Original Research Communications Diet-induced weight loss, exercise, and chronic inflammation in older, obese adults: a randomized controlled clinical trial1–3

Abstract

Background: Persistent, low-grade inflammation is an independent predictor of several chronic diseases and all-cause mortality. Objective: The intention of this study was to determine the inde-pendent and combined effects of diet-induced weight loss and ex-ercise on markers of chronic inflammation. Design: Three hundred sixteen community-dwelling, older ( 60 y), overweight or obese [body mass index (in kg/m2) 28], seden-tary men and women with radiographic evidence of knee osteoar-thritis were randomly assigned to four 18-mo treatments: healthy lifestyle control, diet-induced weight loss, exercise, and diet plus exercise. The exercise intervention consisted of combined weight training and walking for 1 h 3 times/wk. The weight-loss interven-tion consisted of a weekly session with a registered dietitian to provide education and support for lowering energy intake. Results: The diet-induced weight-loss intervention resulted in sig-nificantly greater reductions in concentrations of C-reactive protein (P 0.01), interleukin 6 (P 0.009), and soluble tumor necrosis factor receptor 1 (P 0.007) than did no weight-loss treatment. Changes in soluble tumor necrosis factor receptor 1 but not in C-reactive protein or interleukin 6 correlated with changes in body weight. Exercise training did not have a significant effect on these inflammatory biomarkers, and there was no significant interaction between weight loss and exercise training. Conclusions: These findings provide evidence from a randomized controlled trial that a dietary intervention designed to elicit weight loss reduces overall inflammation in older, obese persons. Addi-tional studies are needed to assess the effects of different modes and intensities of exercise on inflammation. Am J Clin Nutr 2004