ME Association funds development of new protocol for Dysautomnia

[Jonathan Edwards]

“Your body responds to excess sodium by holding on to water to dilute the sodium. As a result, the amount of fluid in your blood vessels increases. That raises the pressure inside your blood vessels and makes the heart work harder.”

That sounds like straight nonsense. It looks as if you are quoting from some Harvard health advice page. Presumably it has been dumbed down out of all physiological recognition.

I am not sure how solid the evidence is for a causal effect of high salt intake on blood pressure. High salt intake is very likely to be associated with high cholesterol, sugar and meat intake and obesity. Studies have probably controlled for obesity but I doubt we have clear evidence for the salt actually causing a rise in BP.

Even if it does, that is something quite different from increasing blood volume and probably not associated with it. In normal people I strongly suspect that high salt intake makes no difference to blood volume (as quoted in the study mentioned above). That odd ting is that the renin angiotensin system that put B up is designed in part to retain salt if I remember rightly. So eating a lot of salt should lower angiotensin levels. Some of the best antihypertensives are angiotensin blockers so it doesn't easily add up.

All of this leaves the question of whether people with low blood pressure as in orthostatic hypotension do better eating more salt - again a different question because it is about the effect of salt specifically on a dysregulated volume control system. It would be interesting to now what renin levels are like in people with OI of various sorts.

 

[Kitty]

All of this leaves the question of whether people with low blood pressure as in orthostatic hypotension do better eating more salt

I got the impression it did help. But adding salt to your meals tends to make you want to drink more, so it could just as well have been that.

 

[livinglighter]

Are you saying that increased salt intake in the general population is not linked to high blood pressure through mild hypervolemia, and this type of information is incorrect? Presumably healthy people consuming high-salt foods get thirsty and take in extra fluids.

E.g.

“Your body responds to excess sodium by holding on to water to dilute the sodium. As a result, the amount of fluid in your blood vessels increases. That raises the pressure inside your blood vessels and makes the heart work harder.”

https://www.health.harvard.edu/heart-health/dietary-salt-and-blood-pressure-a-complex-connection

I see this simple connection has been questioned:
https://www.medicalnewstoday.com/articles/317099

All of this leaves the question of whether people with low blood pressure as in orthostatic hypotension do better eating more salt - again a different question because it is about the effect of salt specifically on a dysregulated volume control system. It would be interesting to now what renin levels are like in people with OI of various sorts.

I was under the impression it helps because the Autonomics lead at a well-known neurology hospital recommends increasing salt intake to address low blood volume as well. It seems odd that the medical advice is baseless.

 

[JemPD]

It seems odd that the medical advice is baseless.

Why? Its outrageous when medical advice is baseless, but there's plenty of that going around.
Treatment for CFS in the UK is almost entirely baseless, currently.

Not saying anything about salt intake etc, i wouldnt know, just that i dont trust any medical advice to be based on sound science these days

 

[Jonathan Edwards]

It seems odd that the medical advice is baseless.

It may seem odd but it is worth remembering that although there have been physicians and hospitals for centuries almost all medical advice was baseless until around 1970 - apart from Caesarian section after sepsis was understood and penicillin around 1945.

When I first started medicine all sorts of advice was still baseless. Almost all physio advice is baseless.

My impression is that pretty much all advice around 'dysautonomia' is hot air. I am not aware of any proper trials having been done.

 

[livinglighter]

Why? Its outrageous when medical advice is baseless, but there's plenty of that going around.
Treatment for CFS in the UK is almost entirely baseless, currently.

Not saying anything about salt intake etc, i wouldnt know, just that i dont trust any medical advice to be based on sound science these days

The field of CFS research and medicine is significantly underfunded and neglected, with psychosomatic medicine taking the forefront. I am uncertain if the same issues are present in Autonomics research and medicine, but there should be a higher standard for the scientific basis of medical advice given to patients.

I cannot definitively state that salt intake increases blood volume. I am emphasising that if some of the current medical advice provided by prominent figures in the field is poorly supported by evidence, it is important to gain a better understanding of the reasons behind this.

 

[voner]

@Jonathan Edwards, thanks for your enlightening replies. I am always learning about physiology from your statements.

here is what appears to be a UK charity just set up for warning about salt consumption by humans…

Action on Salt
Wolfson Institute of Population Health
Queen Mary University of London

https://www.actiononsalt.org.uk/resources/posters/

 

[Jonathan Edwards]

I cannot definitively state that salt intake increases blood volume. I am emphasising that if some of the current medical advice provided by prominent figures in the field is poorly supported by evidence, it is important to gain a better understanding of the reasons behind this.

