Correlation between Vitamin D Status and Gut Microbiota in Patients with Inflammatory Bowel Disease

Objective To investigate the correlation between serum total 25-hydroxyvitamin D[T-25(OH)D]level and fecal microbiota in patients with inflammatory bowel disease(IBD). Methods Twenty-three patients with IBD completed the tests for serum T-25(OH)D,and the fecal microbiota was studied using V4 hypervariable region of 16S ribosomal RNA(rRNA)gene sequencing.According to serum T-25(OH)D level,the patients were divided into three groups including vitamin D normal group(n=5),vitamin D insufficiency group(n=5),and vitamin D deficiency group(n=13). Results There was no significant difference between these three groups in Alpha diversity or Beta diversity.Ternary pot at phylum level revealed that the abundance of Proteobacteria was the highest in the vitamin D deficiency group and Actinomycete was the highest in the vitamin D sufficiency group.Spearman correlation analysis showed that at the phylum level serum T-25(OH)D level was negatively correlated with the abundance of Proteobacteria(r=-0.445,P=0.033)and positively correlated with the abundance of Actinomycetes (r =0.447,P=0.033);at family level it was positively correlated with the abundance of Lachnospiraceae (r =0.414,P=0.049),Bifidobacteriaceae (r =0.468,P=0.024),Erysipelotrichacea (r =0.584,P=0.003),and Eggerthellaceae (r =0.507,P=0.014)and negatively correlated with the abundance of Aerococcaceae (r=-0.514, P=0.012);and at genus level it was positively correlated with the abundance of Blautia (r=0.459,P=0.028),Bifidobacterium (r=0.468,P=0.024),unidentified Erysipelotrichacea (r=0.485,P=0.019),Faecalitalea (r=0.544,P=0.007),Anaerostipes (r=0.475,P=0.022),Romboutsia (r=0.510,P=0.013),Flavonifractor (r=0.455,P=0.029),and Erysipelatoclostridium (r=0.617,P=0.002). Conclusions The fecal microbiota composition varies in IBD patients with different serum T-25(OH)D levels.The abundance of Proteobacteria increases and the abundance of Actinomyces decreases in IBD patients with vitamin D deficiency compared with IBD patients with normal vitamin D level.Serum T-25(OH)D level is negatively correlated with the abundance of some harmful bacteria(e.g.Proteobacteria)but is positively correlated with the abundance of some probiotics such as Lachnospiraceae,Bifidobacteriaceae,and Anaerostipes.