Effects of Vitamin D Supplement on Gut Microbiota in Nonalcoholic Fatty Liver Disease Patients

To explore the effect of VD supplement on the gut microbiota of NAFLD patients, this paper carried out a controlled clinical research on 29 NAFLD patients who were randomly divided into control group (n =15) who received the standard care and internal medical treatment, and VD treatment group (n=14) who received the standard care and internal medical treatment plus high dose of VD₂ treatment. According to Chinese Pharmacopoeia, NAFLD patients were given 600000 IU VD₂ by intramuscular injection at once. At day 30, serum biochemistry indicators were determined, stool samples were collected, and the fecal microbiota was measured by 16S rRNA sequencing analysis. The diversity and abundance of microbiota before and after the VD₂ treatment were compared and the correlation between microbiota and biochemistry indicators was detected . The results show that after VD supplement, the serum alanine aminotransferase (ALT) of NAFLD patients is significantly decreased (P <0.001), and there is no significant change in the gut microbiota diversity. However, there is a significant decrease in family Lachnospiraceae (P<0.01), a significant increase in family Erysipelotrichaceae (P <0.01) and genus unidentified_Erysipelotrichaceae (P<0.05) after VD supplement; the relative abundance of family Lachnospiraceae was significantly positively correlated with serum triglycerides (TG) levels (P<0.05); the relative abundance of family Erysipelotrichaceae (P<0.01) and genus unidentified_Erysipelotrichaceae (P<0.05) were significantly positively correlated with 25(OH)D, negatively correlated with serum ALT, serum aspartate aminotransferase (AST) (ALT: P<0.0001, AST: P<0.05). In conclusion, VD supplement can reduce the serum ALT significantly, and alleviate the liver injury of NAFLD patients. VD can significantly reduce the abundance of Lachnospiraceae, significantly increase the abundance of Erysipelotrichaceae, unidentified_Erysipelotrichaceae, then decrease serum TG, serum ALT and serum AST.