Every hyponatremia consult recommends increasing protein intake to increase the solute load and increase urine output. But how much protein do you need to move the needle?

Here is another way to do the calculation

Protein is about 16% nitrogen

And urea is just under 50% nitrogen by weight

So if you are using 2 packets of urea (30 grams) a day for SIADH, you should get an equivalent amount of urinary solute (and increased urine output) with three scoops of protein powder.

For this calculation I used this protein powder which has 18 scoops for $22.

Published literature

The TREASURE Study (H/T Pablo Garcia) tested 17 patients with SIADH. They were given 90 grams of protein (three scoops!) for seven days then after a washout they were given 30 grams of urea. for seven days

The results were modest, but there was little material difference between the two therapies.

Patients quality of life improved during the protein phase and fell during the urea phase

The rating for overall well-being slightly improved from 7 VAS points (6-8) to 8 VAS points (7-8) (P = .24) upon protein intake, whereas it slightly worsened from 7 VAS points (6-7) to 6 VAS points (6-7) (P = .40) upon urea intake.

Update

David Goldfarb asked about changes in bicarb with the protein supplement

So I went digging into the supplement to see if they reported it. (They did not) and I came across this humdinger

It shows patient level data on the change in Na. Strange that they didn’t mention that almost a third of patients in the in protein supplement group had their sodium fail. No failures among the urea patients (except one person with inadequate protein intake. That is the asterisk).

Animated gif to make this more clear

I’m glad this is reported. But it should not be in the supplement, it should be in the main paper.

Hot Dog Therapy

In a related note, Roger Rodby suggests hot dog therapy.

I took Roger’s hotdog therapy and made it into an animated gif

Here are the two key slides in the build

and