title: Improved glucose tolerance with lifetime diet restriction favorably affects disease and survival in dogs.
abstract: Labrador retrievers (42 of original 48) were used to assess the effects of lifetime diet restriction on glucose tolerance at ages 9-12 y. Restricted-fed (RF) dogs were fed 75% of the same diet consumed by control-fed (CF) pair-mates. An intravenous glucose tolerance test was done annually (maximal stimulation, nonsteady-state). Diet treatment, age, and interactions were fixed effects. Statistical procedures used included mixed-model, repeated-measures ANOVA; least-squares means; Tukey's multiple comparison; paired t tests; and Spearman rank correlations. Glucose k-value and half-life, and insulin sensitivity (total, and 9, 10, 11 y, and per lean mass) were higher (P < 0.05) in RF than in CF dogs. Late-phase insulin release [area under the curve (AUC) 30-120 min] was less (P < 0.05) in RF than in CR dogs. Early-phase insulin release (AUC 0-5 min), y 12 insulin sensitivity and insulinogenic index did not differ between RF and CF dogs. Insulin peak, delta and total AUC increased (P < 0.05) with age, whereas the glucose k-value and glucose half-life were not affected by age. Insulin sensitivity was negatively, and insulin AUC 30-120 min, peak and delta glucose were positively correlated with body weight, body condition score, fat mass, percentage of fat and abdominal fat/total tissue. Higher insulinogenic indices tended (P = 0.053) to be associated with greater median survival and dogs with higher insulin sensitivity were at lower (P < 0.05) risk of dying or receiving chronic disease treatment. Time to first osteoarthritis treatment or death was greater with lower basal glucose and higher insulin sensitivity (P < 0.05), but diet restriction explained most of this relationship's variation. Glucose disposal efficiency and insulin response were associated with increased quality and length of life in diet-restricted dogs.
authors.affiliation: Nestlé Purina PetCare Research, St Louis, MO 63164, USA. Brian.Larson@rdmo.nestle.com
authors.forename: Brian T
authors.initials: BT
authors.lastname: Larson
authors.forename: Dennis F
authors.initials: DF
authors.lastname: Lawler
authors.forename: Edward L
authors.initials: EL
authors.lastname: Spitznagel
authors.forename: Richard D
authors.initials: RD
authors.lastname: Kealy
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002908:Chronic Disease; D004032:Diet; D004285:Dogs; D005508:Food Deprivation / Q000502:physiology*; D005947:Glucose / Q000502:physiology*; D005951:Glucose Tolerance Test; D007328:Insulin / Q000097:blood / Q000502:physiology; D009026:Mortality; D010003:Osteoarthritis / Q000628:therapy; D016016:Proportional Hazards Models; D016019:Survival Analysis
chemical_list: D001786:Blood Glucose; D007328:Insulin; D005947:Glucose