We have all heard that intake of salt should be limited because it increases the risk of hypertension and cardiovascular diseases resulting from it. Now researchers have revealed another way salt can be tricky: if salt intake is high, you want to eat more, thus consuming more calories. The mechanism behind it is really curious.
Salt makes you hungrierAlthough it’s been known for a long time that consuming salty food makes you want to drink, it came as a surprise when researchers found that it also makes the consumer hungrier. A study carried out by an international team of investigators found that following a diet rich in sodium does not necessarily trigger thirst, but it urges to get another snack more often. Perhaps you noticed it yourself that it is much easier to eat, say, salted rice than unsalted. The same is true of snacks, and that is why junk food is so popular: it makes you crave it. The researchers asked a group of Russian cosmonauts training for their next mission to follow the diet they will be introduced. Instead of sticking to a healthy diet that does not imply high sodium intake (only 2,300 mg), they were told to eat food resulting in 3,500 and 4,800 mg of daily salt intake. The amount of calories remained the same. In order to compare the results afterwards, the investigators also conducted another study in which mice were used as models. They were surprised to see that contrary to the widespread belief, such dietary changes did not cause thirst in the cosmonauts. Instead, they reported being hungrier more often. The mice also started consuming more food once the salt intake was increased. Both groups (the rodents and the men) drank less water than normally, which was another surprising finding, but the finding that was especially weird was that despite decreased water intake the urine output increased.
The mystery of extra urineIt was unclear what the cause of this increased urine output was, so they looked at what processes were stimulated in the body as a result of eating food rich in sodium. It appeared that as the body did not need that much sodium, it tried to expel it. To do it, the body needs water, which is scarce, provided that water intake was decreased. In order to eliminate the chemical, it had to break down its own muscle and fat cells to get water to process the extra sodium. The mechanism behind it uses glucocorticoid, the level of which increases as more and more sodium is getting into the bloodstream. It triggers the processes of breaking down muscle tissues and fat cells, and losing them makes a person hungrier.
Not a good way to lose weightAlthough many readers are likely to think that foods rich in sodium can become a good means of losing weight, such an approach would definitely be dangerous, and here’s why. First, fat cells are not the only thing being lost: muscles are broken down too, which is not beneficial. Second, high levels of glucocorticoid are associated with diabetes and other diseases. Third, the good old advice to avoid high sodium intake to try to prevent hypertension is still valid. And finally, even if you think you can cope with all these adverse effects, you will still consume more food to compensate for the calories lost in the course of eliminating salt from the body. Another reason not to think about losing weight this way is that salty food is generally rich in calories, and those French fries and chips are going to hurt your liver, as well as other organs. If you want to lose weight, exercising and a healthy diet will be a much better option!
High salt intake reprioritizes osmolyte and energy metabolism for body fluid conservation – Jci.org
High salt intake associated with doubled risk of heart failure – Escardio.org
Health Risks and Disease Related to Salt and Sodium – Hsph.harvard.edu