Nutritional interventions that slow the age-associated decline in renal function in a canine geriatric model for elderly humans

Objective To determine the effects of feeding traditional and renal protective foods (RPF) supplemented with functional food bioactives on glomerular filtration rate (GFR), lean body percent (LB%), and selected circulating biomarker and metabolite concentrations in a geriatric dog model. Design Randomized block design and cross-sectional study. Setting: Hill’s Pet Nutrition, Inc. dog colony. Participants Eighty-one geriatric dogs (mean age, 10.4; range, 7.9-14.2 years) and 30 mature-adult dogs (mean age, 5.0; range, 3.3-6.9 years). Intervention Geriatric dogs were fed one of three foods (n = 27 per group) for 6 months: a traditional RPF (control) that was energy dense and mildly protein-restricted, or control food supplemented with increasing amounts of functional food bioactives: fish oil, lipoic acid, fruits and vegetables, and higher quality protein sources [functional foods one (FF1) and two (FF2)]. Geriatric dogs were compared before and after the feeding trial with mature adult dogs. Measurements Renal function was assessed by GFR, LB% was determined by dual energy x-ray absorptiometry, and circulating biomarkers and metabolites were measured in blood. Results Before the feeding trial, GFR (+28.2%), LB% (+18.6%), and serum total protein (+10.0%) were higher in mature versus healthy geriatric dogs (all P