Soil, Microbes, and Human Health: One connected system

Shared biology: soils and human health

One example involves the human gut microbiome: the community of microorganisms living in our digestive system. These microorganisms contribute to digestion, nutrient processing, and immune system function. Although the gut microbiome is influenced by many factors, including diet and lifestyle, it is also linked to the environments in which people live. Food, water, and contact with natural environments expose humans to diverse microorganisms that may contribute to the composition of the human microbiome (Banerjee & van der Heijden, 2023). For instance, research points to a gradient of diverse microbiome in traditional populations and hunter-gatherer societies who live in close contact with soil towards people living in industrialised settings (Keiblinger et al., 2022).

Scientists have also investigated how reduced contact with biodiverse natural environments may affect immune system development. According to the biodiversity hypothesis, exposure to a wider range of environmental microorganisms can help regulate immune responses. Reduced exposure has been discussed as one possible factor contributing to the increasing prevalence of allergies, asthma, and other inflammatory conditions observed in some societies (Wall et al., 2015).

For great visualisations of these relationships, have a look at Figures 1 and 2 in the articles by Hirt (2020), Banerjee & van der Heijden (2023), or Ma et al. (2025), respectively.