There are many health damaging effects of a poor potassium sodium ratio that occur even before blood pressure begins to rise. Last post we discussed how a poor potassium sodium ratio causes poor diastolic function of the heart even before blood pressure rises. If it goes on long enough, the poor ratio can lead to scarring in the heart.
In the short term this poor diastolic function can be easily corrected by simply getting a favorable potassium sodium ratio. If not corrected, over time this dysfunction becomes more difficult to reverse. Areas of fibrosis (scarring) begin to show up in the heart when examined under the microscope. A series of studies was done to examine the subcellular mechanism that leads to the scarring in the heart seen in heart failure.
Subcellular Look At Heart Failure
These studies were recently reviewed in an article (1) by the researchers who did this series of experiments. In animals experimentally subjected to high salt intake (potassium sodium ratio of 0.53) and high amounts of aldosterone, small foci of necrosis (dead heart cells) begin to form in the heart ventricle within 4 weeks. These areas of dead heart cells form small areas of scar tissue in the heart, much smaller than occurs from a heart attack.
Over time these take up an increasing percentage of the heart. When the percentage is too much, the remaining heart muscle cells cannot pump blood strongly enough. This is known as heart failure.
How A Poor Potassium Sodium Ratio Damages Heart Cells
The researchers studied the mechanism for this at the subcellular level. To summarize their findings, an increased salt intake leads to a shift in the calcium load inside the heart cell. Calcium builds up in the mitochondria causing the mitochondria to function poorly. Because the mitochondria are the power plants of the cell, all the functions performed by the cell cannot keep up and the cell dies.
The researchers found that this calcium buildup also was associated with an increase in free radicals (ROS). Free radicals interfere with the movement of electrons needed by the mitochondria for their work.
A Poor Ratio Messes Up Pores
Ultimately two pores in the mitochondrial membrane begin to function poorly, the mPTP pore and the BK(Ca) pore. The mPTP pore lets in too much fluid. The mitochondria swell and can no longer function.
The BK(Ca) pore is believed to affect the mPTP pore. When it can let potassium into the mitochondria, it can keep the mPTP pore from opening too much. But the BK(Ca) pore opens and closes based on the calcium concentration. Because there is too much calcium in the mitochondria, the BK(Ca) pore cannot hold back the mPTP pore. The mitochondria swell, and then the cell swells and bursts.
Cell Burst Means Scar
When a cell swells and bursts, the cell contents that are released attract inflammatory cells. These inflammatory cells set off a chain reaction that results in scar tissue. These small areas of scarring (fibrosis) eventually get larger and larger, leading to heart failure.
Hypertension can lead to irreversible damage. This discussion demonstrates one example of how this can happen. Similar types of subcellular damage occur to other cells in the body also. This particular example is one of the best detailed series of experiments at showing how this can happen.
It's Not Just The Pressure
With these studies we begin to get an excellent understanding of how the potassium sodium balance affects the workings inside the cell. The effects of a poor potassium sodium ratio are not limited to simply increasing blood pressure. The effects occur throughout the body, affecting every cell.
As demonstrated in the ventricle of the heart, it is not just the mechanical effects of the pressure in the arteries that is important. The mechanical elevation of blood pressure is just an end result of many disrupted cellular functions. Unless corrected in a timely manner, the cellular damage leads to irreversible changes.
In some earlier experiments the researchers had one set of control animals get a potassium sodium ratio of 1.33. These animals did not develop the scarring in the heart.
How You Can Prevent Heart Failure
If you, like most Americans, have been on a high sodium, low potassium diet for a long time, you can stop these changes and possibly reverse some of them. If you are young, you can prevent them with a high potassium, low sodium diet.
Tables Of High Potassium Foods
To find tables with the potassium and sodium content of foods, use the List of Posts tab and look for post with the food group your food of interest is in.
1. Intracellular calcium overloading and oxidative stress in cardiomyocyte necrosis via a mitochondriocentric signal-transducer-effector pathway. Mazen Shaheen, MD, Yaser Cheema, MD, Atta U Shahbaz, MD, Syamal K Bhattacharya, PhD, and Karl T Weber, MD. Exp Clin Cardiol. 2011 Winter; 16(4): 109–115.