Effects of postexercise whole grain cereal supplementation on blood biomarkers and skeletal muscle GLUT4 gene expression

The purpose of this study was to determine the effect of postexercise whole grain cereal supplementation on blood biomarkers and skeletal muscle GLUT4 (glucose transporter subtype 4) gene expression. Eight untrained subjects (aged 20.7±3.1 years; body-mass index (BMI) of 23.28 ±1.65 kg/m 2; peak oxygen consumption of 47.3±2.9 mL/kg/min) participated in two separate trials which included fasting and supplementation of whole grain cereal after cycling at 70%-75% VO2 peak oxygen consumption for 60 mins. Muscle samples for GLUT4 mRNA were taken immediately and 3 hours after the exercise for GLUT4 mRNA analysis. Blood samples were obtained immediately after the exercise and every 30 minutes during 3 hours recovery for glucose, insulin, lactate and free fatty acid assays. GLUT4 gene expression was reduced when the whole grain cereal was given immediately following the exercise. Blood glucose and serum insulin concentrations were significantly hi gher in the whole grain cereal trial than those in the fasting trial. In contrast. Plasma lactate and serum free fatty acid concentrations were significantly lower in the whole grain cereal trial than those in the fasting trial. Our findings suggest that ingestion of whole grain cereal during postexercise recovery may (1) enhance the clearance of blood lactate; (2) elevate the levels of blood glucose and serum insulin; (3) down regulate GLUT4 gene expression in exercised human skeletal muscle.