For years, salt has been linked to high blood pressure. At present, studies show that it may also harm your brain.
The newest research was conducted to determine the link between high-salt diet and memory and thinking problems. It uses mice as a subject of the study. There were also earlier researches on humans that recommends a link between brain health and high-salt diets as well.
In their diet, the mice were fed either 8 or 16 times the normal amount of salt. Within 8 to 12 weeks, the mice showed signs of thinking and memory problems like trouble in telling new and familiar objects apart, inability to build a nest and find it harder getting through mazes. All these behaviors are part of a mouse’s interaction world.
Constantino Iadecola, MD, a professor of neurology and neuroscience at Weill Cornell Medical College in New York City and the lead researcher of the study states that:
“We translate that in humans to activities of daily living, and that’s what we would call severe cognitive impairment or dementia.”
For humans this means, disorientation, having memory problems, and not able to pay bills, cook, dress or do the usual everyday routine.
Iadecola further says that the amount of salt they fed the mice was likely 5 to 6 times the salt in a usual American diet. However, he stated that:
“No one knows exactly how much salt Americans eat, because most of it is hidden in processed foods or restaurant foods. I’m sure it’s grossly underestimated.”
Additionally, the same level of impairment was shown by the mice no matter which of the two high-salt diets they ate. That leads to a conclusion that less salt could also cause the same problem.
As added by Iadecola:
“I suspect that you can get cognitive impairment from even lower levels than we used.”
A neurologist named Pinky Agarwal, MD, who specializes in movement disorders like Parkinson’s disease, says that this study could change the conversion of diet with her patients. When it comes to salt and patient health, doctors focus only on hypertension, high blood pressure, stroke and cardiovascular diseases. This study would give enough reason for everyone to think about salt intake.
What Salt Does?
It revealed that when the mice ate the doctored food, the excess salt causes a response in their small intestines thus, resulting to a production of large amounts of Th17, which is a type of white blood cell involved with the immune system. This further causes a rise in the level of the protein called IL-17, which is another component of the immune system.
This problem faced by mice is would likely to happen in human. Once our body produces too much IL-17, it will fail to supply enough nitric oxide, which is made by cells lining blood vessels. When the level of nitric oxide drops, your blood vessels can’t relax and this will lead to less blood flow to the brain.
David Hafler, MD, a professor and chairman of neurology and professor of immunobiology at the Yale School of Medicine says:
“This shows that dietary influences may be a major influence in vascular dementia.”
The importance of this new study was supported by Hafler’s own research in 2013, which showed that excess salt boost levels of Th17 and influence the development of sclerosis. This discovery may further explain the rise in MS as well as other autoimmune diseases like rheumatoid arthritis, psoriasis, and inflammatory bowel disease.
In countries where people eat a lot of salt, studies have shown higher rates of dementia and stroke, according to Iadecola.
Canadian researchers also found out that adults who seldom exercise are at a higher risk of having memory and thinking problems if they ate a high-salt diet. This was reported las 2011.
Another study published in March 2017, also had found a link between low-salt diets and worsening thinking skills among adults over 50.
Effects May Be Reversible
If you are a salty food lover, then here’s the good news. Once returned to a normal diet, the brain function of the mice returned to normal. This suggests that, once you cut back your intake, problems caused by too much salt may be reversed,
In the study, high salt-diet where given to the mice for only 3 months. Is there a certain point at which the brain will suffer permanent damage? Iadecola answers:
“We don’t know what will happen if you do this for 10 years. My suggestion is that because the blood flow is reduced in the brain and because then the blood vessels in the brain don’t work correctly, something major is going to happen if you keep this up. … Watching salt intake may be an important step to preventing dementia.”