Differences in metabolic variables between adult coeliac patients at diagnosis and patients on a gluten-free diet

Background: Coeliac patients often have nutrient malabsorption with nutritional status impairment, but no report on their energy requirements is available. In this study body composition, dietary habits, basal energy expenditure, and substrate oxidation were investigated in patients with the classic form of coeliac disease. Methods: Sixteen untreated and 18 adult coeliac patients on a gluten-free diet participated in the study. Body composition was assessed by anthropometry and bioimpedance. Energy expenditure was measured by indirect calorimetry. A food diary over 7 days was collected. Results: Coeliac patients showed reduced body weight components but not a different fat-free mass percentage compared with age- and sex-matched healthy volunteers. Basal metabolic rate normalized by fat-free mass (BMR/FFM) was higher in coeliac patients than in controls. Untreated patients showed a significantly higher non-protein respiratory quotient with regard to both treated patients (P < 0.01) and controls (P < 0.05), an increased percentage of carbohydrate intake, and a good correlation between lipid faecal loss and carbohydrate oxidation (Spearman R = 0.74; P < 0.01). Conclusions: Both groups of patients had lower fat mass and FFM content than controls. The preferential carbohydrate oxidation in untreated patients might be a result of both lipid malabsorption and high carbohydrate intake.