为探索补充维生素D（VD）对于NAFLD患者肠道菌群的影响。本研究共纳入29例NAFLD患者，采用随机分组法分为对照组（只接受内科治疗，n=15）和VD组（在内科治疗的基础上，补充维生素D₂，n=14）。根据中国药典的剂量标准，对VD组NAFLD患者一次性给予60万国际单位VD₂，肌肉注射。30天后测定患者血清生化指标，采集患者粪便，进行16S rRNA测序分析，比较治疗前后肠道菌群在多样性、丰度的变化，以及肠道菌群与生化指标的相关性。研究结果表明：补充VD之后，NAFLD患者血清丙氨酸氨基转移酶（ALT）水平显著降低（P<0.001），肠道菌群多样性无显著变化（P>0.05），但毛螺菌科丰度显著降低（P<0.01），丹毒丝菌科（P<0.01）、丹毒丝菌科未命名属（P<0.05）丰度显著升高；毛螺菌科相对丰度水平与血清甘油三酯（TG）（P<0.05）呈显著正相关，丹毒丝菌科（P<0.01）和丹毒丝菌科未命名属（P<0.05）与血清25（OH）D水平呈显著正相关，而与ALT、天门冬氨酸氨基转移酶（AST）呈显著负相关（ALT：P<0.000 1；AST：P<0.05）；补充VD能够显著降低血清ALT水平，对NAFLD患者肝损伤有一定改善作用；VD能显著降低患者肠道菌群毛螺菌科的丰度，显著提高丹毒丝菌科和丹毒丝菌科未命名属的丰度，进而降低血清TG、ALT和AST水平。

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 600 000 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<0.000 1, 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.}