The Association Between Fecal Short-Chain Fatty Acids, Gut Microbiota, and Visceral Fat in Monozygotic Twin Pairs

Purpose: To examine the association of short-chain fatty acids (SCFAs), gut microbiota and obesity in individual twins and to control for genetic and shared environmental effects by studying monozygotic intrapair differences. Patients and Methods: The study recruited 20 pairs of monozygotic twins. Body composition measurements were performed by using the multi-frequency bioelectrical impedance technique. SCFAs were extracted from feces and quantified by gas chromatography mass spectrometer. Gut microbiota was evaluated by 16S rRNA gene sequencing. Results: Fecal SCFAs were negatively correlated with adiposity parameters including body mass index, visceral adipose tissue and waist circumference (all P < 0.05). Metastat analysis showed that the top 5 relatively abundant bacterial taxa of viscerally obese and non-obese groups were Bacteroides, Collinsella, Eubacterium rectale group, Lachnoclostridium, and Tyzzerella. Participants with visceral obesity had lower abundance of Bacteroides and Collinsella compared to non-obese patients (P < 0.05). Among them, the abundance of Collinsella was positively correlated with acetic acid concentrations (r = 0.63, P = 0.011). There were no significant intrapair differences in each SCFA concentrations between the twins in our study (P > 0.05). Conclusion: Low fecal concentrations of SCFAs were associated with visceral obesity, and the gut microbiota might be involved in the underlying mechanism.