And we come to a rather controversial study, which links a diet rich in salt, with triple the recommended daily allowance, therefore 15 grams of table salt per day, to the risk of dementia.
WHAT HAPPENS IN THE BRAIN WITH A DIET RICH IN SALT
The study, conducted by the Department of Neurology at the Knight Alzheimer’s Disease Research Center in Washington and appeared in the journal Nature , was conducted on a group of mice. The researchers found that the mice fed a salt-rich diet showed signs of dementia, and that the neurons’ Tau protein was mutated. This mutation is also a phenomenon linked to Alzheimer’s in men.
The mechanism by which this happens is intestinal and then cerebral.
Researchers refer to it as a domino effect.
Too much salt promotes the formation of an inflammatory substance, interleukin 17. This in turn accumulates in the blood, causing blood vessels to narrow by reducing nitric oxide levels. In the brain, vasoconstriction and nitric oxide reduction would change the Tau protein. This mutation is at the origin of taupathy, or dementia. However, something is wrong.
DOUBTS IN THE STUDY ON A DIET RICH IN SALT
In fact, until now, studies on nitric oxide claimed exactly the opposite. In 1997, at the third International Symposium on the Neurobiology and Neuroendrocrinology of Aging, Dr. Mc Cann showed that nitric oxide was related to premature aging. Dr. Mc Cann started from two studies, also on mice, in which it was shown that nitric oxide, acting as a free radical and causing vasodilation, led to rapid aging of the organs.
In 2005 , Dr. Mc Cann published new scientific evidence, which correlated nitric oxide with increased body fat and not just with premature aging.
So basically we have two different hypotheses, one contrary to the other.