Proper Understanding About Salt Intake

For decades, salt has been blamed for a global rise in hypertension and cardiovascular diseases. It is often demonised as a white poison. There have been health campaigns focusing on cutting down salt intake as a preventive measure against hypertension. Although excessive salt intake has been linked to high blood pressure, the relationship is complex. Now, research has come up with the suggestion of judiciously taking it for its regulating role in maintaining blood pressure. Hence, it is necessary to focus on those perspectives and individualised dietary salt consumption. 

Our body cannot produce salt or sodium chloride on its own, but it is an essential mineral for regulating blood pressure. It not only regulates fluid balance but is also necessary for nerve conduction and muscle function. The sodium that is contributed from salt helps maintain the osmotic equilibrium necessary to keep fluids distributed inside and outside cells. A low level of sodium causes hyponatremia and fatigue, confusion, and life-threatening complications may result. 

Blood pressure 

Blood pressure is closely linked to the body’s sodium concentration and fluid balance. If sodium level increases, the body retains more water, leading to an increase in blood volume and, in turn, blood pressure. This is the basis of the recommendation for a lower intake of salt.  Public health campaigns have focused on the issue of low salt intake among the general population. The popular slogan “less salt, lower blood pressure” has been promoted so widely that it has become a household norm. However, recent studies have challenged it. Both excessive and insufficient salt consumption can be harmful to our bodies. 

The consumption of salt as low as 3 grams of sodium per day has been shown to cause increase incidence of heart attacks and mortality. Our body needs a certain amount of sodium to maintain vascular equilibrium and for the normal functioning of the kidneys. When the sodium level falls too low, our hormonal system tries to retain it and raises blood pressure. Thus, excessively low intake might cause high blood pressure. 

Our traditional diet often included salt as a natural preservative and flavour enhancer. The rock salt, sea salt, contains magnesium, potassium, and calcium besides sodium. All these minerals are essential for vascular health. All traditional medical systems recommend moderate salt intake and promote it as a vital substance necessary for improved digestion, circulation, and energy balance. 

Refined table salt is typically devoid of other natural minerals and often contains anti-caking agents. Those minerals counteract the hypertensive effects of sodium by relaxing blood vessels. There are individual differences in the effects of salt intake. Only a few percent of people are salt sensitive and show an increase in blood pressure with increased salt intake. Genetics, kidney function, age, physical activity, and dietary patterns affect salt sensitivity. For many, moderate intake of salt has no or minimal effect on blood pressure. 

The environmental factor also plays a role in salt intake. In tropical countries like ours, people lose a considerable amount of sodium through sweat. Therefore, salt restriction in such a climate can cause hyponatremia, characterised by dehydration, fatigue, and muscle cramps. Both physical workers and athletes need adequate compensation of salt to replenish electrolytes lost owing to exertion. Hence, dietary recommendations should be context-specific and vary from place to place. 

In this context, the role of potassium cannot be overlooked. Potassium causes vasodilation and helps the kidneys excrete excess sodium, counteracting sodium’s effect. Fruits, vegetables, legumes, and whole grains that are rich in potassium can contribute to maintaining normal blood pressure without excessive reduction in salt intake. 

Moreover, the sodium-to-potassium ratio is a better predictor of hypertension than sodium alone. A balanced diet that contains sufficient potassium along with moderate sodium is better for a healthy blood pressure level than a low salt intake alone. Hence, it is recommended to increase potassium intake for better blood pressure control than cutting salt intake only. 

Globally more than a billion people are affected by hypertension and the World Health organisation (WHO) recommends intake to less than 5 grams of salt (equivalent to less than 2 grams of sodium). However, this blanket recommendation has been criticised in recent times. It is a known fact that processed foods often contain excess sodium, the traditional diets in developing countries derive sodium mainly from added salt during cooking. 

Thus, it is better to take natural salt in moderation and avoid processed foods than to eat less salt. The processed foods not only contain excess salt but also unhealthy fats, sugars, and preservatives that in combination contribute to cardiovascular problems.  

Balance

Our ultimate goal should be focused on using salt in moderation. It is, therefore, recommended to use natural salts such as sea salt or rock salt than table salt. The highly processed foods should be avoided and people should remain hydrated in hot climates and during physical activity. It is also advised to use potassium-rich foods such as bananas, lentils, and citrus fruits. 

The debate about the amount of salt intake remains forever. It is a known fact that excessive salt intake contributes to hypertension; excessive restriction also poses health risks. Therefore, it is recommended to use it in balance, context, and quality. As sodium is a biological necessity, it should not be taken lightly, as it is essential for regulating blood pressure. Hence, salt is not the sole cause of the global hypertension crisis, but an imbalance in our overall diet is. 

(Dr. Lohani is the clinical director at the Nepal Poison Information Centre. lohanis@gmail.com)