Lots of salty junk food stresses the brain
If you’re a sucker for salty snacks like I am, you probably know that high-sodium consumption can raise your blood pressure. Known as hypertension, high blood pressure is a major risk factor for stroke and heart disease, among other conditions. But a new study published in the November 11, 2022 edition of the journal Cardiovascular Research indicates that high amounts of salty, processed foods may also induce anxiety and aggression.
Understanding the research
Researchers at the University of Edinburgh’s Centre for Cardiovascular Science theorized that high salt consumption might elevate stress hormone production, impacting well-being.
To test their hypothesis, they fed male mice either a control, a low-sodium diet, or a high-salt diet. Then they took blood samples to assess the hypothalamic-pituitary-adrenal (HPA) axis, which serves as the body’s response system. They also analyzed tissue samples for genetic information about the heart, kidney, liver, and hypothalamus.
The scientists found that the mice who consumed the high-salt diet had increased glucocorticoids, hormones that help regulate not only the body’s stress response, but also cardiovascular, metabolic, immune, and cognitive functions. The mice who eat high-sodium diets also had hypernatremia (high salt levels in the blood) and fluid imbalance, which activated a water conservation response in the mice despite having free access to water.
“We are what we eat and understanding how high-salt food changes our mental health is an important step to improving well-being,” said lead author Matthew Bailey, Ph.D., professor of renal physiology at the University of Edinburgh’s Centre for Cardiovascular Science. “We know that eating too much salt damages our heart, blood vessels, and kidneys. This study now tells us that high salt in our food also changes the way our brain handles stress.”
Limitations of the study
Due to research limitations related to the pandemic, the researchers were unable to test their hypothesis on female mice. This is particularly important to note as both men and women show more of the stress hormone in their urine if they consume a high-sodium diet.
“There is also evidence that this stress system shows sex-different responses to stress,” explains Dr. Bailey. “In females, the rapid response is often larger, and over time, females have a higher risk of developing some types of stress-related psychiatric disorders. My hypothesis is that the effect of salt would be larger in females.”
What you can do
When you’re purchasing pre-made foods, be wary of ultra-processed foods, which are generally high in energy, fat, sugar or salt, and low in fiber.
When cooking at home or sprinkling your meal with salt, Dr. Bailey recommends opting for low-salt alternatives, such as sodium chloride or potassium chloride. Past studies have shown their effectiveness at decreasing sodium levels consistent with the FDA’s recommendations.
Wendy Burt-Thomas writes about the brain, mental health and parenting.
Check out the original research: