AIMS/HYPOTHESIS: Our aim was to test the hypothesis that TNF-alpha protein levels in skeletal muscle are important in mediating the improvements in glucose homeostasis that are associated with diet and exercise regimens intended to reduce cardiovascular risk. METHODS: We recruited 20 people with a body mass index of 32.1 +/- 1.2 kg/m2 (mean +/- SEM) and one other component of the metabolic syndrome. The average age was 51.2 +/- 8.1 years (mean +/- SD). Of the 20 subjects, 6 were men and 14 were women. All subjects completed an 8-week control period, followed by randomisation to 8 weeks of moderate cycling exercise (30 min, three times per week) or to a diet with the following characteristics: low in saturated fat, high in fibre, low glycaemic index, rich in complex carbohydrates. RESULTS: Diet induced a small reduction in body mass index (3.0 +/- 0.7%, p<0.05), although weight loss was not intended. Exercise training increased maximum oxygen consumption by 12 +/- 6% (p<0.05). Both interventions reduced fasting plasma insulin levels by about 20%. Diet reduced skeletal muscle TNF-alpha protein by 54 +/- 10% (p<0.05), an effect that was independent (p=0.94 in covariate analysis) of the small concurrent weight loss (-2.8 +/- 0.7 kg). Levels of GLUT4 protein were unchanged in the diet group. In contrast, exercise training did not significantly change TNF-alpha protein expression, but GLUT4 protein expression increased by 105 +/- 37% (p<0.05). CONCLUSIONS/ INTERPRETATION: These data indicate that the metabolic benefits of a diet aimed at cardiovascular risk reduction are associated with a decrease in skeletal muscle TNF-alpha protein.
RCT Entities:
AIMS/HYPOTHESIS: Our aim was to test the hypothesis that TNF-alpha protein levels in skeletal muscle are important in mediating the improvements in glucose homeostasis that are associated with diet and exercise regimens intended to reduce cardiovascular risk. METHODS: We recruited 20 people with a body mass index of 32.1 +/- 1.2 kg/m2 (mean +/- SEM) and one other component of the metabolic syndrome. The average age was 51.2 +/- 8.1 years (mean +/- SD). Of the 20 subjects, 6 were men and 14 were women. All subjects completed an 8-week control period, followed by randomisation to 8 weeks of moderate cycling exercise (30 min, three times per week) or to a diet with the following characteristics: low in saturated fat, high in fibre, low glycaemic index, rich in complex carbohydrates. RESULTS: Diet induced a small reduction in body mass index (3.0 +/- 0.7%, p<0.05), although weight loss was not intended. Exercise training increased maximum oxygen consumption by 12 +/- 6% (p<0.05). Both interventions reduced fasting plasma insulin levels by about 20%. Diet reduced skeletal muscle TNF-alpha protein by 54 +/- 10% (p<0.05), an effect that was independent (p=0.94 in covariate analysis) of the small concurrent weight loss (-2.8 +/- 0.7 kg). Levels of GLUT4 protein were unchanged in the diet group. In contrast, exercise training did not significantly change TNF-alpha protein expression, but GLUT4 protein expression increased by 105 +/- 37% (p<0.05). CONCLUSIONS/ INTERPRETATION: These data indicate that the metabolic benefits of a diet aimed at cardiovascular risk reduction are associated with a decrease in skeletal muscle TNF-alpha protein.
Authors: D A McCarron; S Oparil; A Chait; R B Haynes; P Kris-Etherton; J S Stern; L M Resnick; S Clark; C D Morris; D C Hatton; J A Metz; M McMahon; S Holcomb; G W Snyder; F X Pi-Sunyer Journal: Arch Intern Med Date: 1997-01-27