Does salt make us “salty?” Excess levels found to increase stress by triggering evolutionary response
18 Nov 2022 --- High amounts of salt in diets can significantly increase corticosterone – the equivalent of corticosteroid, the so-called “stress hormone” in humans – a mouse model study has revealed.
Additionally, salt was found to double the hormonal response to environmental stressors. The UK-based research team behind the study reveals that consuming excessive amounts of the savory ingredient likely has the same effect on people.
Moreover, since high levels of salt and the stress hormone are associated with high blood pressure and increased incidences of stroke and heart attacks, reducing the amount of salt in diets could have an exponential effect on heart health and life span.
“Every day, we eat about 20 times more salt than our body actually needs,” Dr. Matthew Bailey, co-author of the study and a professor of renal physiology at the University of Edinburgh’s Centre for Cardiovascular Science, tells NutritionInsight.
“We know that we eat too much salt and most of the public health messaging is around blood pressure and heart attacks. Our study shows that [salt-related] bad health problems are more extensive and long term are likely to make changes to our body that make us less healthy and less able to deal with stress.”
In essence, the study shows that higher levels of salt intake may place a person in a constant state of “fight or flight,” increasing the stress response and perceived stress levels.
The researchers state that they hope the findings of this study will “encourage a review of public health policy around salt consumption, with a view to manufacturers reducing the amount of salt in processed food.”
Fight or flight
According to the study, the recommended amount of salt for adults is less than 6 g per day, but most people consume around 3 g more than that on average.
Though the effects of excessive salt on the heart and circulatory system are well-known, the researchers note that the impact of salt on behavior has not been well researched.
In order to test the effects on the body’s stress system, experts from the UK’s University of Edinburgh gave a high-salt food diet – equivalent to the typical salt intake of humans – to mice and monitored their corticosterone levels for periods of two to eight weeks.
“Our study used mice to see what effect this had on one of the body’s main stress response hormones,” Bailey underscores. “We found that when salt intake increased, the resting level of the stress system was turned up – a bit like using a dimmer switch to turn up the lights or turning up the volume on the TV – and it stayed up as long as high salt intake was maintained.”
“We also tested the response of the system to an external, environmental stress: the hormone response to stress was much higher when mice were eating salt-rich food.”
Bailey further explains that, though stress hormone is good in the short-term when it helps the body adapt to stressful situations and is part of a normal response to stressful situations, it can also cause problems when that system is “turned up” for long periods of time.
“In this situation, elevated stress hormones can cause immunosuppression, obesity, insulin resistance (Type 2 diabetes) and can also change sleep behaviors and mood,” he explains.
“Keep calm and carry on”
The study, published in Cardiovascular Research, also further states that more research will need to be done to see if high salt intake affects other behaviors, such as anxiety and aggression.
The researchers hold that this may be possible since the salt activates the release of adrenocorticotropic hormone from the pituitary, which triggers the adrenal glands, initiating the fight or flight response.
“The study in mice shows that salt causes the system to become activated long term, and there are studies in people pointing to the same thing,” says Bailey. “The main dangers are that it may cause health problems like high blood pressure as well as changes to mood, making the stress system less effective.”
Bailey concludes by stating that excessive salt is “overall bad for your health.”
By William Bradford Nichols
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