Environment Key in Shaping the Gut Microbiome

By Lillian So Chan



We know that the gut microbiome plays fundamental roles in physiology and overall health. Now we are learning that we may have more control over our gut microbiome than we previously thought.

A team of scientists from Israel, the Netherlands, and Norway has shown that environment dominates over genetics in shaping our gut microbiome. In a series of studies using different cohorts of study participants, applying different genetic and phenotyping tests, analyzing gut microbes, and evaluating lifestyle and food questionnaires, the scientists examined how strongly the gut microbiome is associated with genetic and environmental factors.

They found that there is significant similarity among the microbiomes of genetically unrelated individuals who share a household; however, no significant similarity was found among relatives who do not have a history of household sharing. These results are in line with previous studies, including a recent twin study that showed the gut microbiomes of twins become more genetically dissimilar over time when twins are living apart. Other findings include:


  • Gut microbiome and host genetics are largely independent of each other. From the results, heritability estimate is only 1.9%, or at most 8.1%. These numbers serve as estimates of the lower and upper bound of the true overall microbiome heritability.
  • More than 20% of microbiome differences among individuals are associated with factors related to diet, medication, drug use, fasting glucose levels, body mass index, glycemic status, cholesterol levels, waist and hip circumferences, waist-hip ratio, and lactose consumption.
  • Gut microbiome measurements and data significantly increased the prediction accuracies of traits such as diabetes and obesity, as compared to methods using only genetic or environmental factors.
  • Improvement of the gut microbiome aimed at improving health and clinical outcomes may be carried out across diverse populations of different genetic backgrounds.
  • The scientists suggest that gut microbiome data is a powerful addition to genetic data in predicting an individual’s phenotypes and health risks.


Although we can’t change our genetics, this study suggests that genetics’ role in our gut health is minimal. We can, however, change diet and lifestyle; their dominant roles in shaping our gut microbiome should be taken into account when we consider improving our health.

About the Author

Lillian So Chan is the founding editor of WellnessOptions, a print magazine and website, and author of the book WellnessOptions Guide to Health published by Penguin Books. With over thirty years of experience in journalism and editing, Lillian has established unique editorial directions for several award-winning publications. She has worked for Maclean’s, Canada's largest news magazine, and served as a Governor and Deputy Chairperson of the Board of Governors at the Simon Fraser University, British Columbia, Canada.

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Resources

Rothschild, D. et al. “Environment dominates over host genetics in shaping human gut microbiota,” Nature. 28 Feb. 2018, https://www.nature.com/articles/nature25973.