Yet another “controversial” topic is getting some attention. After medicine reluctantly accepted the existence of the “Obesity Paradox“, now attention may be shifting towards the “Salt Paradox“. Speaking of which, how many people even know there was such a think as the “Salt Paradox”? Yeah, I bet not many. Yet, the fact that lowering salt intake is robustly associated with increased all-cause mortality and morbidity, has been known to medicine for decades. How many times have you heard about the amazing benefits of salt from your doctor or public health authorities? Yeah, I bet that number is zero for most people. In any event, while there have been many attempts to explain the “Salt Paradox”, the most plausible explanation to date has been the fact that lowering salt increases aldosterone (the sodium-retaining hormone) and elevated aldosterone has been implicated in quite a few chronic, degenerative conditions such as cardiovascular disease (CVD), kidney disease (CKD), chronic inflammation, neurological diseases, fibrosis, and even cancer. Conversely, some of the most successful drugs on the market are aldosterone antagonists. Maybe I am just weird, but I find it quite perverse to spend billions on aldosterone antagonists every year, when the underlying issue can easily and cheaply be corrected by increasing salt intake (or at least avoiding restricting it).
Be that as it may, there is now evidence that salt restriction may not only be contributing to the stress response (HPA axis) but severe sodium restriction (as advocated by most doctors for people with blood pressure, diabetes, CVD, CKD, etc) may be able to trigger the stress response “de-novo” – i.e. in the absence of any stressful external/internal stimuli. How does salt restriction achieve that “feat”? Simple – by elevating cortisol levels. Now, the study found that restricting salt intake decreased urinary cortisol excretion and this is what led to increase in the blood cortisol concentrations. However, I am not convinced this is the whole story considering the fact that salt restriction is known to increase adrenaline release (a known stimulator of ACTH and thus cortisol), and such it is likely that the elevation of blood cortisol was due to sodium restriction both increasing cortisol synthesis/release from adrenals and decreasing cortisol excretion. Once again, what we are told by medicine is healthy (e.g. salt restriction) turns out to be anything but.
https://doi.org/10.1016/S0039-128X(98)00015-4
https://insight.jci.org/articles/view/127530
https://pubmed.ncbi.nlm.nih.gov/32511774/
https://www.zerohedge.com/medical/low-sodium-diet-may-be-stressing-you-out
“…A study published in Clinical Endocrinology in 2020 showed that an increase in salt consumption leads to a rise in cortisol levels in your urine and lower cortisol levels in your bloodstream. What does this potentially mean? Restricting your sodium intake may lead to higher levels of circulating cortisol.”
“…A study published in The Journal of Clinical Endocrinology and Metabolism in 2003 stated, “In healthy subjects, dietary salt loading increases and sodium restriction decreases urinary free cortisol excretion” and “changes in cortisol metabolite excretion after salt loading were accompanied by a decrease in plasma cortisol concentration.” Prior to that, a 1998 study concluded, “This study supports the notion that sodium restriction decreases urinary cortisol excretion.”
