There is no published consensus and a scarcity of scientific literature on the proper diet for patients with significantly increased SDMA values within IRIS stage 1 CKD. Despite this, the authors believe consideration of nutrients of concern in the current diet and initiation of owner discussion regarding dietary changes should begin with recognition of this CKD stage.
A review of the current diet is prudent, particularly when patients are fed over-the-counter products, as these can be excessively high in nutrients relative to requirements for animals. This is typically done for palatability and marketing reasons. There are no Association of American Feed Control Officials (AAFCO)11 maximums on protein, sodium, or potassium in pet foods, and the allowed maximum on phosphorous is 5 times the National Research Council’s (NRC’s) adequate intake values.12
The authors suggest that if levels of nutrients of concern in the current diet are excessive—and because chronic renal disease is always progressive (and phosphrous intake appears directly related to the rate of CKD progression)—it is sensible and does not harm the patient to transition to a diet closer to AAFCO minimums. AAFCO minimums are lower limits on the food product and should not be mistaken for minimum animal requirements. It is important to recognize that a patient eating a diet consisting of nutrients of concern at or close to AAFCO lower limits will unlikely benefit from diet transition, further proving the need for assessment of the current diet.
For patients with IRIS stage 2 CKD, recommendation of a “kidney” or “kidney-friendly” diet may (or may not) be indicated or beneficial for the patient. This is because dietary descriptors such as renal, kidney, supportive, or protective are neither nutritionally nor officially defined terms. No nutrient profile is appropriate for all renal patients (or all IRIS stages), and each manufacturer decides independently on the nutrient profile of products intended and marketed for animals with CKD (Tables 1 & 2).