The role of sodium and potassium in blood pressure control

 High blood pressure (hypertension) is a condition that is affecting an increasing number of people and is a significant risk factor for the development of heart disease and for heart attack. It is not surprising, therefore, that prevention measures, which would minimize the incidence of hypertension, are given so much importance. As one of the prevention measures, suppression of salty foods is often recommended. But can hypertension be associated with high sodium intake and low potassium intake, and can reduced salt intake (sodium chloride) affect blood pressure regulation?

The importance of salt

Many of the foods we consume are a natural source of salt, but salt is added to the food for the purpose of preserving or improving the taste.

Sodium and chlorine play an important role in regulating blood pressure, controlling the balance of body fluids, and providing conditions for the normal functioning of muscles and nerves. Sodium also allows the absorption of glucose and amino acids.

An adult’s body contains approximately 90 grams of sodium, half is in the blood and other body fluids, just over a third is contained in the bones, and the rest is found within the body’s cells.

The average daily intake of salt varies between 2 and 6 grams, although 0.5 g would be enough to maintain health. The needs are greater with larger losses, for example during menstruation, lactation or increased sweating. Approximately 1 gram of sodium is equivalent to 2.5 grams of salt.

Potassium

The so-called a primitive diet characterized by a high intake of fresh, unprocessed or minimally processed foods provides significantly higher amounts of potassium than the diet of modern man which in turn is characterized by a high intake of processed foods. However, except in cases of prolonged vomiting, diarrhea, or the use of diuretics that stimulate potassium excretion, potassium deficiency is rare.

The best way to get adequate amounts of potassium is to consume fruits and vegetables. Approximately 2.5 to 5.8 g of potassium is ingested daily. In the body, potassium is mainly found within cells and is needed to regulate water balance, acid-base balance, blood pressure and neuromuscular functions. This mineral also plays an important role in transmitting electrical impulses to the heart.

Blood pressure - the opposite action of two vital elements, sodium and potassium

The ability of the kidneys to excrete or retain sodium is a key factor in regulating blood pressure. Most studies have shown that reduced salt intake results in a reduction in blood pressure, and the effect is most pronounced in people with high blood pressure, followed by obese and elderly people. The body's response to reduced salt intake varies from individual to individual and it is possible that, in people whose blood pressure levels are within normal limits, they will not result in visible (measurable) changes.

On the other hand, decreased blood pressure may be associated with elevated potassium levels which may in turn be the result of increased food intake or the ability of potassium to enhance sodium excretion and its vasoactive effect on blood vessels.

It is believed that the balance between potassium and sodium in the body plays one of the key roles in regulating blood pressure.

Foods rich in potassium, poor in sodium

The best source of potassium is fresh food, minimally processed. On the other hand, fresh food contains smaller amounts of sodium, while processed is the main dietary source of sodium.

Table 1: Potassium-rich and sodium-poor foods (unprocessed)

Lifestyle has the biggest impact on blood pressure

Obesity, lack of physical activity and low potassium intake have a stronger effect on blood pressure than high salt intake. Low calcium and magnesium intake and a high proportion of saturated fatty acids relative to omega-3 polyunsaturated fatty acids have also been shown to be significant risk factors.

Recently, the DASH diet (Dietary Approaches to Stop Hypertension), which is characterized by a high proportion of fruits, vegetables and whole grains (to increase the intake of potassium and dietary fiber), and the intake of dairy products with low in milk fat, fish, white poultry and lean meat. When salt intake is kept under control and when it is constant, with the DASH diet, blood pressure drops significantly.

Table 2: Lifestyle changes that may affect blood pressure reduction

The body can get used to reduced sodium intake through salt; it is believed that the adjustment to reduce salt intake by half of the usual, takes 2-3 months. Today, the taste of food is improved by alternative flavor enhancers - pepper, fresh and dried herbs. A salt substitute, which is based on potassium as one of the ingredients, can also be an alternative, and along the way contributes to increased potassium intake.