blsm
#305
If you run across anything good please share and I’ll do the same of course.
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blsm
#306
I do wonder if getting labs drawn at different points in the salt cycle could make a difference in results even though blood levels are highly regulated? This has been discussed in the thread already but I tend to forget about the salt cycle they discovered.
“Salt cycle
It is a challenge to measure the long-term effects of salt because of difficulties in regulating dietary intake. However, Mars 500 “mission controllers” were able to dictate the amount of salt that the crew received each day.
During this mission, and a preliminary mission with a different crew that lasted 105 days, 12 crew members consumed either 6, 9 or 12 grams of salt per day for 29 to 60 days. Previous research suggests that there should be roughly the same amount of salt in urine as has been eaten that day.
Instead, the crew excreted different amounts each day, revealing a six to seven-day cycle of salt retention and excretion. The patterns varied between crew members, but were consistent within individuals. For example, on a 12-gram daily salt diet a crew member might excrete as little as 6 grams on day three of the cycle, and peak at 18 grams on day five.”
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A_User
#307
The problem isn’t only an acute blood pressure response even if in most people drastically lowering salt intake would decrease their blood pressure rather than cutting down slightly. It’s the possible long term impacts of excess salt intake that can’t be detected now except be explained as some disease, or aging, like possibly causing HBP that wouldn’t be affected much by cutting down on sodium intake later.
Sodium excretion isn’t a biomarker for health related to optimal sodium intake, it’s just an estimate of the amount of sodium you consume. Add potassium to that and it’s confounded by vegetable intake – isn’t it still just a marker of how much you consume of each?
In that there will be a system maintaining levels it would be expected to over correct and hence end up with a cycle.
I looked at the data on that a long time ago and was surprised to find that it was the chloride rather than the sodium that was mainly responsible for the increase in blood pressure on high salt diets. That’s why I take a little extra sodium to complement my failry low salt diet instead of adding extra table salt to it.
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My serum sodium level is currently running quite low (about 135/136) notwithstanding high sodium (citrate) supplementation. It is probably, however, an adjustment to a higher turnover.
If you have any links to the research pointing at chloride that would be helpful.
I wish I had the links. I thought I had the research saved on my computer but I can’t find it. 
[quote=“Olafurpall, post:309, topic:11257”]
chloride rather than the sodium that was mainly responsible for the increase in blood pressure on high salt diets.
[/quote]I think that there is evidence to support this. “Sodium chloride increased mean arterial blood pressure in the salt-sensitive subjects; sodium citrate did not.”
NEJM crossover in salt-sensitive hypertensive men (n=5): Adding NaCl for 7 days raised BP by ~16/8 mmHg; the same sodium as sodium citrate did not. Switching from NaCl to sodium citrate reversed the rise—despite similar sodium retention—implicating the anion.
Randomized crossover in hypertensives (n=6): NaCl loading increased BP; the same sodium as sodium phosphate did not; sodium retention was similar in both arms.
Hypertension trial stratified by salt sensitivity (n=40): In salt-sensitive subjects, NaCl increased mean arterial pressure, whereas sodium citrate did not; differences tracked with acid–base changes.
Crossover in mildly hypertensive & normotensive adults (n=20): NaHCO₃ (bicarbonate) tended to lower SBP (~5 mmHg in hypertensives) while equimolar NaCl did not lower BP—again pointing to an anion effect.
Elderly normotensives, double-blind crossover (n=21): A NaHCO₃-rich mineral water period had lower mean arterial BP than baseline, while a NaCl-rich water period abolished the BP reduction achieved by prior salt restriction (i.e., BP went back up toward baseline).
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Shady
#313
Interesting. How do you reconcile that with the fact that KCL generally shows benefit to BP and can be used as a salt replacement for Na sensitive individuals? I honestly haven’t looked into it. Always assume Na was the issue.
1 Like
tananth
#314
Most diets are deficient in Potassium, in which case any potassium supplementation, including KCl will reduce BP somewhat. However this study from 2005 showed that supplementing with Potassium Citrate (instead of KCl) lowered BP by slightly more : Potassium Citrate vs Potassium Chloride effect on BP
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People tend to think of Citrate as inert which is an error.
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