Potassium - Does It Protect Us From High Blood Pressure?

It is no secret that nutrition in industrialized countries has undergone significant changes in the last century - a century and a half. It is not possible to judge whether this brings negatives or positives, because it is a fact that today food deficiencies or the risk of microbial contamination when eating food are significantly rarer. Of course, there are other features.

A significant portion of the foods on the table today are the product of a transformation in which, among other things, there is an increase in sodium levels and a decrease in potassium levels. There are studies that find a link between the altered ratio of sodium and potassium intake and the growing number of patients with hypertension.

The reason: what role do sodium and potassium play on blood pressure?

We've heard that a lot of salt "retains more water and raises blood pressure." Increased sodium intake is indeed associated with hypertension and its worsening. But in addition to the purely volumetric load, there are other consequences.

There are many mechanisms by which sodium and potassium affect blood pressure values. The human kidney is prone to sodium retention and potassium excretion - a property that played a protective role on homeostasis (balance) in sodium and body fluid volume, and which was especially useful for prehistoric people whose diet was consisted of foods low in sodium and rich in potassium.

Today's eating habits, on the other hand, are associated with foods rich in sodium and poorer in potassium. In the context of renal physiology, this means that there is a potential risk of sodium overload and potassium deficiency in the body. In cases of essential arterial hypertension, the relatively increased amount of the hormone aldosterone stimulates the cellular sodium transport systems at various levels in the renal nephrons, resulting in additional sodium retention. One of the important mechanisms for the reabsorption of sodium from the formed urine is at the expense of its exchange with potassium. Therefore, not only does sodium retention increase, but this is also associated with additional potassium losses.

At the level of blood vessels, a diet rich in sodium can cause hypertension in the way of the direct effect that sodium has on the smooth muscle fibers that make up the vessel wall, especially the arteries. It leads to vasoconstriction - vasodilation, which increases peripheral resistance.

In response to the increased amount of sodium in the blood, the adrenal glands produce a specific factor that increases the intracellular amount of calcium in smooth muscle cells, which also stimulates their constriction.

Additionally, sodium retention provokes decreased secretion of nitric oxide (NO), which has a vasodilating (dilating) effect.

Peripheral vasoconstriction, which sodium retention stimulates by the described mechanisms, contributes to the genesis of arterial hypertension.

In cases where the person already suffers from essential hypertension, the loss of potassium in turn further stimulates sodium retention, as it causes intracellular acidosis, which stimulates another transport mechanism in the kidney, exchanging sodium with hydrogen ions. Thus, in the body's attempt to maintain the acid balance, a vicious circle is formed.

What happens in the opposite case?

A diet rich in potassium in patients with hypertension stimulates natriuresis (increased urinary sodium excretion), which results in lower blood pressure. This observation is mainly explained by the inactivation of the sodium-chlorine transporter (an aldosterone-independent mechanism), reduction of intracellular calcium and vasodilation.

Observations and research show that sodium and potassium play opposite roles in both blood pressure control and cardiovascular prophylaxis.

What are the recommendations?

Of course, a reasonable restriction of salt and intake of more foods rich in potassium. However, the decision to supplement with potassium should be discussed with your doctor. Some patients with hypertension also suffer from impaired renal function, which is prone to hyperkalemia. High potassium levels carry the risk of conduction disturbances.

Each patient affected by hypertension should make a serious revision of the amount of sodium in their diet, as well as check whether they consume enough potassium. A pure dietary solution can contribute favorably to drug therapy and reduce the risk of complications.