A study found the excess sodium reduced blood flow in the brains of mice—even when their blood pressure didn't rise.
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The United States Department of Agriculture recommends consuming no more than 2,300mg of sodium per day, but about 90 percent of American adults consume much more.

A recent study by scientists from Weill Cornell Medicine found mice that followed a high-salt diet experienced reduced blood flow to the brain, eventually leading to dementia.

The study, published in the journal Nature Neuroscience, examined mice who were fed a diet consisting of 4 percent or 8 percent salt—comparable to the high end of an American adult's salt consumption.

After eight weeks, researchers performed an MRI, and found that mice eating a higher-salt diet had less blood flow to two specific regions of the brain, the cortex and hippocampus, both essential for learning and memory.

Mice who followed this diet also performed worse on recognition tests, maze tests, and nest building, which the researchers determined was caused by the development of dementia.

Dr. Costantino Iadecola, senior author and director of the Feil Family Brain and Mind Research Institute and the Anne Parrish Titzell Professor of Neurology at Weill Cornell Medicine spoke to Cornell Chronicle, saying, “We discovered that mice fed a high-salt diet developed dementia even when blood pressure did not rise. This was surprising since, in humans, the deleterious effects of salt on cognition were attributed to hypertension.”

Researchers followed with additional experiments that found the mice developed an adaptive immune response in their guts, which boosted the production of a protein that regulates immune and inflammatory responses.

There is some hope for further research that came out of this rodent study. Scientists discovered when mice were taken off the high-salt diet, they were able to reverse the blood flow blockage. In addition, mice were treated with a drug known to reverse the gut issues, which was able to improve their behavioral and cognitive functioning.

Further research is needed in these areas to determine opportunities in solving health concerns from high-salt diets.