Salt: The paradoxical philosopher's stone of autonomic medicine

New paper on Salt: The paradoxical philosopher's stone of autonomic medicine - to expand intravascular volume or to raise blood pressure.

Highlights

• Salt has profoundly shaped human history, including diet and medicine.
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  Salt improves orthostatic tolerance but also increases risk of hypertension.
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  Although recommended by consensus, randomized controlled studies have not been done.
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  Salt also affects immune function, psychological state, and gut microbiota.
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  Long term treatment of POTS should include blood pressure monitoring.

Abstract
Sodium chloride, or common table salt, for millennia has played a prominent role in human affairs. Salt is also a key molecule for regulating intravascular fluid volume in patients with orthostatic disorders. In this first article of a special issue of the journal focusing on salt and the autonomic nervous system, the historical and physiologic significance of salt is reviewed, highlighting its importance to society and to medicine. The relevance of salt both for civilization and for autonomic physiology penetrates into nearly every aspect of life and health. Replacing salt that has been depleted or administering salt to expand intravascular volume is considered standard treatment for patients with orthostatic hypotension and syndromes of orthostatic intolerance. The potential long term effects of added salt, including effects unrelated to intravascular volume, have been insufficiently studied in patients with autonomic disorders. A salient concern is the potential increased risk of developing hypertension. Underappreciated aspects of salt include its ability to increase anxiety and through nonosmotic mechanisms to contribute to local tissue inflammation. Salt may be either salubrious or detrimental, or possibly both at the same time, depending on the clinical conditions. Reconciling these opposite effects in clinical practice requires weighing benefits against potential risks, assessing what is known alongside what is uncertain, and titrating treatment decisions to the particular needs of each individual patient.

https://www.autonomicneuroscience.com/article/S1566-0702(21)00125-9/fulltext

 

Someone might want to send the author this paper!

Effect of High Dietary Sodium Intake in Patients With Postural Tachycardia Syndrome
https://www.sciencedirect.com/science/article/abs/pii/S0735109721006306?via=ihub

 

This effect has been found to be very overblown in most people, and only applies to those who take a lot more salt than average.

https://www.acsh.org/news/2018/08/10/spoonful-salt-makes-blood-pressure-go-down-13289

Increasing potassium has been found to reduce blood pressure by relaxing arterial walls. It also has an impact on sodium/salt because it causes more sodium to be excreted.

And an n=1 experience of increasing salt intake :

Source for the above quote: https://stopthethyroidmadness.com/blood-pressure/

 

The JACC paper I mentioned looked specifically at POTS patients that were classified hyperadrenergic, i.e. the ones prone to bouts of upright hypertension.

There were no differences in blood pressure between the low salt diet and the high salt diet (18gm of salt per day!!) there either - but useful improvement shown in other metrics and some trend towards reduced symptom burden too.

 

I once went to a cardiologist because I was worried I had arrhythmia. I just had extra heartbeats, so that was fine, but he was concerned that my blood pressure was a little low. He told me to make sure I have enough salt in my diet, especially since I don't eat much processed food.

My main health care provider has also talked to me about eating enough salt. Her reason is that it helps support the adrenals, in addition to the other things I do for that. I add a little salt to each glass of water I drink.