The effect of dietary olive polyphenols on markers of inflammation and bodyweight in senior domestic cats

The high rates of obesity and degenerative joint disease in companion animals has resulted in a demand for dietary supplements that support joint health and reduce inflammation. Polyphenols have received considerable attention in this space, although literature in companion animals is lacking or conflicting. This study determined whether a diet supplemented with olive polyphenol extract had the potential to reduce inflammation and/or bodyweight. Eight senior domestic cats aged 11.01 ± 0.74 years (mean ± standard error of the mean) and weighing 3.6 ± 0.3 kg (mean ± SEM) were used for this study. The cats were fed, ad libitum with a complete (AAFCO) canned diet supplemented with 0.1% olive polyphenol extract for 56 days. Cats were weighed weekly and blood samples taken on day 0 (baseline), 28, and 56 of the study. Biochemistry, haematology, and cytokine (19 cytokines or chemokines) panels were run for each blood sample. While there was an initial aversion to the supplemented diet, intakes of the cats increased, and they consumed enough to meet or exceed their daily maintenance energy requirements by day 10 of the trial. On average, the cats lost approximately 8% of their starting weight over the trial, which was interesting given that feed intake exceeding maintenance energy requirements for most of the study. Whether the decrease in bodyweight was due to seasonal changes, the supplemented diet, or a combination of the two warrants further investigation. There were little to no changes to any of the blood parameters, which was surprising given that previous studies have reported reductions in pro-inflammatory cytokines following polyphenol supplementation. Perhaps a higher concentration of olive polyphenols is required to elicit the anti-inflammatory response observed in other species. A study evaluating the dose-dependent effects of dietary polyphenols on inflammatory and oxidative markers in cats would be valuable in this context.