Yet another myth about this misunderstood mineral has been debunked
When you eat a salty meal, it’s pretty much a given that you’re going to chug a bunch of water afterward. We’ve all heard that salty stuff makes you thirsty, so naturally you’re more inclined to load up on the H2O after having a bunch of the mineral. (Here’s the best way to keep salt in your diet, though.)
But, bizarrely, no one has ever studied the connection to see if having a lot of salt makes people drink more—until now.
In a new study published in the Journal of Clinical Investigation, a team of scientists carried out a simulated mission to Mars and found that astronauts who consumed more salt retained more water than their less salty peers and weren’t as thirsty.
The Mars tie-in may seem kind of random, but researchers point out that if you’re on a long journey to space, it’s important to figure out in advance how much water you’re going to need. And, if you’re going heavy on the salt and drinking a bunch of extra water as a result, you could run out of water before you make it back home.
For the study, scientists took two groups of 10 male volunteers and put them in a mock spaceship for two simulated flights to Mars. The first group “traveled” for 105 days, while the second journey took more than 205 days. People in each group ate pretty much the same thing, but they were given different levels of salt in their food over several weeks.
When the “astronauts” ate more salt, they peed more, which didn’t shock scientists. After all, they had thought that salt essentially grabs water in your body and drags it into your pee, leaving you feeling dehydrated and thirsty in the process. But researchers discovered that all that extra peeing wasn’t because the participants drank more water—the extra salt people ate set off a mechanism to conserve water in their kidneys.
Researchers took their findings to a mouse study and found that the process of conserving water in your kidneys takes a lot of energy, i.e. calories, and makes you hungrier in the process. They stacked those findings up against the fact that astronauts on a salty diet complained that they were hungry and concluded that having a salty diet actually makes you hungrier, not thirstier. Since people often confuse hunger for thirst, it’s not a total shocker that this is what’s actually going on.
This doesn’t give you a pass to eat the processed foods that can boost your sodium levels well past the daily recommended limit, but, as we’ve pointed out in the past, a sodium-rich diet isn’t necessarily a bad thing for healthy men. And, in fact, a 2014 study in the Journal of Hypertension found that too little salt in your diet can result in adverse effects, including higher heart rates and risk of diabetes. Their recommended range was 2,645 to 4,945 milligrams a day, compared to the American Heart Association’s 1,500 milligram limit.
Other studies have also shown that too much salt can lead to feeling less full while you’re eating which, in turn, results in you consuming more calories. And JCI‘s study also pointed out that, while salt intake doesn’t make you thirsty, “salt-driven changes in energy metabolism may link high salt intake with diabetes mellitus, osteoporosis, and increased cardiovascular and neurovascular disease risk.”
The key here, as always, is balance, and knowing what your body needs to maintain a healthy level of sodium. In any case, you now know that too much of isn’t what’s fueling your thirst.