After mom handed me a print-out about vets treating ESRD animals' phosphorus with chitosan, I had to do some more research. The below article was the first I came across and I thought it was very interesting so I dug deeper.
Effect of Chitosan on renal function in patients with chronic renal failureThere is a chitosan gum called
RenaGum, specifically for dialysis patients. I noticed someone had posted about it a couple years ago but never followed up. There are only a few published studies out there about the gum, but they seem to pre-date this product.
I'd heard about chitosan before and the benefits, but had no idea it was so broadly used and even in conventional medicine. Even more surprising was that
WebMD didn't seem to have any bias against it as a non-pharmaceutical.
Also, here is a link to info on the pet version of chitosan under the brand name:
Epakitin.