EXCESS SALT HARMS THE BRAIN
BY STEVE BORN
The research was published nearly a year ago, but itsmessage remains unchanged and vitally important:
High salt diets can have seriously negativeeffects on a number of areas of brainfunction, leading to an increased risk ofcerebrovascular diseases and dementia.
This particular study was conducted by researchersfrom Weill Cornell Medicine in New York, who usedtwo groups of mice for this study. One group had a dietthat was comprised of 4% salt, and the other group'sfood content consisted of 8% salt. According to theresearchers, these amounts represented an 8- to 16-fold increase in salt compared to a normal mouse diet,with the higher amount (8%) being comparable to ahigh-salt diet for humans.
After an 8-week period, the researchers used MRIimaging to photograph and analyze the anatomy andphysiology of the mice's brains. The negative resultsthey found were astounding:
- A 28% decrease drop in blood flow in the cortex, the partof the brain associated with thinking and processinginformation from the five senses
- A 25% blood flow drop in the hippocampus, the area of thebrain responsible for processing emotional responses andlong term memory
The mice on the higher-salt diet were shown to havea dramatic decrease in the production of nitric oxide,resulting in impaired blood flow in the brain. Thistranslated to the mice developing dementia, as theyperformed poorer than the other mice on tests suchas object recognition and navigating through a maze,while also spending less time gathering materials (andfewer materials) for building a nest.
Interestingly, this decline occurred in the high-salt dietmice regardless of blood pressure. Lead researcher, Dr.Costantino Iadecola, states: We discovered that micefed a high-salt diet developed dementia even whenblood pressure did not rise. This was surprising since,in humans, the deleterious effects of salt on cognitionwere attributed to hypertension.
What Dr. Iadecola and colleagues discovered was thehigh-salt diet increased levels of a protein known asinterleukin 17 (IL-17), whose job is to regulate immuneand inflammatory responses. However, when levels ofIL-17 are too high, that can decrease the productionof nitric oxide, which affects brain functions. It shouldbe noted that by discontinuing the high-salt diets andadministering IL-17-lowering drugs, Dr. Iadecola wasable to reverse this negative process in the mice.
Based on this study, it's clear that excess salt leads to levelsof IL-17 that are too high, which can disrupt and even destroymany functions of the brain.
Just as alarmingly, if notmore so, elevated IL-17 levels are also associated withmany other inflammatory diseases such as asthma,Crohn's disease, inflammatory bowel disease, multiplesclerosis, rheumatoid arthritis, and more.
According to the Centers for Disease Control andPrevention (CDC), 90% of children and 89% ofadults in the US - irrespective of age, race, gender orhaving high blood pressure - consume more than therecommended limit of 2,300 mg a day for sodium. Mostof that sodium comes from salt, but does not includesalt added to food while eating.
A massive amount of research shows that excesssodium (salt) is not beneficial for exercise performanceand, even more importantly, is harmful for health. Toperform at your best athletically, and to help stave offthe detrimental health effects of too much sodium, theanswer is abundantly clear: Cut back on yoursalt intake!View PDF