Weizmann scientists say lifestyle tops genes when it comes to the gut

Genetics plays only a minor role in determining the composition of the mostly friendly bacteria in our digestive systems that apparently determines much about our health, from weight to moods, according to new research at the Weizmann Institute of Science, Rehovot.

The finding, just published in the journal Nature, counters the widespread belief, based on numerous studies, that genetics largely decides the makeup of the human microbiome.

Research students Daphna Rothschild, Dr. Omer Weissbrod and Dr. Elad Barkan, from the lab of Prof. Eran Segal of the computer science and applied mathematics department, found that genetics accounts for only 2% of the variation among populations. Working together with members of Prof. Eran Elinav’s group in Weizmann’s immunology department, the team investigated the question of nature vs nurture in determining each of our unique microbiomes. The Rehovot researchers challenged the old theories and provided evidence that the connection between the microbiome and health may be even more important than previously thought.

Their findings were based on a unique database of some 1,000 Israelis in a longitudinal study of personalized nutrition. Israel has a highly diverse population, which presents an ideal experimental setting for investigating the effects of genetic differences. The scientists investigated the connections between the microbiome and the measurements in the database of cholesterol, weight, blood glucose level and other clinical parameters. In addition to genetic data and microbiome composition, the information collected for each participant included dietary habits, lifestyle, medications and additional measures. The scientists concluded that diet and lifestyle are by far the dominant factors shaping our microbiome composition.

“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,” said Segal. “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, and the database of 1,000 individuals at the Weizmann Institute is one of the world’s most extensive. Segal and Elinav believe that over time, with the further addition of data to their study and those of others, their recent findings may be further validated, and the connection between our microbiome, our genetics and our health will become clearer.