Anorexia nervosa (AN) is a lethal psychiatric disease with only narrow treatment possibilities. Recent study results point out, that gut microbiota might be a contributing factor in the development and persistence of AN through effects on the gut-brain-axis.

We used 16SRNA sequencing to characterize the composition and diversity of the gut microbiota of 18 AN patients, 19 normal weight controls and 19 athletes matched by age using stool samples. The QIIME-pipeline was used to assess the sequencing result. All participants completed an activity-questionnaire (IPAQ) and inventories to measure depression (BDI, HAMD).

Kruskal-Wallis test identified significant differences in alpha-diversity (Chao-1-estimator [P=0.013], number of observed species [P=0.027]) between groups. Spearman-Correlation revealed a significant correlation of number of observed species (r=0.366, P=0.006) Chao-1-estimator (r=0.352, P=0.008) and BMI (Fig. 1). Furthermore, a higher BMI was related to lower depression scores (r=0.351, P<0.001). Although there was a tendency of a negative correlation of BDI-scores and alpha-diversity (r=–0.180, P=0.059), correlations with depression scores and IPAQ-scores did not reach significance level (Fig. 1).

Our preliminary data demonstrate correlations of alpha-diversity and BMI. Further studies are needed to provide further insights in AN gut microbiota and its influence factors.