Potassium RDA and Sodium overconsumption


#1

I had a thought. Is it possible that the Potassium RDA has been artificially inflated to compensate for the fact that most people’s salt intake is too high? The theory here would be that Sodium and Potassium need to be balanced, and if you can’t stop people taking too much Sodium, maybe you can at least give them more Potassium to match.

I looked into it and apparently the recommendation is that you get at least twice as much P as S (currently searching for a proper source for this), and still higher ratios may be more favourable, at least if you follow Paleo-diet logic. In this light I have changed my spreadsheet to have my target intake of P tied directly to my recipe’s S content, rather than a fixed value. I thought this info may be helpful to those seeking optimum nutrition.


Optimal Micronutrient Ratios
#2

I’d thought of that, too.
The reasoning behind this being the sodium/potassium ion pump.

It works by creating an electrochemical gradient by transferring 3 sodium ions out of the cell and 2 potassium ions in.

It would make sense then that we need a 3/2 ratio of sodium to potassium to maintain balance.

The average American gets about 3400mg of sodium a day.

The recommendation based on this 3/2 ratio would then be 2266mg.

The average American consumes about 2350mg of potassium per day. It’s almost too convenient how well that matches up.

Italian researchers reported in a 2011 meta-analysis that a 1.64 g higher daily intake of potassium was associated with a 21% lower risk of stroke.

Adding this increase to our average results in 4000mg of potassium per day. Very close the the recommendation.

Based on that evidence, it’s your call and anybody’s guess.

The mechanism by which excessive salt can cause heart disease is independent of the sodium/potassium pump, however.

It lowers production of nitrous oxide in the body, a substance which "[inhibits] vascular smooth muscle contraction and growth, platelet aggregation, and leukocyte adhesion to the endothelium ".

So keeping the ratio correct but going over on your sodium would be a very bad idea.

It’s been suggested that 500mg of salt may be an adequate daily intake. I would do some research if you plan to eat outside of the bounds of the RDAs.


#3

I think that Potassium in excreted in urine in much higher amounts than Sodium, hence needing much more of it. LOTS of info here.


#4

A study in Italy found that very high levels of sodium were excreted in urine, and very little potassium.

Specifically look at the “excretion” rates.

Also, elements are only excreted when they are taken in excess or no longer needed. The excretion rate is dependent on dietary intake, not the other way around.


#5

Link?

See here and here and here and here.


#6

I have to post a link to prove the existence of the sodium/potassium pump and math? My last post contains a link, nothing else I’ve said is contested.


#7

It’s talking about the percentage excreted in urine in those links. By that it means, what is the main path that potassium takes when excreted from the body (sweat, poop, urine) not how much of the potassium taken is excreted. You’ve seriously misinterpreted this.

“The preponderance of dietary potassium (approximately 77 to 90 percent) is excreted in urine, while the remainder is excreted mainly in feces, with much smaller amounts being lost in sweat”

As in, out of all the potassium excreted, this is the percent lost from each route. Not out of all the potassium ingested.


#8

Sorry. For some reason I totally missed the link to the study in your post, that was what I was referring to.

The second link I posted contains info on absolute rates of excretion, what’s the problem?


#9

Sorry, I didn’t see that link. Only read the first so far.

The second link seems to suggest that not very much potassium is required relative to sodium intake, as you need to ingest very large quantities of sodium to increase the excretion (and therefore probably use) of potassium. But it’s difficult to interpret.

The third link implies that chloride causes the blood pressure-raising effects normally attributed to sodium. Again difficult to understand and interpret.

The table shown in the fourth link implies that a sodium intake less than or equal to 1.5g is adequate, since the excretion rate after 1.5g of intake increases faster than the intake.

(Suggesting the body is excreting more sodium disproportionately to the amount ingested, in an attempt to lower blood sodium concentrations)


#10

Isn’t the UK dri for sodium also much much lower than the US?


#11

The UK DRI is much higher.


#12

It was australia /new zealand , page 231

Adults
Men 460-920 mg/day (20-40 mmol)
Women 460-920 mg/day (20-40 mmol)
Rationale: As there are insuffi cient data from dose-response trials, an EAR could not be established,
and thus a RDI could not be derived. An AI for adults for sodium was set at 460–920 mg/day
(20–40 mmol/day) to ensure that basic requirements are met and to allow for adequate intakes of
other nutrients. This AI may not apply to highly active individuals, such as endurance athletes or those
undertaking highly physical work in hot conditions, who lose large amounts of sweat on a daily basis.


#13

I read something like 4000mg for England.
The UK = England when you live in the states. Forgot about those other countries lol.


#14

right? it was in the back of my mind as “one of the other countries where people speak english” , my original recipe I was getting an overdose of salts (forgot to carry a 1 or something) and i’d been meaning to actually do some digging onto who decided on these numbers, based on what studies and why.

It seems the terminology is international, EAR, DRI/AI/RDA , UL. Except you get these slight (or not so slight) variations, so whos standards of evidence am I supposed to go with?


#15

Good question. I would find out what the optimal serum sodium concentrations are and then do blood tests with different recipes. Barring that, I’m not sure there’s any way to really know.


#16

I am a bit late on this thread, it looks like, but regarding the 3/2 ratio near the top. Don’t forget that potassium weighs almost twice as much as sodium (39 vs 22), so you need more potassium than sodium to provide a 3 sodium ion : 2 potassium ion ratio.


#17

It was my understanding that the ratio was in terms of mass, not ions.


#18

If you want a 3/2 ratio to match that chemical reaction, then you’d want to use the moles not mass. If you’re dealing with chemical reactions, always use moles.

If we use @jeff_1089’s numbers, then you want a 13/11 (78/66) ratio of potassium to sodium by mass.

That sounds reasonable as an absolute minimum, I suppose. Although I personally feel more confident using the official USDA recommendations as hard limits.


#19

By the way, a high salt intake is unlikely to have any health effects as circulating levels are highly regulated.