Salt, or sodium chloride, is one of the most common ingredients of any food and it has become common knowledge that too much of it is not a good thing – especially if you have high blood pressure. It does seem to make sense because the theory is that if one consumes a lot of salt, you’ll start drinking a lot of water in order to compensate for the increase of salt in the bloodstream as your body requires a certain balance within (homeostasis), otherwise your organs will not function properly. As such, the increase amount of water would mean an increase in urine production in order to remove the access salt. However, a new discovery may prove this theory all wrong, and it might even cause us to switch the way we think about how our body deals with high intake of salt.
Dr Jens Titze, a kidney specialist at the Vanderbilt University Medical Center and the Interdisciplinary Center for Clinical Research in Erlangen, Germany, discovered that not only does a higher intake of salt makes patients less thirsty, it’ll also make them hungrier.
In his two latest research papers, Titze explains how he came to this discovery. It all started with a class on human physiology back in 1991, where the professor talked about an experiment that the European Space Programme did to see how subjects made to live in a small capsule over a 28-day period would get along in insolation.
While the experiment was done to find out more about human physiology in insolation, Titze noticed something interesting. It seemed like the patients’ amount of urine weren’t correlating to their increased sodium intake. You would think that subjects with a high sodium diet would consume more water and therefore produce more urine but this was not the case.
He noticed something similar in another isolation experiment held in 1994 by the Russian Space Programme. Once again, Titze studied the urine levels of the subjects living on a high sodium diet and once again, he found that an increased level of sodium did not cause an increase in urine volume from the subjects.
Titze’s discovery culminated with a series of experiments held in 2006 – one lasting 105 days and the other 520 days. Cosmonauts that formed part of the research were given diets with varying levels of sodium that changed with each day; this gave Titze a chance to finally figure out what really goes on in the body when high amounts of salt is consumed.
He realised that although the subjects were drinking more water when consuming high sodium diets, the volume of urine was the same as compared to those on a low sodium diet. Naturally, there was a higher amount of sodium found in the urine but what was more significant was the increased amount of urea excreted by those on a high salt diet.
That wasn’t the only thing the scientists observed. They also realised that subjects seemed to get hungrier when the sodium intake was higher, this seems to point to higher levels of glucocorticoid hormones released which increased the subjects’ metabolism rate.
Titze and his team decided to hold further research by doing similar tests with mice, where the test group were fed more salt and given less water to see if the effects correlated with what he had seen during the isolation experiment.
He realised that even though the animals weren’t receiving water, the levels of glucocorticoid hormones in their system caused their body to release water from the fat and muscle in their bodies.
It was an effect akin to what happens when you’re low on nutrients, and your body starts using its stored resources. This was also the reason why the mice and the cosmonauts on high sodium diets ate 25% more food: their bodies were telling them to eat more in order to gain more nutrients.
Dr Mark Zeidel, a nephrologist at Harvard Medical School, compared this process to what camels do when they’re in the desert and low on water – their body metabolises the fats in their hump. Zeidel also commented that this discovery on salt and metabolism could prove salt’s involvement in weight loss.
However, Titze does not recommend trying to lose weight by eating a lot of salt, because besides burning fats for energy, high salt intake actually makes one want to eat more. To add to that, the higher levels of glucocorticoid hormones within the body can lead to the development of Type 2 Diabetes.
It seems like there’s still a lot more we can learn when it comes to the effect that sodium has on our bodies and health, but in the meanwhile, just eat the amount of salt that your doctor recommends!
Photo Credits: The Alternative Daily, The Inquisitive Eater, Reader’s Digest