in consideration of the use of potassium supplements to improve the potassium level in the blood, the potassium level in the body is best improved with high potassium foods.
Tables Of High Potassium Foods
To find tables of high potassium foods, please look under the “Links to Food Potassium Tables” tab at the top of the page.
1. Potassium depletion and diastolic dysfunction. Young DB. Hypertension. 2006 Aug;48(2):201-2. Epub 2006 Jul 3.