01/24/2015 10:10 am ET Updated Jan 24, 2015

The Scary Way Excessive Salt Intake May 'Reprogram' The Brain

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There are many health reasons to lay off the salt, from fluid retention to an increased risk over time of developing high blood pressure, heart attack and stroke.

While the link between sodium and hypertension is nothing new (thought some scientists say it is overstated), the precise mechanisms by which sodium can raise blood pressure have been less clear.

According to new research from McGill University, too much sodium may actually "reprogram" the brain in a way that interferes with a process that normally keeps the body's arterial blood pressure at a healthy level.

"We found that a period of high dietary salt intake in rats causes a biochemical change in the neurons that release vasopressin (VP) into the systemic circulation," one of the study's authors, Dr. Charles Bourque of the McGill University Health Centre, said in a university press release. "This change, which involves a neurotrophic molecule called BDNF (brain-derived neurotrophic factor), prevents the inhibition of these particular neurons by other cells."

The researchers found that high salt intake prevents the inhibition of VP neurons, which normally occurs through a bodily system that detects pressure in the arteries. When this safety mechanism has been disabled, blood pressure is more likely to rise when sodium is increased in high levels over time.

However, other data suggests that we shouldn't be too worried about sodium. A large-scale study published this week in the journal JAMA Internal Medicine found that higher sodium intake was not correlated with a higher risk of mortality.

The findings were published in the journal Neuron.



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