Acute and Chronic Effects of Low Versus High Glycemic Index Carbohydrate Sources on Metabolic and Cardiovascular Responses in Lean and Obese Dogs
In dogs, nutrition has been implicated in the development of numerous chronic diseases, including obesity, diabetes and cardiovascular disease. Health claims for dog food are not regulated in Canada, thus many claims do not have a scientific basis. The development of a pet food with proven health benefits is important to pet owners as well as the pet food industry. The purpose of this study was to develop a low glycemic canine diet that will provide health benefits for dogs, namely decreased serum insulin and glucose concentrations, reduced food intake and weight gain, and improved cardiovascular health. To achieve this objective, four studies were performed. These studies examined the acute and longer term health effects of feeding unprocessed as well as extruded carbohydrate sources as both single ingredients and in complete dog diets. In addition, metabolic and cardiovascular health parameters were measured in dogs when they were lean, obese and after weight loss. Post-prandial serum glucose and insulin responses were used to determine glycemic index of the carbohydrate sources and to evaluate glucose tolerance. Flow-mediated dilation, echocardiography and blood pressure were used to assess cardiovascular health. Computed tomography was performed to measure body fat amount and distribution. Leptin, adiponectin and C-reactive protein were also analyzed. The results of these studies found that peas had a lower glycemic index compared to barley and rice, but that after extrusion, the glycemic index of the pea diet was not different than the rice diet. Post-prandial hyperglycemia in dogs was associated with acute changes in endothelial function which may be related to increased methylglyoxal concentrations. However, several negative health effects were observed in dogs after only 12 weeks of obesity and weight loss reversed some, but not all, of these changes. The pea-based diet reduced post-prandial insulin response in obese dogs after 12 weeks on the diet even though no changes were observed in body fat amount or distribution. In conclusion, this research supports the usefulness of peas as an ingredient in canine diets and provides valuable data for the pet food and pulse industries, as well as for veterinarians and pet owners.
Dogs, Carbohydrates, Glycemic Index, Cardiovascular, Obesity
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