It’s safe to say that salt is one of the most popular spices on the planet. But the latest research shows that if you overindulge, it’s not only your heart that will suffer. You could be doing harm to your brain.
Now, when I say “overindulge,” I’m not talking about going too heavy with your saltshaker at meals. That represents just a drop in the proverbial bucket of your salt intake. Studies show that most of the salt Americans consume is already added to foods by manufacturers before we buy them.
And, if you eat a lot of processed foods which have huge amounts of salt added to them, chances are your cells may be swimming in excess quantities of salt. And that has dementia researchers worried.
Last year, when researchers at Georgia State University decided to study how parts of the brain respond to internal changes in the body, they focused their sights on the hypothalamus. The hypothalamus is located deep inside the brain and takes part in regulating body temperature and reproductive functions, as well as being involved in controlling your urge to eat or drink.
The Georgia researchers say they picked salt as a stimulus because this brain section helps the body respond to shifting salt levels.
“We chose salt because the body needs to control sodium levels very precisely. We even have specific cells that detect how much salt is in your blood,” says researcher Javier Stern, M.D., PhD. “When you ingest salty food, the brain senses it and activates a series of compensatory mechanisms to bring sodium levels back down.”
In fact, the body lowers its salt levels when neurons in the hypothalamus are activated that set off the release of vasopressin, a hormone that stimulates the body to hold on to more water.
But what shocked the researchers was that this activation led to less blood flow to the neurons. In past research, neuronal activation had always been accompanied by increased blood flow.
Cutting Off the Oxygen Supply to Brain Cells
“The findings took us by surprise because we saw vasoconstriction, which is the opposite of what most people described in the cortex (the outer part of the brain) in response to a sensory stimulus,” says Dr. Stern. “Reduced blood flow is normally observed in the cortex in the case of diseases like Alzheimer’s or after a stroke or ischemia.”
The reduction in blood flow cuts off much of the supply of oxygen to the neurons – a condition known as hypoxia.
“If you chronically ingest a lot of salt, you’ll have hyperactivation of vasopressin neurons. This mechanism can then induce excessive hypoxia, which could lead to tissue damage in the brain,” warns Dr. Stern. “If we can better understand this process, we can devise novel targets to stop this hypoxia-dependent activation and perhaps improve the outcomes of people with salt-dependent high blood pressure.”
Disrupts Your Immune System
Unfortunately, the recently discovered health issues surrounding our current salt overuse don’t stop with the brain.
Researchers in Germany have produced evidence that large helpings of salt can also disrupt the mitochondria in immune cells. And since mitochondria are the energy-producing organelles that keep immune cells (and all other cells) functional, this interference, the scientists say, can throw a monkey wrench into the immune system’s ability to keep inflammation under control.
According to the German studies, large amounts of salt at a single meal disrupt the immune system, as does a diet that continuously results in an overly large salt intake. In one part of the research, the scientists found that a serving of pizza that contained ten grams of salt disrupted a person’s immune cells’ mitochondria for somewhere between three and eight hours.
In the next part of their research, the scientists plan to examine how salt affects the mitochondria in muscle cells and neurons.
“If such an important cellular mechanism is disrupted for a long period, it could have a negative impact – and could potentially drive inflammatory diseases of the blood vessels or joints, or autoimmune diseases,” warns researcher Markus Kleinewietfeld, PhD.
Moderate Your Salt Intake, But Don’t Go Salt-Free
Although large amounts of salt can cause health problems, studies also show that a very low salt or salt-free diet can lead to health problems.
For instance, researchers have found that a low salt diet can set off insulin resistance and, in the long term, can lead to high blood pressure.1,2 But the German scientists seem to believe that keeping salt intake to around six grams or even a bit less per day may be optimal.
Now, remember that the key to controlling salt intake is to limit processed foods. According to government figures, about 70 percent of Americans’ salt consumption is from fast food, meals eaten at restaurants, and the frozen and prepared foods bought at the supermarket. About six percent of a meal’s salt content gets added in food preparation in our home kitchens and only five percent is from the saltshaker. About 14 percent of salt content is just a normal component of food.
A good guideline to follow is to remember that a teaspoon of salt is about 2,300 mg, so about a teaspoon and a quarter of salt daily or up to a little bit less than three teaspoons is a reasonable range for a healthy adult.3