That's fairly easy. Doctors bullshit all the time. They are trained to bullshit - to sound knowledgeable. It is supposed to inspire confidence.

'Prominent figures in the field' often turn out to be people pushing a line. They are not necessarily prominent in the medical community as a whole. I never came across anyone 'prominent' in autonomic research. But it is easy enough to find physicians who write dozens of clinical papers about autonomic problems without much scientific content.

 

[livinglighter]

It may seem odd but it is worth remembering that although there have been physicians and hospitals for centuries almost all medical advice was baseless until around 1970 - apart from Caesarian section after sepsis was understood and penicillin around 1945.

When I first started medicine all sorts of advice was still baseless. Almost all physio advice is baseless.

Agreed.

My impression is that pretty much all advice around 'dysautonomia' is hot air. I am not aware of any proper trials having been done.

I was not aware of the lack of proper trials. It's a dilemma that patients encounter in medicine: should one refuse medical care because of inadequate evidence or follow instructions in the hope that their health will improve based on what is likely to be supported by clinical evidence? The clinical evidence for CFS is considered to be poor, with patients sharing experiences of harm endured. Is the clinical evidence or wherever else these clinicians and researchers are getting their ideas from, as equally poor in other fields where it seems patients are not suffering as adversely from the medical advice they receive? It doesn't come across as a lot of medicine is at a standard that one hopes it would be.

 

[Jonathan Edwards]

Is the clinical evidence or wherever else these clinicians and researchers are getting their ideas from, as equally poor in other fields where it seems patients are not suffering as adversely from the medical advice they receive?

The standard of evidence and practice varies greatly according to how common a problem is and how easy the problem is to understand. Giving insulin for diabetes is based on a lot of good evidence, although it has taken decades for doctors to work out the best way to use it and when I was a student we gave about fifty times as much as needed in acute situations.

The standard of evidence is particularly poor for relatively uncommon conditions and for conditions where physiology is not well understood. ME/CFS is relatively uncommon as compared to coronary heart disease or stroke or cancer. Autonomic failure is also uncommon and although it is relatively well understood in late diabetes or rare syndromes like Shy-Drager, much of the time it is very unclear what is thought to be wrong.

Autonomic failure leads to heart rate changes, gut changes and circulatory changes in the legs in particular. But 'autonomic experts' often deal with quite different things like so-called PoTS. In PoTS the autonomic system seems to be responding well. The question is why it is responding in an unpleasant way, if indeed that is the problem . We have an excellent thread on all the uncertainties about PoTS.

If there was autonomic failure behind OI I do not see why eating salt should help. But very likely OI in ME/CFS or 'PoTS' is not related to autonomic failure. It comes across to me as all very confused and when I read papers about these things they look pretty naive and ungrounded to me. Doctors constantly thin they understand enough physiology to predict what treatments will help. What was shown unequivocally in research into intense care regimens in the late twentieth century is that no way can you predict. You have to test things out. Treatments that everyone thought must be good turned out to be bad.

And if Harvard puts out a dumbed down account about salt and blood pressure of the sort posted it seems likely that pretty much everyone in the field is talking hot air.

 

[Mij]

Do all people with OI have low blood pressure? I don't, but I do feel somewhat more relaxed when I eat sea veggies which are full of electrolyte minerals, such as calcium, magnesium, sodium, and potassium.

 

[Jonathan Edwards]

Do all people with OI have low blood pressure? I don't, but I do feel somewhat more relaxed when I eat sea veggies which are full of electrolyte minerals, such as calcium, magnesium, sodium, and potassium.

PoTS is supposedly OI without low blood pressure.

Other electrolytes like calcium, magnesium and potassium (sodium is salt) are not going to have any relevance to the effect of salt. Potassium is mostly inside cells, not in blood plasma. I rather doubt sea veggies are different from bananas in these ions! They are mostly known for continuing iodine.

 

[Mij]

Could be that my diet is lacking in iodine considering I add sea salt to foods for the last 25yrs which doesn't contain iodine like regular salt.

 

[JemPD]

The field of CFS research and medicine is significantly underfunded and neglected, with psychosomatic medicine taking the forefront. I am uncertain if the same issues are present in Autonomics research and medicine, but there should be a higher standard for the scientific basis of medical advice given to patients.

I cannot definitively state that salt intake increases blood volume. I am emphasising that if some of the current medical advice provided by prominent figures in the field is poorly supported by evidence, it is important to gain a better understanding of the reasons behind this.

agreed