Health professionals often stress the importance of a healthy gut microbiome. However up to now the question what constitutes a healthy intestinal microbiome remains unanswered. That is why researchers from UMCG, Utrecht University and UMC Utrecht identified links between dysbiosis and genetics, childhood- and environmental factors, lifestyle and socioeconomics. Interestingly, their study shows that living environment and lifestyle have a greater influence on the gut microbiome than our genetics. Their detailed analysis is recently reported in Nature.
Dutch Microbiome Project (DMP)
To address these issues, the researchers generated and analyzed a large, multi-generational gut microbiome cohort; the Dutch Microbiome Project (DMP) cohort. This cohort was developed as a part of Lifelines cohort study. Lifelines is a prospective population-based cohort study to examine health and health-related behaviors in 167.000 people living in the northern Netherlands. To form the DMP cohort, 8719 distinct fresh-frozen fecal- and blood samples were collected from participants in good health and with a variety of diseases from 2756 families. Information collected from the participants was grouped into several categories like family structure, diseases, gastrointestinal complaints, general health score, medication use, birth-related factors, reported childhood (< 16 years) exposures, environmental factors (air pollutants, greenspace, urbanicity, pets and smoking), socioeconomic characteristics and diet. Gut microbiome parameters were then compared to 241 of the collected health and lifestyle factors.
Heredity less important than expected
The most important observation of the researchers is that the microbiome is shaped primarily by the environment and the people they share a household with (48,5%), regardless of whether they are related or not; only around 6,5% of the microbiome composition is heritable. By comparing associations between microbiome, health and diverse diseases, the researchers were able to identify a common signal for gut dysbiosis. Based on this general pattern of a “unhealthy” microbiome, the researchers were able to find the pattern and characteristic features of a “healthy” gut microbiome. They observed that a healthier diet, childhood and current exposures to rural environment and pets, exposure to green space and higher income share signals with healthy microbiome patterns. At the same time they established that factors like smoking, a high-carbohydrate diet and exposure to NO2 and small particulate matter are positively correlated with disease-linked species, like Clostridia and Ruminococcus.
Interestingly, there were also participants who showed a disease-like microbiome, while not reporting diseases or medication use. This indicates that it is possible that the gut microbiome might detect disorders in the pre-clinical stage.
What does this mean in practical terms?
Whereas the classic hygiene hypothesis focuses on pathogens and early-life exposures, these results suggest that adult exposures also contribute to healthy or unhealthy microbiome patterns and that the environment shapes the microbiome throughout life. This means that it is never too late to use interventions in the areas of nutrition, lifestyle, environment, pro- and prebiotics to influence intestinal health and thus overall health.
Reference: Gacesa, R., Kurilshikov, A., Vich Vila, A.,et al. Environmental factors shaping the gut microbiome in a Dutch population. Nature, 2022, 604.7907: 732-739. DOI: 10.1038/s41586-022-04567-7