Effects of curcuminoid supplement on cardiac autonomic status in high-fat-induced obese rats

Sudden cardiac death in obesity is frequently associated with sympathetic activation due to an elevated plasma free-fatty acid (FFA) level. Curcuminoids, the phenolic yellowish pigments of turmeric, display antioxidative and lipid-lowering activities. We hypothesized that curcuminoids ameliorate cardiac sympathovagal disturbance in high-fat-induced obese rats.

Male Wistar rats were divided into five groups. A normal-diet control (NDC) group received a normal-fat diet (12% calories as fat) and a high-fat-diet control (HDC) group received a high-fat diet (60% calories as fat) for 12 wk. Three other groups received high-fat diets with curcuminoid supplement at concentrations of 30mg (HD(30)), 60mg (HD(60)), and 90mg (HD(90)) per kilogram of body weight every day for 12 wk. Heart rate variability was determined to assess cardiac autonomic status at weeks 0 and 12.

Body weight, visceral fat mass, plasma FFA, and glucose levels increased significantly in the HDC group compared with the NDC group. Low frequency power in normalized units (LFnu) and the ratio of LF to high-frequency power (HF) in the HDC group were significantly higher, whereas HFnu in the HDC group was significantly lower than in the NDC group. Plasma FFA levels correlated significantly with LFnu and LF/HF ratio. Compared with the HDC group, plasma FFA, glucose levels, LFnu, and LF/HF ratio were significantly decreased in the HF(30), HF(60), and HF(90) groups.

Elevated plasma FFA in high-fat-induced obese rats is associated with an increased LF/HF ratio, an expression of sympathovagal disturbance. Curcuminoid supplementation ameliorates cardiac autonomic imbalance in high-fat-fed rats, probably due to its lipid-lowering effect.