In a new study published in Circulation, scientists have shown that any salt restriction in the diet improves blood pressure. For the first time, they calculated specific figures for lowering blood pressure with a decrease in the amount of sodium in the diet.
The relationship between dietary salt and blood pressure has long been known. Many studies have shown that people who eat more salt are more likely to suffer from hypertension, while those who consume less salt are less likely. In the new work, scientists decided to get more accurate data.
Excess sodium in the body contributes to water retention in the blood vessels. This increases the load on the heart and blood vessels, and over time can lead to a persistent increase in blood pressure. Hypertension is a risk factor for myocardial infarction and stroke.
The main source of sodium in our diet is table salt (sodium chloride). However, when calculating its content in products, other compounds are also taken into account. We get a significant part of the salt (often more than half) not from our salt shaker, but from finished products.
Russians on average consume 9-12 grams of salt per day, which is an analogue of 3.6-4.8 grams of sodium, which significantly exceeds the recommended level. WHO advises to consume no more than 2 grams of sodium per day, and the American Heart Association — up to 1.5 grams. One teaspoon contains six grams of salt, 2.5 grams of salt contains 1 gram of sodium.
Scientists analyzed 85 studies, the participants of which were followed up to three years. They found that any — even small — reduction in the amount of sodium in the diet led to a decrease in blood pressure. At the same time, this effect turned out to be practically “limitless”: the less salt people consumed, the lower the pressure became.
The study showed that reducing the amount of sodium in the diet for every 2.3 grams per day leads to a decrease in systolic (upper) blood pressure by 5.6 millimeters of mercury, and diastolic diastolic (lower) by 2.3.
«We found that reducing sodium in the diet was also beneficial for people with normal blood pressure who already eat little salt,» said Dr. Marco Vinceti, professor at the Medical School of Reggio Emilia, lead author of the study.
Vincheti believes the new data supports the American Heart Association's recommendations: “Less is more. Even with the use of less than 1.5 grams of salt, there is a decrease in pressure, ”he said.
Scientists point out that in order to reduce the amount of sodium in the diet, the diet needs to be made healthier. One diet designed to lower blood pressure is the Dietary Approaches to Stop Hypertension (DASH) diet. Its main components are: fruits, vegetables, fish, poultry, legumes, nuts. Red meat, sweets and fatty foods are recommended to be limited as much as possible.
“Simply reducing the amount of salt in the diet had an effect in the study, this is not in doubt. But it seems that if you improve your diet in general, then the effect will increase,” said Dr. James Brian Byrd of the University of Michingan School of Medicine.