In our urban metropoles, nature is commonly seen as something which happens far away in the spaces between cities, towns and villages. But we are intrinsically - and always have been - a part of nature, though now we are more out of synch with the natural world and exploit and plunder it more greedily than at any time previously in our evolutionary history. We cannot live without nature; it provides all that we eat and drink, the clothes on our backs and the buildings we inhabit. Therefore, by protecting our natural resources, ecosystems and wildlife, we are also protecting and looking after ourselves.
Below we discuss the natural world and its relation to our mental and physical health, delving down to the microbial scale.
“One of the first conditions of happiness is that the link between man and nature shall not be broken.” - Leo Tolstoy
Birdsong - the soundtrack for this page.
The positive benefits that spending time in natural spaces has on our mental and physical health, is now being proven scientifically(1). As all city dwellers know, surrounded by brick, mortar, glass and steel, we yearn to escape to the wide open and natural spaces in order to relax and “unwind”. It’s not a stretch of the imagination to believe that we’ve felt this strong urge since we began settling into towns and cities initially, tens of thousands of years ago. The ancient Japanese practice of Shinrin-yoku or ‘Forest Bathing’, is a form of therapy which recognised that spending time in the woods positively benefited people’s minds, bodies and souls. But exactly how nature influences our wellbeing goes far, far deeper. For instance, the humble Mitochondria is just one example of a bacteria/prokaryote whose ancestors(2) existed as an independent single celled organism but evolved to become endosymbiotic, and is to be found within the cells of most living organisms, including ourselves. Indeed, it’s function in the human body is essential as it acts as the “energy centre” or “powerhouse” within cells, turning the sugars, fats and proteins that we eat, into forms of chemical energy that the body can use. “They also produce chemicals that your body needs for other purposes, break down waste products so they’re less harmful, and recycle some of those waste products to save energy.”(3) The Mitochondria is now classed as an “organelle”, but we have an estimated 100 trillion bacterial cells which reside in or outside our bodies. The ratio of microbiota to human cells is roughly 3:1, and includes populations of fungi, bacteria, viruses, archaea and protists. These harmless microorganisms exist in symbiotic relationships with our cells, performing vital tasks and interactions, without which we simply could not function. We are more microbe than human! “...you are more ‘them’ than you are ‘you’.” This, and considering the fact that the woods, plains, rainforests, deserts, mountains etc. were our homes, it’s not surprising that we are intricately linked mind and body to the natural world. We are a part of it, and it is part of us and it’s our true home. Scientific research proves time and again with discoveries such as the bacteria in soil found to have anti inflammatory and stress-busting properties, that(4) we now lead lives disconnected from nature, to the detriment of our health.
“Microbes are a part of all multicellular organisms, performing a myriad of functions essential to life, including the digestion of nutrients and signaling processes. The microbes that are an integral component of living organisms are referred to as the microbiome. The microbiome is found in creatures as simple as the hydra and as complex as humans, elephants, and trees.”(5)
Much of our understanding of the Microbiota has come from The Human Microbiome Project, which was formed upon discovering that; “The microorganisms that live inside and on humans (known as the microbiota) are estimated to outnumber human somatic and germ cells by a factor of ten.” It is our attempt to understand what makes us human, besides the 20,000 protein-coding genes which form our DNA and which isn’t much greater than genome of a fruitfly!(6) The genomes of the microbiome provide traits that show humans did not evolve on their own; human metabolic features have a blend of human and microbial traits, so the picture of the human body which is emerging is one of a 'supra-organism'.
“The human microbiome is one of the largest organs, weighing approximately two to three kilograms in an adult.”(7) Studies such as this discuss in more depth how bacteria and other microorganisms are intrinsic to the functioning and health of the human body.
Strikingly, our microbiome is as unique as we are. we all have a different “microbiome fingerprint”, all fine-tuned to the environments within (and on the surface of) our bodies, affected by our lifestyles, diet and genetics(8). Even more strikingly, communities found residing in the lush microbial rainforest of our armpit, will differ vastly from a community found in another area. An attempt is underway to map these complex and highly organised communities (Microbial Mapping) to better understand the roles they play out in the areas of the body.
What surprised scientists most is the organised spatial structuring of the microbial communities which appears; “”...like a single cohesive entity, as if each bacterial cell were organized the way cells are in a liver or pancreas. This cohesive group of multiple cell types suggests that a microbial community can “act in a concerted manner to contribute to the normal physiology of its host,”...“You would think you were looking at an organ of the body,””(9)
Outside + Inside
The organs of the digestive system are divided into two parts; the alimentary canal and the accompanying digestive organs (stomach, liver, pancreas + gallbladder). The alimentary canal, which is also called the gastrointestinal (GI) tract or gut, is the entire length of tube that winds through the body from the mouth to the anus. Strange as it may seem, this muscular tube is considered to be outside of the body, because it is open to the external environment at each end. The nutrients and fluids we consume are not really inside the body until they are absorbed into the bloodstream(10). Similar to our skin organ system - but far more significant for our immune health - our guts are the main immunological barrier between ourselves and the outside world.
The ‘Gut Immune System’
The gut microbiome - a vast ecosystem of organisms including bacteria, yeasts, fungi, viruses and protozoans - that reside in our digestive pipes, collectively weigh up to 2kg - more than the average human brain(11)! And these 100 trillion! microorganisms have a profound impact on our immune health. Most of these approximately 100,000,000,000,000 microorganisms in the human gastrointestinal tract live in the colon or lower gut where they break down leftover material which we cannot digest. The microbial communities residing in the more sparsely populated small intestine have adapted to a metabolically faster and more transient life(12).
