Studies show that microbes present in the human body can detect diseases and problems better than genes
The microbes present in the human body have been linked to many things. Now, scientists say they can reveal a lot about people’s future health. Two new studies reveal that the “microbiome” – the mixture of microbes in our gut – can reveal the presence of disease more effectively than the genes themselves – in addition to anticipating the risk of dying in the next 15 years.
In the first study, the researchers reviewed 47 theses that analyzed associations between the collective genomes of intestinal microbes and 13 common diseases. This included schizophrenia , hypertension and asthma – all considered “complex” because they are caused by environmental and genetic factors. They then compared the results with 24 other studies from the Genomic Association (GWA), which correlated specific human genetic variants with diseases.
Overall, the genetic signature of intestinal microbes was 20% better at detecting a healthy person and a patient than genes, the team reported in an article published this month. The microbiome was 50% more effective than GWA studies in predicting whether someone had colorectal cancer. A person’s genetic profile only surpassed the microbiome by predicting whether someone had type 1 diabetes.
Although the study’s author, Braden Tierney, a computational biologist at Harvard Medical School, admits that the analysis is preliminary, he says the work can benefit people. “We can use the microbiome and human genetics to improve patients’ quality of life.” The goal, he says, is to identify key markers in the two sets of genomes that can help diagnose these complex diseases.
Still, Jeroen Raes, a microbiome researcher at the VIB-KU Leuven Microbiology center, says that scientists don’t know as much about the microbiome as about how human genes work. So comparing the two at this point is “risky”.
In the second study, the researchers looked at the link between a person’s microbiome and its useful life. The analysis took advantage of a Finnish study that has collected health data from thousands of participants since 1972. Since 2002, participants donated sequenced stool samples 15 years later.
The data reveals that individuals with an abundance of “Enterobacteriaceae” bacteria – a family of potentially infectious bacteria that includes Escherichia cole and salmonella – are 15% more likely to die in the next 15 years, the team reported.
It is worth remembering that the link between intestinal bacteria and the increased risk of death occurs in eastern and western Finnish populations, which have different genetic origins and lifestyles.
In both studies, it is still unclear why the microbiome is linked to death and disease. It is possible that microbes are causing problems and shortening someone’s life span. But it is also possible that they are reflecting what else is going on in the body.
In any case, doctors and scientists who want to help prevent and treat human diseases “should pay much more attention to the small residents in our bodies,” says Tierney.