Too little salt increases death rate in heart disease

Even too little salt is unhealthy: in one study, the death rate increased due to a lower salt intake

04/05/2011

Insufficient salt intake can cause lasting damage to the cardiovascular system. This was discovered by researchers in the course of a study by the University of Leuven. Too little salt can be even more harmful to the organism than too much. So far, the simple formula was: Better not eat salt to endanger the blood pressure or circulation. The study results now provide a completely new picture on the subject.

Insufficient salt increases death rate in cardiovascular diseases
Who eats too much salt, lives unhealthy. This health advice of many doctors is now considered standard. But even a small salt intake that is detectable in urine, indicates a connection of a higher mortality rate in cardiovascular problems. Belgian researchers at the University of Leuven have come to the surprising conclusion that too little salt can be even more harmful to the heart and circulation than too much. During a long-term study with around 3,500 subjects, the researchers analyzed the average salt intake of the participants from the urine. In the course of the study, it became clear that below average salt excretion is associated with an increased risk of cardiovascular death. On the other hand, if a higher than average saline excretion was measured, a direct context could not be deduced.

Like the doctors in the science magazine „Jama“ The standard recommendation of cardiologists to save salt is not substantiated by the study results in relation to the risk of death. The argument that salt intake should be limited due to the risk of high blood pressure, for example to prevent heart attacks, is not refuted. Rather, the risk of death due to cardiovascular disease was investigated during the study. A lower, below-average salt intake could not reduce the risk of heart disease, as the researchers write. The opposite was more the case.

Lower blood pressure by saving salt
The authors of the study do not want to misunderstand their results. It is still scientifically proven that a lower intake of salt causes hypotensive effects in hypertensive patients. Therefore, patients who have been prescribed salt saving should continue to follow the doctor's instructions, as study director Katarzyna Stolarz-Skrzypek stresses in the report. Nevertheless, the observations made must be included in further research, because the physicians observed a declining death rate in heart patients, who had a higher salt content in the urine.

Death rate lower with high salt consumption
The 8-year study included 3681 people who did not have known heart disease at the beginning of the long-term study. In the course of the study work, the urine values ​​and in some cases the blood pressure values ​​were continuously measured. At the conclusion of the study, all deaths related to cardiovascular disease were investigated. A total of 50 subjects with low salt levels in the urine died of heart disease. Twenty-four participants showed mean values, died and people with high to very high salt secretions died in exactly ten cases.

In some subjects, the development of blood pressure levels was also observed. Apparently, the researchers said, the lower salt intake had only a slight effect on hypertension. Only the systolic value (the higher blood pressure that results when the heart contracts and the blood gets into the vessels) increased with a higher consumption of salt. „The relationship between systolic blood pressure and saline excretion can not be translated to lower mortality or improved survival“, the study authors argue. „On the contrary, a low salt excretion predicted a higher mortality from cardiovascular disease.“ In previous intervention studies, researchers looked at how blood pressure changes when people eat only 5 grams of salt a day instead of 10. These studies also showed only minor changes in blood pressure.

How much salt is healthy now?
Salt is as vital as the daily hydration. The sodium in the salt regulates the water balance of humans. Widely recommended for adults is a daily salt intake of 5 grams. Whether daily, additional salt is still necessary today, depends entirely on the eating habits of the individual. Salt is already hidden in many ready-to-eat foods. So if you eat a lot of ready-made pizza and hamburger, you should do without additional salting. In half a pizza from the supermarket alone, an average of 3.3 grams of salt is contained. But even 100 grams of sausage or cheese can already have up to six grams of salt. As a rule, multiply the sodium content stated on the packaging by 2.5 to calculate the amount of salt in the product. Who drives a lot of sports, especially in the summer and tends to excessive sweating, should pay attention to an additional salt intake under certain circumstances. Because too little salt can have life-threatening consequences because it thirst is lost and threatens an inner dehydration. Those suffering from cardiovascular disease should discuss daily salt intake with their doctor. (Sb)

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Image: Sybille Daden