Overweight and underweight status are linked to specific gut microbiota and intestinal tricarboxylic acid cycle intermediates.

BACKGROUND & AIMS: Intestinal short-chain fatty acids have been demonstrated to modulate host energy metabolism and are elevated in overweight and obese individuals. We hypothesized that other intestinal energy products especially tricarboxylic acid (TCA) cycle intermediates might also related to overweight status. In addition, little information is available regarding to the potential relationship between gut microbiota and underweight status. Therefore, the aim of this study was to investigate whether gut microbiota and intestinal energy metabolites differ in underweight, normal weight, and overweight individuals, and their correlations with host cardiometabolic risk factors.

SUBJECTS/METHODS: Gut microbiome, intestinal energy metabolites, circulating cardiometabolic risk factors, and proinflammatory markers were determined in 29 underweight, 67 normal weight, and 67 overweight adults.

RESULTS

The fecal concentrations of succinic acid, fumaric acid, malic acid, propionic acid, and adipic acid were significantly increased in the overweight individuals in parallel with a higher relative abundance of Veillonellacea after adjusting for multiple comparisons (all p < 0.05). The intestinal concentration of TCA cycle intermediate succinic acid was positively associated with body weight (r = 0.28, p = 0.04), and malic acid were in positive association with circulating total cholesterol, low-density lipoprotein cholesterol, and interleukin-1β (all r > 0.25, p < 0.05). Compared with the normal weight individuals, the gut microbial α-diversity was lower in the overweight (p = 0.007 for Shannon index and p = 0.009 for Ace index) and underweight (p = 0.05 for Shannon index and p = 0.08 for Ace index) groups. However, no significant differences in the overall gut microbiota composition were observed among the three groups.

CONCLUSIONS

Our findings revealed that low gut microbiota diversity was associated with both overweight and underweight status. Intestinal TCA cycle intermediates were associated with overweight development and might be potential markers for future studies related to gut microbiota and host cardiometabolic health.