The human microbiome is composed of thousands of different species of bacteria and fungi that seem to influence virtually every function in the human body from digestion and metabolism to fighting disease. These crucial microbial communities might even be able to predict the future, according to two new studies published this month.
The analyses are both preliminary. But interesting, nonetheless. And just like other research on the microbiome, hint at the potential therapeutic and diagnostic power of the microbiome.
One of the studies, published on 2 January in bioRxiv, showed that gut microbes could potentially be used to differentiate between a healthy person and someone with a disease (1). The authors looked to 47 previously published studies that investigated associations between genomes of the gut microbes and 13 common diseases, including schizophrenia, hypertension, and asthma, which were compared with 24 genome-wide association studies (GWAS).
Human genes have been scrutinized for decades. However, much less is known about the microbiome. So, in this respect, there is no comparison between the two. So, in this respect, there is no comparison between the two. However, Braden Tierney, a computational biologist at Harvard Medical School told Science: “We can use both the microbiome and human genetics in the clinic to improve patient quality of life”.
The authors focused on these so-called ‘complex’ diseases, i.e. influenced by an array of genetic and environmental factors but which scientists still do not fully understand the underlying causes. Unravelling both the genetics and the role of the microbiome might help build new tools and therapies to combat complex human diseases.
Predictions made using genes of the gut microbiome were 20 per cent better than the person’s own genes. And the number jumped up to 50 per cent when predicting whether a person has colorectal cancer. An individual’s own genome only outperformed the microbiome in predicting type 1 diabetes.
The other study, published on 13 January in MedRxiv showed that the gut microbiome can predict a person’s risk mortality, to some degree (2). This time the researchers turned to a Finish study — human health data collected from thousands of participants since the early 1970s — to come with their findings.
They discovered that individuals with an abundance of bacteria from the Enterobacteriaceae family, which include Escherichia coli and salmonella, are 15 per cent more likely to die in the next 15 years. The risk was consistent across eastern and western Finnish populations, which have different lifestyles and genetics.
Imbalances in the microbiome may be the source of many health problems, which means it might also be a useful barometer of health and disease. However, while it is altogether possible that the gut microbiome can affect a person’s health, it is also equally possible that the health of an individual will influence microbial communities. The authors also point out that since the microbiome is highly influenced by environmental facts, it might be a better predictor of certain diseases like, say, type 2 diabetes.
The research is still in the early stages and the studies have not yet undergone rigorous peer review. So, there is still plenty to do in this relatively nascent, yet clearly important, area of medicine.
(1) Tierne, B.T. et al.The predictive power of the microbiome exceeds that of genome-wide association studies in the discrimination of complex human disease. bioRxiv (2020). DOI: 10.1101/2019.12.31.891978
(2) Salosensaari, A. et al. Taxonomic Signatures of Long-Term Mortality Risk in Human Gut Microbiota. MedRxiv (2020). DOI: 10.1101/2019.12.30.19015842