Will Cornell Medical College in the United States has used mouse experiments to prove that high salt diet can affect brain health, leading to changes in the intestinal immune system, and then lead to cognitive deficits. The popular point is that eating too much salt can make people stupid. What about eating too little salt? Some scientists believe that low salt diet and high salt diet are equally dangerous.
Sodium is a key element in salt, which is essential for the body to maintain fluid balance, transport oxygen and nutrients, and nerve signal transduction. In fact, most people eat more salt than the scientifically recommended standard and experts are trying to convince us to reduce salt intake.
Photo 2: blue cheese contains 2.7 grams of salt per 100 grams, higher than salt content in seawater.
Generally speaking, adults do not consume more than 6 grams of salt per day. The average consumption of the British people is close to 8 grams, while that of the United States is 8.5 grams, while that of China is close to 9.1 grams. But only a quarter of the salt we consume every day comes from our own additions, and the rest is hidden in the foods we buy, including bread, sauce, soup and various cereals.
On food labels, manufacturers usually label only sodium, not salt, which leads us to think that we eat very little salt.
Salt is composed of sodium and chloride ions. About 2.5 grams of salt, about 1 grams of sodium. Nutritionist May Simpkin said: A lot of people dont know this, just think sodium and salt are the same thing.
Many studies have found that excessive salt intake can lead to high blood pressure, which in turn can lead to stroke and heart disease. When we eat salt, the body retains more water, causing blood pressure to rise until our kidneys expel it.
According to the World Health Organization (WHO), prolonged intake of excessive salt can cause arterial stress and prolong the duration of hypertension, which is responsible for 62% of stroke and 49% of coronary heart disease.
The study found that five grams of salt a day increased the risk of cardiovascular disease by 17% and stroke by 23%.
Photo 3: barrel popcorn (about 250 grams) may contain 5 grams of salt, almost equal to the average persons intake of 1 days.
What will happen if we reduce the intake of salt? Researchers found that a 1.4 gram reduction in daily salt intake may help lower blood pressure, which in turn reduces the risk of stroke by 42%. But researchers find it difficult to distinguish low salt from other dietary and lifestyle effects. People who pay more attention to salt intake are likely to eat healthier, exercise more, smoke less and drink less.
Photo 4: a cup of miso soup contains 2.7 grams of salt.
Francesco Cappuccio, professor of cardiovascular medicine and epidemiology at the University of Warwick Medical School, said: It is almost impossible to complete a randomized trial of the effects of salt on the human body.
At the end of the 60s, the Japanese government launched a campaign to persuade people to reduce salt intake. Since then, Japanese salt intake has dropped from 13.5 grams a day to 12 grams a day. During the same period, peoples blood pressure dropped, and stroke mortality dropped by 80%.
In Finland, daily salt intake dropped from 12 grams in the late 1970s to 9 grams in 2002, and death rates from stroke and heart disease fell by 75-80% over the same period.
However, the effects of salt intake on blood pressure and heart health vary from person to person. Our sensitivity to salt varies from person to person, depending on factors such as race, age, body mass index, health status and family history of hypertension.
Fig. 5: Two pieces of sushi contain 0.5 grams of salt, but a tablespoon of soy sauce adds 2.2 grams of salt, that is, the total salt content is 2.7 grams.
Some studies have found that people who are more sensitive to salt are more likely to suffer from salt related hypertension. But many scientists believe that low salt diet and high salt intake are all risk factors for hypertension. Daily intake of less than 5.6 grams or more than 12.5 grams of salt will have a negative impact on health.
Studies have shown that low salt intake (less than 7.5 grams) is associated with an increased risk of cardiovascular disease and death compared with the moderate intake of 12.5 grams of salt per day.
Andrew Mente, a nutritional epidemiologist at McMaster University in Canada, believes that reducing salt intake reduces the risk of hypertension, but there are no other benefits. Increasing salt intake from low to moderate levels may also help.
Photo 7: although it tastes sweeter, even a single Cupcake contains about 1 grams of salt.
But not everyone agrees. Professor Cappuccio has made it clear that reducing salt intake can lower blood pressure for everyone, not just for those who eat too much salt.
Sara Stanner, science director of the British Nutrition Foundation, agrees that there is ample evidence that reducing salt intake in hypertensive patients reduces blood pressure and heart disease risk. Moreover, not many people consume less than 3 grams of salt, which is considered dangerously low in some studies.
Because the food we buy contains so much salt, its impossible for us to eat less than three grams of salt a day, Steiner said.
Photo 8: frozen Italy Sausage Pizza weighing about 100 grams contains 1.9 grams of salt.
Steiner continued: we eat so much salt in our food every day. Thats why reformulating the formula in the food supply is the most successful way to reduce salt intake across the country.
Experts also have different opinions on whether high salt intake can be offset by healthy diet and exercise. Some people, including Steiner, said a potassium-rich diet in fruits, vegetables, nuts and dairy products helped offset the negative effects of salt on blood pressure. Ceu Mateus, a senior lecturer in health economics at Lancaster University, suggests that we should give priority to hidden salt in our diet rather than trying to avoid it altogether. Our salt problem may be similar to the problem of low salt intake, but we still need to do more research to understand the problem, he said. At the same time, healthy people will be able to control the intake of salt. We should realize that too much salt is really bad, but dont eliminate it completely from your diet. Although recent studies have suggested that low-salt diets are potentially dangerous and that there are individual differences in salt sensitivity, it can be concluded from existing studies that too much salt increases blood pressure, and other findings remain to be verified. Source: NetEase science editor: Qiao Jun Jing _NBJ11279
Ceu Mateus, a senior lecturer in health economics at Lancaster University, suggests that we should give priority to hidden salt in our diet rather than trying to avoid it altogether.
Our salt problem may be similar to the problem of low salt intake, but we still need to do more research to understand the problem, he said. At the same time, healthy people will be able to control the intake of salt. We should realize that too much salt is really bad, but dont eliminate it completely from your diet.
Although recent studies have suggested that low-salt diets are potentially dangerous and that there are individual differences in salt sensitivity, it can be concluded from existing studies that too much salt increases blood pressure, and other findings remain to be verified.