In humans, the “microbiome” typically refers to the microbial communities that inhabit specific body regions, such as the nasal passages, skin, reproductive, and gastrointestinal tract. Remarkably, the human body harbors around 100 trillion microbial cells. This is roughly three times the number of human cells – and a collective microbial genome that contains about 150 times more genes than our own DNA – in the region of 3.3 million unique microbial genes. This vast gene pool has led scientists to regard the microbiome as the body’s “last organ”.
Understanding the Microbiome
The gut microbiome alone comprises over 1,000 bacterial species and 7,000 distinct strains, and it evolves throughout life in response to various environmental factors, such as diet, exercise, medication, and other exposures. Lifestyle factors such as stress, sleep, physical activity, and hygiene practices further influence its composition.
Chronic stress and poor sleep, contribute to disruptions to the microbiome and have been linked to chronic diseases such as inflammatory bowel disease, Type II diabetes, and cardiovascular conditions.
Shift in perception
The invention of the microscope in the 17th Century opened the door to an invisible microbial world. Initially, microbes were primarily associated with disease. However, environmental microbiology later revealed its beneficial roles, marking a significant paradigm shift.
It’s now widely accepted that all eukaryotes, including humans, function as meta-organisms – inseparable from their associated microbiota. Importantly, pathogenic microbes represent only a small fraction of the microbial world. Loss of microbial diversity, or dysbiosis, can disrupt immune function and create opportunities for disease-causing organisms to emerge.
Dysbiosis is disruptive
Early medical understanding emphasized eliminating microbes, leading to the widespread use of antibiotics. While antibiotics are essential for combating bacterial infections, their broad-spectrum activity can disrupt the balance of the gut microbiota by killing both harmful and beneficial bacteria.
This disruption can lead to dysbiosis, reducing microbial diversity and resilience, and increasing susceptibility to infections, metabolic disorders, and other health complications.
However, we’ve since recognized the importance of commensal and mutualistic microbes for human health. The gut microbiome, for instance, plays critical roles in digestion, immune regulation, pathogen defense, and the synthesis of vitamins and short-chain fatty acids.
With roughly 70% of the immune system located in the gut, the gut-brain axis underscores the connection between gut health and mental wellbeing, affecting mood and cognitive function. Similarly, skin microbes contribute to maintaining hydration by breaking down lipids into natural moisturizers.
Traditional medicine and internal ecosystems
Interestingly, traditional-medicine systems such as Ayurveda, homeopathy, Unani, traditional Chinese medicine, and African indigenous medicine have long emphasized the balance of internal ecosystems. These systems often use natural remedies derived from plants, herbs, minerals, and animal products that can modulate the microbiome and correct dysbiosis.
Furthermore, the gut microbiome actively participates in metabolizing these compounds, influencing their efficacy and bioavailability. Modern research, aided by high-throughput sequencing, is beginning to unravel the complex interactions between these remedies and host-microbiome dynamics.
Broader issues
As our understanding of the human microbiome continues to deepen, it becomes increasingly clear that its composition and function are intricately tied to broader environmental and societal dynamics. One of the most pressing challenges of our time is climate change.
Rising temperatures, altered rainfall patterns, increased frequency of extreme-weather events, and declining soil health are all forcing changes in where and how crops are grown. It is poised to significantly influence agricultural practices, altering crop patterns, the nutritional quality and diversity of food, and, ultimately, food availability.
Eating for better gut health
Crops subjected to climate stress often exhibit reduced levels of essential nutrients such as zinc, iron, and protein. Simultaneously, the narrowing of crop diversity can lead to more homogenized diets, lower fiber intake, and a reduction in the variety of plant-based compounds, vital for supporting a diverse and resilient gut microbiome.
The gut microbiome thrives on dietary diversity and nutrient density. A shift towards calorie-dense but nutrient-poor diets, which may become more common as food systems are pressured by climate change, can lead to gut microbial imbalances or dysbiosis.
Thus, these shifts can have a direct impact on the gut microbiome, with downstream effects on a range of health issues, from metabolic and inflammatory disorders to weakened immunity and impaired mental health.
Moreover, communities already vulnerable to food insecurity are at greater risk for both malnutrition and microbiome disruption, potentially widening existing health disparities. These risks highlight the urgency of adopting a future-oriented, systems-level perspective – one that sees climate, agriculture, diet, and human biology not as isolated elements, but as interconnected parts of a larger health ecosystem.
Gut health and climate change
To prepare for the health challenges of a changing planet, we must develop strategies that preserve agricultural biodiversity, promote sustainable and climate-resilient farming, and ensure access to nutrient-rich, microbiome-supportive foods.
Investing in the well-being of future generations to come
A future-facing, integrative approach is therefore essential – one that recognizes and prepares for the complex interplay between climate change, evolving dietary and lifestyle habits, and the human microbiome. Addressing this interconnected climate-food-lifestyle-microbiome-health axis will not only enhance our ability to mitigate the health consequences of environmental disruptions but also help us to design resilient food systems, personalized nutrition strategies, and adaptive healthcare frameworks.
Investing in this systems-level understanding today is not just a scientific imperative, but a vital strategy for securing the well-being of future generations.
Who is the author?
Shruti Singh is pioneering efforts to transform holistic well-being through innovative, technology-driven solutions.
With a PhD in Biochemistry and an MBA, she integrates scientific insight with strategic implementation to design sustainable, preventive healthcare models.
THE LONGEVITY ANNUAL PRINT EDITION
This article is extracted from our annual print edition. The”Back to Earth” issue is Longevity’s must-have edition for anyone ready to reflect on what we put in and on our bodies. The print edition is available at selected outlets in South Africa. You can also buy a digital copy at Zinio.com.
