Contrary to previous findings and believes that the variation in the microbiome is dependent on the host's genetic composition, new study reports that diet and lifestyle are the most dominant factors shaping our microbiome composition. The study was conducted by a research team from the Weizmann Institute of Science and published in Nature.
The question of nature vs nurture extends to our microbiome - the personal complement of mostly-friendly bacteria we carry around with us. Study after study has found that our microbiome affects nearly every aspect of our health; and its microbial composition, which varies from individual to individual, may hold the key to everything from weight gain to moods. Some microbiome researchers had suggested that this variation begins with differences in our genes; but a large-scale study conducted at the Weizmann Institute of Science challenges this idea and provides evidence that the connection between microbiome and health may be even more important than we thought.
Indeed, the working hypothesis has been that genetics plays a major role in determining microbiome variation among people. According to this view, our genes determine the environment our microbiome occupies, and each particular environment allows certain bacterial strains to thrive. However, the Weizmann researchers were surprised to discover that the host's genetics play a very minor role in determining microbiome composition - only accounting for about 2% of the variation between populations.
If microbiome populations are not shaped by our genetics, how do they nonetheless interact with our genes to modify our health? The scientists investigated the connections between microbiome and the measurements in the database of cholesterol, weight, blood glucose levels, and other clinical parameters. The study results were very surprising: For most of these clinical measures, the association with bacterial genomes was at least as strong, and in some cases stronger, than the association with the host's human genome.
According to the scientists, these findings provide solid evidence that understanding the factors that shape our microbiome may be key to understanding and treating many common health problems.
Segal: "We cannot change our genes, but we now know that we can affect - and even reshape - the composition of the different kinds of bacteria we host in our bodies. So the findings of our research are quite hopeful; they suggest that our microbiome could be a powerful means for improving our health."
The field of microbiome research is relatively young; the database of 1,000 individuals collected at the Weizmann institute is one of the most extensive in the world. Segal and Elinav believe that over time, with the further addition of data to their study and those of others, these recent findings may be further validated, and the connection between our microbiome, our genetics and our health will become clearer.