Hair loss can be due to several causes including genetic proclivity (esp. male pattern baldness), micronutrient deficiencies (such as a zinc deficiency) or to an autoimmune inflammatory disorder such as alopecia areata (which also has nutritional and environmental co-factors).
In alopecia, the gut biome is thought to play a similar role as it does in other inflammatory disorders.1 While diversity does not appear to differ between alopecia and controls, there may be greater abundance of Holdemania filiformis, Erysipelotrichacea, Lachnospiraceae, Parabacteroides johnsonii, Eggerthellaceae, Clostridiales vadin BB 60 group, Bacteroides eggerthii and Parabacteroides distasonis.2
In a report of 2 case studies, patients with alopecia had reduced hair loss after receiving faecal microbiome transplants (for clostridium dificile infection and Crohn’s disease respectively).3
1. Borde A, Åstrand A. Alopecia areata and the gut—the link opens up for novel therapeutic interventions. Expert Opinion on Therapeutic Targets. 2018;22(6):503-11.
2. Moreno-Arrones OM, Serrano-Villar S, Perez-Brocal V, Saceda-Corralo D, Morales-Raya C, Rodrigues-Barata R, et al. Analysis of the gut microbiota in alopecia areata: identification of bacterial biomarkers. Journal of the European Academy of Dermatology and Venereology. 2020;34(2):400-5.
3. Rebello D, Yen E, Lio P, Kelly CR. Unexpected Benefits: Hair Growth in Two Alopecia Patients after Fecal Microbiota Transplant: 1383. American Journal of Gastroenterology. 2016;111:S623-S4.