Written By Andrea McBeth
Chapter 1: A Story of Co-Evolution and Missing Links
Imagine a world where humans and bacteria have been intertwined since the beginning of time. Billions of years ago, as life emerged on Earth, bacteria and single-celled organisms paved the way for the evolution of complex organisms. This remarkable journey of co-evolution has shaped the intricate relationship we have with our microbiomes.
One significant recent discovery in understanding this co-evolutionary story is the identification of a specific archaea, part of the distinct group of microorganisms separate from bacteria and eukaryotes. This archaea named Loki after the Greek god of mischief was identified as a missing link, connecting the bacterial world to the emergence of multicellular organisms. It is theorized that this Loki organism consumed or endosymbiosed a bacteria and instead of dying they just started living together eventually evolving into multicellular organisms like us. Mitochondria, often referred to as the powerhouse of our cells, were once these free-living bacteria that formed a symbiotic relationship with our ancestors. Similarly, chloroplasts, found in plant cells, originated from photosynthetic bacteria.
This co-evolution has allowed our biology to incorporate essential components from bacterial partners within the human microbiota. It highlights the interdependence and mutual benefits between humans and the trillions of microorganisms residing within and on us. We have been living with them since the beginning of time and it makes total sense that the bacteria that call us home in our microbiome are similarly fundamental to our health and well being. We have been speaking and tweaking each other's behaviors for a very long time.
Chapter 2: The Role of Bacteria in Shaping Ecosystems
Bacteria, with their remarkable adaptability and metabolic capabilities, play an essential role in shaping both the global and our internal ecosystems. 350 million years ago after the emergence of plants but before us mammals came on the scene the planet was covered in trees. They would grow and fall, but nothing was breaking them down. Then some bacteria evolved the ability to break down lignin, a complex compound found in plant cell walls. Lignin degradation is critical for the carbon cycle and the balance of terrestrial ecosystems. Certain bacteria have evolved specialized enzymes that can break down lignin, unlocking its energy and facilitating the recycling of organic matter. This transformed the planet's ecology and paved the way for our evolution.
Bacteria now participate in many intricate symbiotic relationships with various organisms in the soil and other important parts of our ecosystems. For example, nitrogen-fixing bacteria form a partnership with leguminous plants, converting atmospheric nitrogen into a form that plants can use for growth. This mutualistic relationship benefits both the bacteria and the plants, enhancing the fertility of the soil and supporting the growth of diverse ecosystems.
Similarly, bacteria are instrumental in our own metabolic processes. In our gut, they aid in the digestion of dietary fiber breaking down many components of the plant material, not just lignan. When they do this they produce beneficial byproducts such as short-chain fatty acids and other postbiotics. These compounds provide energy for our cells, contribute to gut health, and have systemic effects on our overall well-being acting as hormonal regulators. Bacteria are involved in the production of vitamins, such as B vitamins and vitamin K, which are essential for our health. Their role in fermenting and breaking down complex carbohydrates allows us to extract nutrients from our diet effectively.
Chapter 3: The Disappearing Microbiota, Biodiversity Loss, and Chronic Disease
In the modern Western world, our microbiomes are facing a parallel to the loss of biodiversity on our planet. The choices we make and things we are exposed to, from antibiotics, pesticides, and xenobiotics to our hygiene practices and dietary habits, have disrupted the delicate balance of our gut ecosystems. As a result, we are experiencing a massive decline in microbial diversity.
Our diets have undergone a significant transformation since the industrial revolution, becoming more processed and lacking in fiber and plant-based materials. It is suspected that humans on average used to consume upwards of 100 grams of fiber a day based on evidence from current day hunter-gatherer communities like the Hadza. Today the average American gets 6-10 grams of fiber and the dietary recommendations are only 20-30 grams. This shift has starved our gut bacteria of their preferred fuel, further exacerbating the loss of microbial diversity.
The consequences of this biodiversity loss are profound. Research suggests that the decline in gut microbiome diversity is strongly correlated with an increased risk of allergies, inflammatory bowel diseases, metabolic disorders, and even mental health conditions. The Western world is grappling with epidemics of chronic diseases that were once relatively rare in traditional societies.
However, we must not lose hope. By recognizing the link between microbiome diversity and disease, we can take proactive steps to restore and support our gut ecosystems. Embracing a diet rich in whole, unprocessed foods abundant in fiber and plant-based materials can help nourish our gut bacteria and promote the growth of diverse microbial populations.
The remarkable adaptability of bacteria inspires us. Just as they evolved to break down lignin and contribute to ecosystem balance, they hold immense potential to help us address the chronic disease epidemics we face today. By giving our microbiomes the opportunity to thrive, we create conditions for beneficial bacteria to evolve and contribute to our overall health.
In this journey, dietary supplements can play a valuable role in supporting the microbiome. Prebiotics, postbiotics, and other microbiome-focused supplements provide targeted support, but they should complement a healthy diet and lifestyle.
As we embark on the path of microbial diversity stewardship, we become active participants in our own health and the health of the planet. By fostering a harmonious relationship with our microbiomes, we unlock the potential for improved well-being and resilience.
References
Senizza, A., Rocchetti, G., Mosele, J. I., Patrone, V., Callegari, M. L., Morelli, L., & Lucini, L. (2020). Lignans and Gut Microbiota: An Interplay Revealing Potential Health Implications. Molecules , 25(23). https://doi.org/10.3390/molecules25235709
Watson, T. (2019, May 14). The trickster microbes that are shaking up the tree of life. Nature Publishing Group UK. https://doi.org/10.1038/d41586-019-01496-w
Vera-Santander, V. E., Hernández-Figueroa, R. H., Jiménez-Munguía, M. T., Mani-López, E., & López-Malo, A. (2023). Health Benefits of Consuming Foods with Bacterial Probiotics, Postbiotics, and Their Metabolites: A Review. Molecules , 28(3). https://doi.org/10.3390/molecules28031230
Pontzer, H., Wood, B. M., & Raichlen, D. A. (2018). Hunter-gatherers as models in public health. Obesity Reviews: An Official Journal of the International Association for the Study of Obesity, 19 Suppl 1, 24–35.
Fragiadakis, G. K., Smits, S. A., Sonnenburg, E. D., Van Treuren, W., Reid, G., Knight, R., Manjurano, A., Changalucha, J., Dominguez-Bello, M. G., Leach, J., & Sonnenburg, J. L. (2019). Links between environment, diet, and the hunter-gatherer microbiome. Gut Microbes, 10(2), 216–227.
Blaser, M. J. (2017). The theory of disappearing microbiota and the epidemics of chronic diseases. Nature Reviews. Immunology, 17(8), 461–463.
Key Points:
- Humans and bacteria have co-evolved since the beginning of time, shaping our biology and health.
- The discovery of archaea and the role of Loki highlight the missing links connecting bacteria to the emergence of complex organisms.
- Bacteria play vital roles in shaping ecosystems, from breaking down lignin to supporting nutrient absorption and vitamin production in our bodies.
- The modern Western world faces a decline in microbial diversity due to factors like processed diets and unnecessary antibiotic use.
- This loss of diversity is linked to a rise in chronic diseases such as allergies, inflammatory bowel diseases, and metabolic disorders.
- Nourishing our gut bacteria through a diet rich in whole, unprocessed foods can support microbial diversity and overall health.
- Microbial diversity stewardship is essential in restoring and preserving our gut ecosystems.
- Dietary supplements like prebiotics and postbiotics can complement a healthy lifestyle in supporting the microbiome.
- By embracing microbial diversity stewardship, we actively participate in our own health and contribute to the well-being of the planet.