The gut is the largest and most dynamic immunological environment and organ within the body. “Indeed, gut-associated lymphoid tissue (GALT) is the prominent part of mucosal-associated lymphoid tissue (MALT) and represents almost 70% of the entire immune system; moreover, about 80% of plasma cells [mainly immunoglobulin A (IgA)-bearing cells] reside in GALT.”(13). Thus, 80% of the immune system resides in the gut, lending meaning to the saying “All disease begins in the gut”. This is less surprising when you learn that the gut immune system has a surface area equivalent to that of a small studio flat (100-130 square feet) and that the gut is the largest part of our digestive system, measuring at 12 feet in length.
“Within the GI tract, gut microbes promote peristalsis (the movement of food through the intestines), protect against infection, produce vitamins, and maintain a healthy gastrointestinal mucus layer. Outside the digestive tract, gut microbes influence other organs and tissues through neural networks and signaling molecules. Through these complex communication networks, gut microbes regulate 70 to 80 percent of the immune system…(and)...also modulate the function of the brain, bone, heart, skin, eyes, and muscle tissue.”
“When the gut microbiome is disrupted, processes normally regulated by the gut microbiota, such as immunity and brain function, are impaired. This ultimately may lead to the development of chronic conditions such as autoimmune disease, metabolic dysfunction, and mental health issues, among many other health problems.”(14)
The Gut Barrier
The gut barrier is a functional unit, organised as a multi-layer system, made up of two main components: a physical barrier surface (the gut barrier), which prevents bacterial adhesion and regulates paracellular diffusion to the host tissues - thus acting as a first-line defense against outside microbe threats - and a deep functional barrier, that is able to discriminate between pathogens and commensal microorganisms (such as bacteria), regulating the immune tolerance and the immune response to pathogens.Thus these two gut variables - the intestinal microbiota and the gut barrier - form an immunological barrier and physical barrier which determines the health of the gut and consequently, overall human health(15).
How Microbes Influence Our Health
Microbiota + Medicine
Unsurprisingly - considering they are physically so close - these two gut health variables (the physical gut barrier and microbiome barrier) significantly affect one another. “Several studies have highlighted the role of probiotics in the modulation and reduction of intestinal permeability, considering the strong influence of gut microbiota in the modulation of the function and structure of gut barrier, but also on the immune response of the host.”(15) And so, understanding this complex micro-ecosystem is shedding light on how we can maintain a healthy intestinal barrier (gut) - a topic which is of paramount importance to us all now more than ever as gastrointestinal and autoimmune disorders are becoming increasingly prevalent.
Gut microbiome research is also revolutionising our insight, not only of the gut’s vital role in overall human health, but also of new opportunities for medical science. To give one example, this PNAS article discusses the potential of reprogramming gut microbiome to treat a disease. It’s even been suggested that gut microbiota could even influence our social relationships. Studies in Chimps have shown that; “Social relationships...(could)...shape human health and mortality via behavioral, psychosocial, and physiological mechanisms, including inflammatory and immune responses.” “...recent primate studies indicate that the gut microbiome may also be a biological mechanism linking relationships to health.”(17) This makes sense as bacteria benefit from us being social so that they can spread through human populations(18).
SIBO can also be referred to as Dysbiosis. In the gut, the disruption of the microbiome’s cellular components — or gut dysbiosis — can trigger a range of ailments which have been linked to obesity, dermatitis, autoimmune/allergic diseases, neurological imbalances such as autism as well as chronic gut conditions such as irritable bowel syndrome. Some of these diseases can be cured by the use of probiotics and prebiotics designed to adjust microbial imbalance but are often treated with pharmaceutical medicines which can further disrupt the microbiota(15). Read more on the SIBO/Gut Dysbiosis in Depth section.
Good old Guru Pathik in Avatar the Last Airbender season 2 episode 19, imparts great wisdom; “The greatest illusion of this world is the illusion of separation. Things you think are separate and different are actually one and the same.” Scientific research is finding more and more links and similarities between ourselves and the natural world all the time, opening our minds to the complexities of the other species we share our planet with.
A study by scientists András Zlinszky, Bence Molnár and Anders S. Barfod from Hungary and Denmark, found that trees have a special type of beat or rhythm within them which resembles that of a heartbeat(19). The results revealed that at night while the trees sleep, they often have a beat pulsating throughout their body, regulating their internal rhythms and pumping liquids around the organism, just as hearts do in humans and other living creatures.
Equally amazing is the discovery that plants may have inbuilt compassionate and nurturing behaviours, like we do. It was previously believed that plants were in constant competition with one another, but they found that: “the seedling and nurse were more likely to thrive when grown together, compared to either plant growing alone.”(20)
We share 60% of our genes with the humble, tiny fruit fly(21) and not very long ago we were passive marine sponge-like creatures, leisurely filtering the sea water for particles of food, attached to our rocky cribs(22). There are far more similarities between our species and all those who inhabit this planet, land, sea and air and it’s important to remind ourselves of this fact regularly.
“Humans are not proud of their ancestors, and rarely invite them round to dinner.” - Douglas Adams
Apart from transforming your bedrooms and flats into jungles of beautiful, air detoxifying plants, you don't need to spend money or go far in order to get a dose of nature. While unwell, it can be hard to get out into the big open natural spaces or woods, especially if you don't live in walking distance to any. Of course, nothing can replace actually being surrounded by trees in the woods, forests and fields, but when this is the case, we often watch the below documentary videos which are magical and can transport us away from the hectic world of the urban metropolis. We’ve selected some of our favourites, created by very special individuals and personal heroes of ours. They are all stunning, informative and deeply relaxing (and mostly nature/nature-related).