Capsaicin in diet does not affect glycogen contents in the liver and skeletal muscle of rats before and after exercise.

Effects of capsaicin, a pungent principle of hot red pepper, on glycogen contents in the liver and skeletal muscle at rest and during exercise were studied in rats. The contents of glycogen in the liver and soleus muscle, and the concentrations of serum glucose, lactate, free fatty acid and glycerol were examined. Capsaicin was supplemented at 0.014% of the experimental diet. Each group of rats was fed the capsaicin-diet ad libitum for 7 days, and then both groups of rats were fed isoenergetic diets with or without capsaicin for 7 days. Rats were trained running with a treadmill for 14 days. At the final stage of the experiments, 1 h running was loaded after the capsaicin diet or the control diet. The glycogen contents in the liver and soleus muscle were not significantly different between the capsaicin-diet group and the control-diet group after the meal and during exercise. The concentrations of serum glucose, lactate, free fatty acid and glycerol were not significantly different between the two dietary groups after the meal and during exercise. The results in this study suggest that the intake of capsaicin have little effect on glycogen contents in the liver and soleus muscle at rest and during exercise in rats previously fed a capsaicin-diet ad libitum for 1 week.