Sammanfattning
Introduction: It is often claimed by laypeople that obese individuals and those around them suffer from more malodorous flatulence than do normal-weight individuals. This has not been scientifically substantiated. Materials and methods: Seventy-four obese and 39 normal-weight non-smoking subjects of both genders participated in the study. Twenty-four-hour production of the malodorous gas methane and the neutral gas hydrogen was measured on a standardised diet and physical activity programme with whole-body calorimeters. Results: Methane production (mL/day) in obese subjects was only 50% of that in normal-weight subjects (p< 0.05). There was no difference in hydrogen production. Obese subjects had a 26& higher 24-hour energy expenditure and a correspondingly higher energy intake than did normal-weight subjects (p< 0.0001). After adjustment for differences in energy intake the methane production in obese subjects was still markedly lower than in normal weight subjects. There was an inverse correlation between body mass index and methane production in both genders (p = -0.212, p = 0.068). Repeated measurements in the same individuals showed that gas production was a highly reproducible trait, with a personal diurnal profile. Discussion: The study refutes the hypothesis that obese subjects produce more malodorous flatulence than do normal-weight subjects and shows that obese subjects actually produce only half as much methane. The diurnal flatulence profile was found to be a personal trait with a high degree of reproducibility. This study is expected to be of use in the diagnosis of malodorous flatulence.