Interpretive Summary: Glycemic response in Siberian Huskies fed single starch ingredients and commercial extruded dog foods with different carbohydrate sources
By Anne Zinn
A recent study published in the Journal of Animal Science adapted the established glycemic index (GI) methodology used in human research to perform two studies in adult, client-owned, non-racing Siberian Husky dogs in order to assess the blood glucose-raising potential of pulce-based dog foods. Grain-free pet foods have been popular for a number of years, despite the FDA’s 2018 warning of the potential link between grain-free dog food and the development of canine cardiomyopathy; as a result, the use of non-grain carbohydrate sources, such as peas, lentils, beans, and chickpeas, has been of interest to pet food manufacturers. The GI was originally created for human use to rank foods based on their acute postprandial glycemic response. Currently, pet food marketing claims concerning GI are ingredient based and communicate the inclusion of starch sources known to be low GI in humans, but these claims are not based on standardized GI testing in dogs and GI methodology has not been validated for use in companion animals. Therefore, the aim of the two-part study was to further develop GI methodology in dogs.
The first study aimed to determine the GI of single starch sources, such as white bread, cooked white rice, and cooked green lentils, using a glucose solution as the control. In the second study, the glycemic and insulinemic responses of four commercial extruded dog foods that contained different categories of starch sources (traditional grain, whole grain, grain-free, and vegan) were measured. It was hypothesized that the lowest and highest glycemic and insulinemic responses would result from the grain-free and traditional grain diets, respectively.
Overall, despite the notable popularity that grain-free dog food has had with consumers, the results of this study suggest that different starch sources in commercial extruded diets may not have significant effects on GI or postprandial glycemic and insulinemic response in dogs. At its conclusion, the GI methodology was not validated for use in canine species, and it is likely that the results of this study were due to higher interindividual variation or inadequate study power. The physiological relevance and the potential health benefits of low GI foods for dogs are still unknown, but based on these results, it does not appear that the dog foods containing different types of carbohydrate sources provide improved glucose and/or insulin control. Claims regarding the GI of pet foods cannot be substantiated due to the postprandial variability in glucose and insulin responses in dogs. More research is recommended to further improve and streamline canine GI testing before it can become a validated method for use in dogs, and this study will help to better define future studies.
The full paper will be available soon on the Journal of Animal Science website.