Discussions about the effects of salt on our bodies are typically focused on heart health. But there are plenty of theories and studies to suggest that the chips and treats we love could be impacting our brains, too.
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In 2015, researchers at McGill University in Montreal, Canada, found that too much salt appeared to reprogram the brains of lab rats. In a new study, published this week in Nature Neuroscience, scientists have found that too much salt could make changes in the gut that impact cognitive function.
For the study, researchers fed mice a diet high in salt, which would be comparable to the amounts found in diets of people who eat too much sodium. After two months, the team used an MRI, magnetic resonance imaging, to look at the animals' brains and found there was less blood flow in the cortex and hippocampus, two areas important for learning and memory. They also found that mice who were given high salt diets performed poorly on maze tests compared to those who did not.
What's more, researchers found that the effects could be reversed once the mice went on their regular diet not laced with salt.
Additionally, they also found that the excess salt appeared to cause an immune response as though the body was protecting against an invader, like a virus or bacteria. "It's reacting to the presence of the salt as if it's something to fight against," Elizabeth Hillman, a biomedical engineer at Columbia University's Zuckerman Institute, told Newsweek. She did not take part in the study but wrote a review of the research for the journal.
Hillman explains that a subset of white blood cells seemed to increase when too much salt was present in the gut. This spike also boosted production of proteins, called IL-17, that helps regulate immune and inflammatory responses. As these travel through the body and come into contact with the blood vessels in your brain, the amount of nitric oxide produced in the brain diminishes. Nitric oxide is important for our organs to work properly and changes the level of blood flow and reactivity in our brains, which could explain why the mice who ate a lot of salt weren't as sharp mentally.
According to Hillman, this new study was incredibly thorough.
"I think it constitutes an enormous amount of careful work," she said.
She believes this new research could possibly help find new medications that boost brainpower or different uses for current treatments used for other ailments.
"We have hundreds and hundreds of drugs already made that we take everyday that target these blood vessels," she said.
She does caution that there needs to be much more research done before any link can be made between dementia and high-salt diets, though she believes only good can come from adopting a lower sodium diet.
"I don't feel too bad jumping to conclusions," she said. "Antioxidants, healthy diet, exercise—none of those things can be bad."
Uncommon Knowledge
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
About the writer
Melissa is a science writer covering health for Newsweek and has contributed to Inc., Dr. Oz The Good Life, Men's Fitness, Marie Claire and others. She earned ... Read more
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