On this World Microbiome Day, we explore the One Health perspective: the idea that human, animal, and environmental health are not separate concerns but expressions of the same interconnected system.

 

What is One Health, and why does it matter to your gut?

At its heart, One Health is the recognition that the health of humans, animals, and ecosystems is closely linked and interdependent1. While we may often think of ourselves as individuals, science now shows we are “holobionts2“,  complex collectives of human cells and trillions of microbes intimately connected to and co-evolving. Bacteria, fungi, viruses, and archaea, are not just passengers. They are active participants in our health, influencing everything from digestion and immunity to mood and metabolism.

These microorganisms also connect us to the world around us as they are the common denominator of life on Earth. Subsets of microbial communities are constantly cycling through our shared habitats. They move from soil and water into plants and animals and ultimately into our bodies before returning to the environment. By functioning as the planet’s invisible engineers3, these microbes bridge the health of the entire biosphere.

 

Your gut microbiome is shaped by the world you live in

Our gut microbiota is far from a closed system. Instead, it continuously interacts with the microbial diversity in our surroundings. The food you eat, the spaces you inhabit, the animals you live with — all of these leave a microbial imprint.

Take soil, for example. Research shows that healthy, diverse soils3 transfer beneficial bacteria to the plants we eat, contributing to the microbial richness of our diet.

Interactions with pets and other domestic animals6 matter too. Living with animals is associated with greater skin and gut microbiome diversity, an effect likely driven by the exchange of microbes through touch, shared spaces, and outdoor environments. And spending time in biodiverse surroundings introduces a wider range of environmental microbes to our bodies in ways that urban and indoor environments simply cannot replicate.

As microbiome researcher Mireia Vallès-Colomer has noted, our microbiomes are continuously shaped and shared through our social networks — from the microbes we inherit from our mothers and families, to those we exchange with friends and pets. Our microbial identity, in other words, is a social and ecological one.

 

Why the same diet affects people differently

One of the most fascinating One Health insights is that our unique microbial makeup dictates how we metabolize what we eat. The same food can have very different effects depending on who is eating it — not because of genetics alone, but because of the microbial community in the gut.

Research shows7 that gut bacteria can convert some compounds into helpful molecules while detoxifying others. For example, when we consume certain plant-based nutrients, only individuals with specific bacterial species can transform those compounds into natural protective agents that inhibit the growth of harmful pathogens like E. coli. This means that the health benefits you receive from a specific food, such as a boost in internal defense, depend entirely on whether your unique microbial community possesses the right tools for the job.

This explains why the exact same diet can have different health effects on different people; it may depend on the microbial community you have.

 

Can microbes help us solve global challenges?

The One Health lens does more than reframe individual gut health. It also reveals the role of microbes in addressing some of our biggest planetary challenges3.

On climate, microbes are central actors: they regulate greenhouse gas exchanges across permafrost, wetlands, and oceans. Innovative microbial feed additives4 for cattle may even reduce methane emissions while improving animal digestion and health.

On antimicrobial resistance, one of the gravest threats5 to global health, maintaining healthy environmental microbiomes can help naturally outcompete dangerous pathogens2, reducing the selective pressure that drives resistance.

And in agriculture, harnessing the natural microbiomes of soils and crops can reduce reliance on chemical fertilizers, making food systems more resilient4 and sustainable.

Across all these challenges, the pattern is consistent: when microbial ecosystems are healthy, broader systems tend to be healthier too.

 

Small steps, big picture

Understanding gut health through a One Health view does not require overhauling your life. But it does invite a shift in perspective — seeing your gut not as an isolated system to be optimized, but as a living interface between your body and the wider world.

Some of the most effective steps are also the most accessible. If you want to support your gut balance, you can start by diversifying your diet. Eating varied foods and fermented products helps seed your gut with beneficial species. It also helps to connect with nature6. Spending time outdoors and living with pets introduces healthy environmental microbes to your skin and gut.

Finally, supporting sustainable practices2 and choosing foods from healthy soil systems helps the microbial cycling that keeps the whole planet stable. On this World Microbiome Day, remember that when we protect our environment’s microbes, we are ultimately protecting our health.

 

References:

  1. Häsler B, Tvarijonaviciute A, Savić S, eds. Principles of One Health for a Better Planet. CAB International; 2025.
  2. Van Bruggen AHC, Goss EM, Havelaar A, et al. One Health – Cycling of diverse microbial communities as a connecting force for soil, plant, animal, human and ecosystem health. Sci Total Environ. 2019;664:927-937. doi:10.1016/j.scitotenv.2019.02.091
  3. Rocke E, Knight R, Ghisleni G, et al. Microbiomes for a stable planet: embedding microbial processes in global climate action. Green Carbon. 2026;1(1):[insert pages]. doi:10.1016/j.greenca.2026.01.001
  4. Proctor LM, Dore J, Maguin E, et al. Integrating microbiomes into One Health: insights from the 2025 One Health World Microbiome Partnership Summit. Lancet Microbe. 2026;7:101319. doi:10.1016/j.lanmic.2025.101319
  5. Aslam B, Khurshid M, Arshad MI, et al. Antibiotic resistance: One Health One World outlook. Front Cell Infect Microbiol. 2021;11:771510. doi:10.3389/fmicb.2021.771510
  6. Trinh P, Zaneveld JR, Safranek S, Rabinowitz PM. One Health relationships between human, animal, and environmental microbiomes: a mini-review. Front Public Health. 2018;6:235. doi:10.3389/fpubh.2018.00235
  7. Culp EJ, Nelson NT, Verdegaal AA, et al. Microbial transformation of dietary xenobiotics shapes gut microbiome composition. Cell. 2024;187(22):6327-6345. doi:10.1016/j.cell.2024.08.038