Energy metabolism and substrate oxidation in patients with Crohn's disease

Weight loss and malnutrition are common features in patients with Crohn's d isease. This study was designed to evaluate diet-induced thermogenesis and substrate oxidation in patients with Crohn's disease. Twenty-three patients (17 women, 6 men; age 34 +/- 2 y) and 17 healthy control subjects (13 wome n, 4 men; age 36 +/- 3 y) were studied. Resting energy expenditure and fast ing substrate oxidation were measured by indirect calorimetry in the mornin g after an overnight fast. After a standard homogenized test meal (10 kcal/ kg), indirect calorimetry was performed every 30 min for 3 h to measure the diet-induced thermogenesis and the postprandial substrate oxidation. In th e fasting state, resting energy expenditure was significantly higher in pat ients than in control subjects (1433 +/- 43 versus 1279 +/- 53 kcal/24 h), Lipid oxidation was higher in patients with Crohn's disease than in control subjects (1.17 +/- 0.07 versus 0.61 +/- 0.11 mg . kg(-1). min(-1), P < 0.0 1). Postprandially, diet-induced thermogenesis was significantly lower in p atients with Crohn's disease than in control subjects (4.6% +/- 0.5 versus 6.3% +/- 0.5 of energy intake, P < 0.01). Lipid oxidation was significantly higher in-patients with Crohn's disease than in control subjects (0.78 +/- 0.05 versus 0.56 +/- 0.08 mg . kg(-1). min(-1), P < 0.05), and glucose oxi dation was lower in patients with Crohn's disease than in control subjects; In patients with Crohn's disease, lipid oxidation positively correlates wi th the disease activity evaluated by the Crohn's Disease Activity Index (r = 0.48, P = 0.02) but not with the use of corticosteroids or the nutritiona l state. In patients with active Crohn's disease (Crohn's Disease Activity Index >150), fasting and postprandial lipid oxidation was significantly hig her than in patients with inactive Crohn's disease (P < 0.05). In conclusio n, patients with Crohn's disease have increased fat oxidation, which correl ates with disease activity and this may explain the reduced fat stores in p atients with Crohn's disease. (C) Elsevier Science Inc. 2000.