Gut Microbiome Changes in Anorexia Nervosa: A Comprehensive Review

Area of Science:

• Microbiome research
• Psychiatric disorders
• Human gut microbiome

Background:

• Anorexia nervosa (AN) presents significant challenges in psychiatric management, with its underlying pathophysiology remaining unclear.
• Emerging evidence suggests a potential role for gut microbiota dysbiosis in AN development and progression.

Purpose of the Study:

• To investigate the association between the human gut microbiota and anorexia nervosa.
• To explore the relationship between gut microbial composition and refeeding syndrome in AN patients (objective 2 was not addressed in the reviewed studies).

Main Methods:

• A systematic review of studies was conducted using MEDLINE and PsycINFO databases.
• Included studies focused on the gut microbiota in patients with anorexia nervosa.
• Data from 14 studies involving 476 AN patients and 554 healthy controls were analyzed.

Main Results:

• Patients with AN exhibited significantly lower levels of *Faecalibacterium prausnitzii* and *Roseburia inulinivorans* compared to healthy controls.
• An increased abundance of *Methanobrevibacter smithii* was consistently observed in AN patients.
• While alpha diversity changes were inconsistent, beta diversity analysis indicated alterations in microbial community structure in AN.

Conclusions:

• Gut microbiota dysbiosis, characterized by specific bacterial shifts, may contribute to the pathophysiology of anorexia nervosa.
• Reduced microbial production of short-chain fatty acids, linked to dysbiosis, could promote a proinflammatory state in AN.
• Microbial alterations might influence energy utilization and endocrine changes, exacerbating semistarvation in AN.