Medium-chain triglycerides reduce diarrhea with improved immune status and gut microbiomics in tunnel workers in China.

Adverse environmental factors in tunnels increase the occurrence of respiratory and intestinal inflammatory disease, which is seriously harmful to worker health. It is reported that medium-chain triglycerides (MCT) can improve immune status and alter the gut microflora. This study investigates MCT effects on immune status and gut microbiota among tunnel workers.Forty-five workers were randomly divided into an MCT group (n=30) and control group (n=15), where they ingested MCT-milk or a placebo milk for 12 weeks, respectively. The primary outcome measure was the incidence of respiratory infection and diarrhea. Secondary outcomes were changes in serum immune-related markers and changes in gut microbiota.The incidence of diarrhea in MCT group was significantly decreased after 4 weeks (p<0.01), with no significant differences in the control group. MCT reduced the level of pro-inflammatory cytokines (TNF-α, CRP, and IL-6) and enhanced the anti-inflammatory cytokines (IL-10, C3, C4, IgA, IgG, and IgM), respectively (p<0.01). The Chao index was reduced (p<0.01) and microbiota composition changed significantly after 12 weeks of MCT intervention. MCT reduced the abundance of Bacteroides, Roseburia, Ruminococcus_1, Lachnospira and increased that of Blautia and Fusicatenibacter at the genus level (p<0.01).The consumption of MCT reduces diarrhea occurrence and improves serum immune profiles together with gut microbiomics in tunnel workers.