In aged dogs, polyphenol ingestion (including grape pomace), and vitamin use, are both thought to ameliorate the effects of aging on learning ability similarly beneficial effects have been reported for humans. We aim to complete a novel study into the efficacy of mixed extracts of grape and blueberry in counteracting age-related deterioration of function. This work comprises part of a project dedicated to the study of age-related cognitive decline in humans and dogs (the Neurophenols Consortium). Ratios of urinary biomarkers to Creat were calculated, and compared with acceptable maximal values obtained for healthy dogs, as reported in the literature. Biomarkers for early renal damage were also evaluated in plasma (cystatin C (CysC), and neutrophil gelatinase-associated lipocalin (NGAL)), and urine (CysC, clusterin (Clu), and NGAL). Routine markers of renal and liver damage, including creatinine (Creat), blood urea nitrogen, albumin, minerals, alkaline phosphatase (ALP), and alanine transaminase (ALT) were measured. Blood and urine samples were taken the week prior to study commencement, then at the end of the 24-wk study period. These groups received capsules containing no PEGB (control), or PEGB at 4, 20, or 40 mg/kg BW/d, for 24 weeks. Safety was evaluated using four groups of 6 dogs.

Polyphenol expression was analyzed by UHPLC-MS/MS over 8 hours, for dogs given PEGB at 4 mg/kg. Our aim was therefore to evaluate the renal and hepatic safety, and measure plasma derivatives of a polyphenol-rich extract from grape and blueberry (PEGB from the Neurophenols Consortium) in dogs. The European Pet Food Industry Federation (2013) considers only the grape or raisin itself to be potentially dangerous grape-seed extracts per-se, are not considered to be a threat. Of concern to us were cases of acute renal failure in dogs, after their ingestion of grapes or raisins. However, beneficial effects achieved by mixing grape and blueberry extracts have yet to be evaluated in dogs, or their bioavailability assessed.

Grape and blueberry extracts are known to protect against age-related cognitive decline.

Grapefruit seed extract for dogs