Gut and hair connection? New study identifies specific gut microbiota linked to patchy hair loss

AA is a common form of non-scarring hair loss, marked by autoimmune dysfunction and typically presented as isolated patches of hair loss.

It impacts approximately 2% of people worldwide, showing no bias based on age, gender, or ethnicity, and its onset is known to be very unpredictable.

While previous studies have hinted at a connection, the link between gut microbiota and AA remained relatively unexplored, said researchers.

This new study looked at the relationship between the diversity of the gut microbiota and the condition.

The results identified that certain types of gut bacteria were associated with a lower risk of AA. This included butyricimonas, enterorhabdus, eubacterium (xylanophilum group), and phascolarctobacterium.

On the other hand, Ruminococcaceae UCG003 seemed to be associated with the increased risk of AA despite its positive impacts on various conditions such as chronic insomnia and cardiovascular metabolic disorders.

The researchers leveraged data from the MiBioGen and FinnGen consortiums' Genome-wide association studies (GWAS) encompassing gut microbiota (n = 13,266) and AA (n = 211,428) datasets.

The findings were derived using Mendelian randomisation (MR).

The study was conducted by a team from Zhejiang University School of Medicine, Zhejiang Chinese Medical University, and the Third People's Hospital of Hangzhou.

Multiple elements at play

The study also looked at previous research to further support their findings.

For instance, some studies had shown that the presence of Phascolarctobacterium in healthy individuals might protect against AA – possibly influenced by eating cruciferous vegetables.

On the other hand, Ruminococcaceae UCG003, known for its positive effects on various health conditions, appeared to be a risk factor for AA in this study.

The researchers acknowledged the complexity of the interactions within the gut microbiota.

Certain studies have shown that short-chain fatty acids (SCFAs), produced by certain bacteria in the gut, like butyricimonas, can affect how the body responds to inflammation.

The researchers noted that this connects with the idea of the gut-skin axis and proposed that these fatty acids might play a role in how AA develops by influencing the balance of certain immune cells.

However, the fact that Ruminococcaceae UCG003, which also produces these fatty acids, appears to increase the risk of AA suggests that there are complicated interactions happening within the community of gut bacteria.

While the study concluded that specific types of gut bacteria might be linked to AA and provide potential clues for treatment and prevention.

However, more research is needed to fully understand the complex mechanisms at play, they said.

“Our analysis suggests probable causality between certain gut microbiota and AA, shedding light on its pathogenesis and potential intervention strategies…Future research should focus on a more diverse population and deeper microbial taxonomy to further understand gut microbiota's role in AA.”​

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Exploring the link between gut microbiota and alopeciaareata: a two-sample Mendelian randomization analysis​

Source: International Journal of Dermatology

Authors: Wen Xu, Li Zhang, and Xiuzu Song

https://doi.org/10.1111/ijd.17032​