4 ms·
Two things. 1. It's possible that we've reversed the causal association for all these years. You don't always get expansion of the extracellular fluid space wi
by carbocation 15y ago
Two things.
1. It's possible that we've reversed the causal association for all these years. You don't always get expansion of the extracellular fluid space with chronic kidney disease due to hypertension; with some tubulointerstitial diseases, you develop salt-wasting nephropathies. Perhaps these were the hypertensive patients who were referenced in the article, voraciously eating salt due to a deficiency caused by their kidney disease? I'd like to see more data before being willing to overturn dogma, but it's not the most outlandish idea I've heard all day. Still, the authors' conclusions are most likely wrong.
2. There's a group at MGH doing a randomized clinical trial in which they are administering intravenous salt and measuring near-term blood pressure response. It's a one-off exposure, but it will be interesting to better nail down the relationship between serum sodium content and blood pressure via experiment rather than epidemiology.
- jonnathanson 15y ago"It's possible that we've reversed the causal association for all these years." This is intriguing, because a similarly reversed causality was prevalent in the diagnosis and management of kidney stones for many years. Perhaps this is TMI, but as a chronic kidney stone sufferer, I was told initially that I get too much calcium in my diet -- which builds up to cause the stones. Eventually, the doctors came around to the idea that I was actually secreting too much calcium into my bloodstream, and that secretion and consumption are not the same thing. In fact, I am losing more calcium than I consume, and I am losing much more than I should. Basically, I am deficient in calcium, even though my serum calcium levels are through the roof. (This phenomenon has underlying causes above and beyond the kidney disease; in fact, the kidney disease is most likely a secondary effect).
- Mz 15y agoThere's probably some things you can do about that in terms of dietary changes and supplementing other minerals/nutrients to help your body better deal with calcium. As a guess, you are probably also too acid (the body dumps calcium from the bones to mediate the blood PH, so what you describe can be due to high acidity). I have a condition which is essentially a salt-wasting condition and I found that getting enough salt wasn't enough. I had to get enough salt along with certain other things to properly absorb it. That approach reversed a lot of my symptoms (which are supposed to be irreversible). I've also worked a lot on kidney health. But don't have time to elaborate at the moment as I have to get ready for work.
- cperciva 15y agoIt's possible that we've reversed the causal association for all these years. Another possibility: Cortisol. People under chronic stress produce more cortisol, and high cortisol levels act to inhibit urinary sodium loss. Maybe the people having heart attacks aren't eating more sodium; they're just retaining it better as a side effect of the stress which is killing them.
- dlikhten 15y agoThe problem of correlation vs causality.
- jonnathanson 15y agoStress, cortisol, and let's not forget sleep deprivation -- also typically associated with the same lifestyle, also highly deleterious to health, and also correlated with heart disease.
- cperciva 15y agoRight, my point was that cortisol is the link between "lifestyle which results in early death" and elevated serum sodium.
- jonnathanson 15y agoUnderstood your point; was just adding to it. Sorry for the confusion.