From:
Bruce Williams, DVM
Date: 2001-10-19 02:29:00 UTC
Subject: Re: Dr. Williams: Low protein diets and renal disease
--- In Ferret-Health-list@y..., meesh meesh <meeshmeesh1@y...> wrote:
> My question is somewhat academic (somewhat
> practical, and somehat personally relevant - re:
> Mighty Mouse, who has been on a high protein (baby
> food supplemented) diet for insulinoma - last BG was
> 96 :), and has one failing kidney), but I am
> academically curious as well. I know there is some
> "controversy" regarding low-protein diets and renal
> disease, albeit, I haven't researched the nature of
> the controversy. My question is coming from what I
> have learned here at OSU. I will be starting my
> GI/Urinary rotation next week, so this is coming from
> my 2nd year notes.
> What we learned is that while low protein diets can
> abate the signs of uremia, they do nothing to
> affect/slow the progression of renal disease. That
> being said, phosphorus itself *is* nephrotoxic, *and*
> it is usually found in high concentrations in high
> protein diets. Therefore, indirectly, low protein
> diets would be beneficial in that they restrict
> phosphorus intake.
Dear Michaela:
Let us progress from the fact that normal levels of phosphorus in the
normal kidney are not damaging (or we'd all die a lot sooner).
Evolution has chosen a level of dietary phosphorus that we can
handle, and has adapted our kidneys to adjust.
Research in rats has shown that even doubling and in some cases,even
quadrupling the level of dietary phosphorus in rats with normal
kidneys will not cause any damage. However, if you remove a kidney
(approximately 50% of the renal function) or more (this is how
researchers, damage to the remaining kidney will be seen. (The end
result of this toxicity is the deposition of calcium phoshorus salts
in the kidney and death of affected segments.)
The levels of phosphorus in high-protein diets are still not high
enough to cause a problem in the normal animal, so these diets, or
those with less phosphorus really will have little effect on a ferret
whose is not in renal failure. However, the animal in renal failure,
who has less than 50% of functioning kidney left (actually probably
less than 66% - which is when we get our first inklings of renal
damage in domestic species) is more prone to damage from high levels
of dietary phosphorus.
Hope that helps.
With kindest regards,
Bruce Williams, DVM