I’ve been unable to find any scientific evidence for this but lots of anecdote when doing some research on electrolytes.
People on low carb/keto/ carnivore require more sodium because less carbs in the cell means less water (and I assume they mean increased extracellular fluid + lower blood sodium?) however the explanations don’t go beyond this.
I have seen data on fasting for week using only water leading to mild hyponatremia and I have clients who want to do low carb/keto say they “feel” better when they have more salt or electrolytes, I cannot rule out placebo here, but I let them at it.
With that said, even IF (and big IF) those on lower carbs had lower blood sodium concentrations, would this not balance out given we have data on tribes such as the Yanomami who consume less than 800mg/day.
Hey Adam,
I’m not sure what the exact question is here for a few reasons, e.g. low carb and keto are not synonymous as you know, short-term vs long-term sodium and fluid balance, and so on.
Conceptually, I think it’s helpful to keep in mind that perturbations in intake (e.g. fasting), carbohydrates, sodium, and/or fluid are all likely to have significant short-term effects on fluid and electrolyte status. Whether or not these effects are clinically significant depends on the severity and duration of perturbation, along with the individual of course.
Long-term, definitively no, individuals consuming a ketogenic or low-carb diets do not require more sodium for health purposes. Very active, lean, normotensive individuals may benefit from higher sodium intakes regardless of dietary pattern, though more people are likely to be harmed than helped by increasing sodium intake.
-Jordan
Thanks for the reply.
I used keto/low-carb together as I assumed if there was much impact on blood sodium concentrations for whatever reason both would be similar.
Fasting aside, if someone was transitioning and then maintaining a keto diet would you see any need for purposefully increases and or monitoring of their sodium intake for a period?
Electrolyte supplements seem to be very popular with low carb and keto dieters, they have their reasons, but I wanted to understand was there any actual physiological changes that would warrant this, other than placebo.
Related question, is there a lower limit to sodium consumption, or does the body just conserve more? No real strong info on this other than previously mentioned tribes who observationally consume a very small amount (naturally occuring I would assume).
Neither really have lasting effects on blood sodium per se’, but due to short term effects on fluid status via insulin (independent of an additional reduction in energy) can reduce blood pressure for a spell.
I do not think the vast majority of people (with nearly any dietary pattern) need to increase their sodium intake or supplement with electrolytes. I described the active individuals above who might.
No real lower limit to sodium intake , though very low intakes are mostly related to energy deficits. The body is exquisitely good at maintaining normal sodium and volume levels.