Psychoneuroimmunology and the ecology of the body.
Most people have heard of mind-body medicine. The idea that somehow what you think and feel can influence your health. To many people this seems farfetched, an idea that belongs in the worlds of science fiction or perhaps fringe medicine and healers. Nothing could be further from the truth.
Psychoneuroimmunology, and the closely related science of psychoneuroendocrinology is the science behind mind-body medicine. And it's a lot of science, spanning well over 100 years of research.
Psychology is the study of how your body senses both the internal and external worlds. The collection of information that allows your brain to build a picture of what is going on both inside and outside you. With this information it creates a plan to keep the body and mind safe. Vision, smell, hearing, taste and touch are all part of psychology. This picture is a story, the one that runs in your head- your unique perspective of how the world is.
Neurology is the study of how the nerve cells in your body and brains- yes brains, you have two -collect and transmit information around us. The cells of the brains create your story, and so clinical psychology which includes mood and memory along with personality and behaviours are part of neurology. Two brains? Yes one in your head and a second in the wall of your intestine( gut).
Immunology is the study of how our immune cells act as the key workers in our body. The housekeepers if you wish. Fighting infection and cancer are but a small part of the immune system’s function. Most of the cells’ work is much more “mundane”. Like the nervous system much of their existence is spent collecting information from both inside and outside the body, and then sharing this information with the rest of the cells.
For a long time we studied the nervous and the immune systems separately. But we are beginning to recognise that this was a bad idea. In reality they are so closely related in their functions that they effectively act as one system in our body, the neuroimmune system.
If psychology is just a branch of neurology, which it is, and indeed of neuroimmunology, then it make sense that how you think and feel, the story in your head, might influence the rest of the neuroimmune system. This is exactly what occurs, and so how you think and feel has a direct influence on your physical health- mind-body medicine! Psychoneuroimmunology.
And psychoneuroendocrinology? This is a further subcategorisation. In reality the endocrine system, the hormones of the body and the cells that make them are a subset of neuro-immune cells.
Read the science chapter for more details of how this all works and how once you understand this you can change your health!
Of The Body
So you think that you are human? Wrong! Your body is much more complex than that. You are at best about 30 per cent human, and the rest is a complex mixture of microorganisms- bugs if you want. Mostly bacteria, but there are many viruses and fungi and some creepy crawly creatures that live on or with us.
You are a meta-organism, or more correctly, an ecosystem. So what is an ecosystem, you might ask? It's a collection of animals and plants and the space they occupy. The study of ecology is the science that not only catalogues what species are present in the system, but how they interact with each other.
Ecosystems can be very simple or very complex. The human ecosystem is probably the most complex on the planet. As far as we can understand, we appear to be unique in that we can manage time and make decisions. We can plan and directly change our environment. We are also mobile and incredibly adaptable. That is why we have managed to occupy every type of environment on the planet, from scorching deserts and tropical rainforests to the frozen north.
The key to understanding ecosystems is that they are successful only if mutually cooperative behaviours exist between all the different members! That might seem odd when you think of wild animals or insects eating each other, but it's a fact. These are critical to an ecosystem being healthy and thriving.
The human body is the pinnacle of the evolution of cooperation in a single organism. Our body consists of approximately 35 trillion cells. There are about 200 classes of very diverse specialist human cells which can only survive because they work together cooperatively. None can live without the others.
Depending upon where you live, this cooperation extends to a community of between 3000 and 7000 species of bacteria present in the human body. This colony is probably 60-100 trillion cells, outnumbering human cells by two to three. This is not to mention the viruses, fungi, archaea, protozoa, mites, and worms that contribute to your body's entire ecosystem. Although this may be a disquieting thought to many, it's a fact. This group of diverse cells and organisms are obliged to exist in balance and harmony inside us, a super organism. This cooperative harmony is key to being and remaining healthy and well.
So we may think of ourselves as a single unit. However, in reality, we are like a tropical rainforest or coral reef, a highly complex community of widely diverse individual human cells and microorganisms all working in harmony to provide the whole.
Thinking of the body as a dynamic ecosystem can help understand health (and sickness) more comprehensively. Along these lines, the medical and healing communities are developing an appreciation of the exquisite interplay between the various organ systems in the body. For a long time, Western Medicine separated cardiology (heart), neurology (nerves and the brain), gastroenterology (gut and liver), etc., as if they existed in isolation from each other. In reality, all are intimately connected, not only physically, but through an exquisitely complex communication network run by the neurone-immune and neuro-endocrine cells of the body.
If anything goes wrong anywhere in the body, it affects every other system. This happens in seconds and minutes and over hours, days, and years. It is why it is crucial to have a holistic and integrative approach to both achieving health and wellness and treating illness.
It is a common pitfall for many practitioners and their patients to attempt to address illness by treating the individual parts, or from their personal perspective. In part, this occurs because of increasing specialist training in our world. But this type of approach often fails because we must address the problem from a broader perspective.
The Microbiota- the other bit of you
You have been told that bugs, or more correctly bacteria, are nasty. They cause infections, sickness and disease. This is true if you only want to consider the tiniest portion of the bacterial world. In reality, the world would not exist without bacteria. They were some of the first living organisms to inhabit the earth, and if you think we are clever at occupying various spaces, we have nothing on them. They appeared around 3.5 billion years ago and were responsible for making most of the oxygen in our atmosphere, along with the nitrates that all green plants need to grow (fertilizer).
They are the second most abundant organisms on the planet, weighing in total around 70 Giga tons. Plants win the race at 450 Giga tons, and fungi come in third with an estimated weight of 14 Giga tons.
There is a lot of debate about the proportion of the human body made of bacteria, at least in numbers of cells, but the simple answer is a lot. Probably between 50 - 60 per cent. However you look at it, that's a lot. Add in fungi, and the percentage of human cells falls further. But it's not the numbers that are important; it is the amount of genetic material or DNA they contain that is of interest. While we talk about 26,000 human genes, we talk about millions of individual genes in the bacterial colonies vital to our human ecosystem. This enormous library is where much of the human body's genetic information is stored. Data that runs or manipulates many of the systems in our body!
What is essential to recognize is that bacteria did not evolve around us- we evolved around them. They came first. You could argue that bacteria have created and crafted a mobile home.
The largest and most diverse colony lives in our intestine. Mainly the large intestine or colon. These bacteria eat the leftovers from digestion and absorption of food higher up in the intestine. They produce a myriad of different chemicals that influence the rest of the body, including your brain.
They communicate with the rest of the body's cells through chemical messengers that interact with nerve and immune cells (neuroimmune system) located in the wall of the intestine.
There are colonies on and in pretty much every tissue in our body, including cancer growths!
The colony in our intestine is probably one of the most intricate bacterial ecosystems on the planet. A complex ecosystem within an even more complex ecosystem. Truly the pinnacle of millions of years of evolution.
Many things influence the composition of the colony. Your mode of birth, vaginal or c-section. The environment that you grew up in- both physical and emotional. But the most important is how you choose to live your life, your lifestyle. And of your lifestyle, your choice of foods is the critical component. Literally, you are what you eat. The reason- because it shapes the bacterial colony in your gut (and indeed the rest of your body). And this colony runs you.