The Human Microbiome & the Wilderness Within

We consider natural wilderness to be the wild places in nature and ignore the desolate wilderness that is the urban areas we live in. There is another wilderness hiding in plain sight and that is the wilderness within. Scientists have identified a number of human body systems and more recently, the human microbiome.

The human microbiome

The skeletal system is the bone structure of the body that is held together by tendons, ligaments, and cartilage. The nervous system transmits nerve impulses throughout the body that enable us to function. The muscular system includes skeletal muscles, organ muscles and cardiac muscles. The respiratory system takes in oxygen and expels carbon dioxide.

The endocrine system is a collection of glands that secrete hormones into the circulatory system to be delivered to the body’s vital organs. The immune system defends the body against pathogens. The cardiovascular and circulatory systems transport nutrients, oxygen, carbon dioxide, hormones, and blood cells where needed. The urinary system helps eliminate waste products from the body. The integumentary system includes human skin, hair and nails.

The reproductive system is a combination of bodily organs and tissues used in the process of creating children. The digestive system breaks down food, extracts nutrients into the bloodstream, and excretes waste. It is clear that these systems are interconnected and interdependent on many levels, all working to maintain homeostasis which is the body’s dynamic balance. These body systems are complex organisms made up of two hundred different types of cells, thirty trillions cells in all.

Apart from the body systems’ cells, our bodies also house the microbiome that is largely made up of bacteria, fungi, protozoa and viruses. The microbiome was not generally recognized to exist until the late 1990s. The microbiome is essential for human development, immunity and nutrition. A number of diseases are associated with deficiencies in the microbiome.

The bacteria living in and on us help us digest our food, regulate our immune system, protect against other harmful bacteria and produce vitamins. The latest scientific estimate for the number of bacteria in a human body is thirty eight trillion. Every human has fungi as part of their microbiota. The total number of fungal cells is orders of magnitude smaller than that of the bacterial microbiota.

The largest members of the microbiome are however, viruses. It will certainly surprise you to learn that there are as many as three hundred and eighty trillion viruses living within each one of us. These viruses are not the ones that sometimes cause us to cough or sneeze, such as the flu or common cold viruses. We have very little insight into their purpose or function except that many of these viruses interact with the bacteria in the microbiome.

Armed with this knowledge we can see that we have a symbiotic, and therefore beneficial, relationship with the microorganisms inside and on our bodies. Certain microorganisms perform tasks that we know to be useful to us, however the role of most of them is not well understood. The collection of microbes that live inside each and every one of us has evolved with us over millions of years. The number of genes in one person’s microbiome is two hundred times the number of genes in the collective human genome. The microbiome may weigh as much as 2.3 kg and microbe cells outnumber our human cells thirteen to one.

The human microbiome

It is not logical that we should draw dividing lines between our body’s microbiome and the human organs and systems as they are all inside our bodies and clearly all are necessary to keep us alive. Each person is a biological organism with an internal web of life that is similar to, and resonates with, the external web of life. It is for this reason that people are healthier when living in a healthy environment. If we wish to talk about the biological systems that make us human, we should also be prepared to breach the mental barriers that make us think that we are different and separate from other life forms.

Our bodies are complex organisms and the nature of complex systems is that they are unpredictable and defy intellectual, and therefore technology-mediated, understanding. We do have the capacity to understand our own bodies. It starts by taking personal responsibility for our health and deepening our understanding of the wilderness within. We should make informed health choices and take back control. Our body, our choice.

This article has been published in the Senior Times of the Times of Malta of the 20 November 2021

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