Vitamin E supplementation fails to impact measures of oxidative stress or the anaemia of feline chronic kidney disease: a randomised, double‐blinded placebo control study

Abstract

This study was designed to test the hypothesis that supplementation with vitamin E, an antioxidant, in cats with chronic kidney disease (CKD), would reduce oxidative stress and its impact on RBC membrane fragility, resulting in these cats maintaining a greater packed cell volume (PCV) compared with CKD cats not receiving supplementation.Thirty‐six cats with CKD were randomly assigned to receive either daily vitamin E or a placebo for 3 months in a double‐blinded study design.History and physical examination, blood pressure, complete blood count (CBC), PCV, biochemical profile and urinalysis (UA) were determined. Parameters of oxidative stress and osmotic fragility were measured. Cats were administered vitamin E or placebo once daily for 3 months. Cats were then reassessed and the diagnostics were repeated.Twenty‐four cats completed the study, 11 in the vitamin E group and 13 in the placebo group. There were no significant differences between the two groups at the start, or upon completion of the study with regard to biochemical parameters, oxidative stress, erythrocyte osmotic fragility or PCV. None of these parameters changed significantly in either group over the treatment period.Daily supplementation with 30 IU of vitamin E did not affect the measures of oxidative stress or the anaemia seen in cats with CKD.

Supplementation of vitamin E as an addition to a commercial renal diet does not prolong survival of cats with chronic kidney disease

“…In a previous study in CKD cats, 30 IU of vitamin E daily per cat had no effect on measures of oxidative stress or anaemia [ 41 ]. The authors suggested that the vitamin E dose may have been too low to be effective, although the vitamin E was not measured in the study [ 41 ].…”

“…In a previous study in CKD cats, 30 IU of vitamin E daily per cat had no effect on measures of oxidative stress or anaemia [ 41 ]. The authors suggested that the vitamin E dose may have been too low to be effective, although the vitamin E was not measured in the study [ 41 ]. Since there was a statistically significant increase in plasma vitamin E concentration in our study, we can assume that the selected vitamin E dose was appropriate.…”

“…To the authors’ knowledge, there are currently no studies that would evaluate high dose vitamin E therapies for long time periods in cats. To the authors’ knowledge, only two studies [ 21 , 41 ] investigated vitamin E supplementation in CKD cats. In one study, a supplementation period lasted for 4 weeks [ 21 ] and in the other study, the supplementation period lasted for 3 months [ 41 ].…”

“…To the authors’ knowledge, only two studies [ 21 , 41 ] investigated vitamin E supplementation in CKD cats. In one study, a supplementation period lasted for 4 weeks [ 21 ] and in the other study, the supplementation period lasted for 3 months [ 41 ]. The cats in the present study already received a kidney diet that was supplemented with vitamin E, and there could be a risk of possible overdosing if the supplementation period was longer.…”

“…It is still unclear whether antioxidant treatment in cats with CKD has the same effect on clinical status and survival as in human patients [ 38 , 40 ]. In feline CKD patients, vitamin E supplementation was reported to have no effect on total antioxidant capacity, measured as copper ion reducing antioxidant capacity, or anaemia [ 41 ]. In another study, supplementation with a combination of antioxidants (vitamin C, vitamin E and β-carotene) resulted in a significant decrease in oxidative DNA damage [ 21 ].…”