Suffering from asthma? You gut may be the therapeutic goldmine you need. Researchers have found evidence that changes in the microbiota shape our risk of asthma, as well as its pathogenesis. Crucially, the first days of life have a major impact on whether we develop asthma. Here are the latest research findings that can potentially help you fight asthma.

By Emilie Korsgaard Andreasen Numerous new studies on allergies have focused on the human gut microbiome, and a range of illnesses appear to be affected by dysbiosis of our gut microbes. Gastrointestinal, metabolic and psychiatric diseases have all been connected to the microbiota1. Now, scientists are turning to the microbial composition to develop treatments for asthma.

Making the first year count

The first indication of who might end up with asthma is at infancy. Still, just how important are the first days of a person’s life when it comes to the microbiota composition? Quite important, it turns out. A study from 2018 found that the composition of the human gut microbiome matures within the first years of life. By testing 690 participants, the researchers were able to link the gut microbial composition at age 1 with a risk of asthma at age five, in children with an immature microbial composition. Turns out the children with increased risk of developing asthma at age 5 had a higher abundance of Veillonella and a lower abundance of Roseburia, Alistipes and Flavonifractor, when they were one. They also found that this tendency is only apparent when the mothers also had asthma, indicating that lacking a microbial community may stimulate the inherent asthma risk. With proper maturation of the gut microbiome in the predisposed children, they may even be able to avoid developing asthma2.

The first indication of who might end up having to deal with asthma is at infancy.

The study argues that several factors may play a central role in shaping the microbiome of young children in their first year: mode of birth delivery, use of  antibiotics in the first year of life and having older siblings, who may transfer their microbiota to the younger sibling and mature their gut composition. These can all influence the risk of developing asthma2.

Gut bugs as treatment

Chances are that you’re already well past your first year of living, and in that case, there's not much that can be done in that regard. However, that doesn’t mean that you should discard your microbiome completely in terms of asthma treatment. It has been indicated that the potential mechanisms driving the relationship between asthma and your gut microbes are the amount of short-chain fatty acids (SCFAs) in your gut. For instance, one study showed that, by increasing fiber intake, the generation of specific SCFAs increased, and went on to shape naïve immune cell responses in return. What's more, histamine and tryptophan metabolites have also been implicated in the mechanisms of asthma3.

Potential mechanisms driving the relationship between asthma and your gut microbes are the amount of short-chain fatty acids (SCFAs) in your gut.

Probiotic treatments as therapy for allergic diseases are promising, however, the probiotic treatment of asthma has been inconclusive. In mouse models, strains like Lactobacillus rhamnosus GG have been shown to decrease airway inflammation, but in clinical trials, no evidence for a positive effect have been found yet3.

The future of asthma treatment

The current evidence suggests that the gut and respiratory microbiota is shaping asthma pathogenesis in childhood, nevertheless, how that is expressed later in life is still unclear. Findings in adult studies also implicate the microbiome with asthma, although figuring out exactly how has been difficult3. Future work will need to consider how the microbiome affects allergies like asthma, which could then lead to treatment options in the future. One thing is clear: scientists are optimistic and stress the importance of continued work in the field to make sure that new therapeutic options are explored.
References
  1. Malan-Muller, S. et al. (2018) The Gut Microbiome and Mental Health: Implications for Anxiety- and Trauma-Related Disorders. OMICS. 22(2);90-107.
  2. Stokholm, J. et al. (2018) Maturation of the gut microbiome and risk of asthma in childhood. Nature Communications. 9;141.
  3. Huang et al. (2019) The microbiome in asthma. Annals of Allergy, Asthma & Immunology. 122(3);270-275.