Reduced weight gain and adiposity in C57BL/6 mice provided anthocyanin‐rich purple corn extract is dependent on the composition of the high fat diet

Reduced weight and fat gains in mice provided high fat diets (HFD) supplemented with anthocyanin (ACN)‐rich extracts, including purple corn extract (PCE), have not been consistently demonstrated. We tested the hypothesis that the effect of PCE on diet‐induced obesity in C57BL/6 mice was dependent on the composition of the background HFD. Two background HFD, each containing 58% of energy as fat, were compared. The Surwit diet was composed of hydrogenated coconut oil as the primary fat source and a 50:50 mixture of maltodextrin 10 and sucrose as the carbohydrate source. The Tsuda diet was composed of lard as the primary fat source and sucrose as the exclusive carbohydrate source. Each background HFD was prepared with and without 5% PCE (PCE ACN content = 4%). Mice were fed each diet (9 mice/diet) for 12 weeks. The addition of PCE to the Tsuda diet significantly (P<0.05) reduced weight gain, fat mass gain, and percent body fat. In contrast, the addition of PCE to the Surwit background diet had no affect on weight gain and tended to increase both percent body fat and fat mass. Insulin levels were higher on the Tsuda diet relative to the Surwit diet. PCE addition to the Tsuda diet, but not the Surwit diet, significantly decreased insulin levels. These data demonstrate that the effect of PCE on diet‐induced obesity and insulin resistance is strongly dependent on the choice of the background HFD. Support by NIH grant P50AT002776.