“The Immune Mind” is about the bidirectional relationship between the immune system and the mind. In that, the book is very similar to “The Biology of Belief.” It discusses the need to shift from Western medicine to Eastern medicine, such as Ayurveda or Chinese medicine. Also, a version of “The body“. The complexity of the systems in our body. The immune-brain loop. Hidden anatomy (we still do not understand many things in our bodies). And how intelligent our internal systems are. For example, smell and sight as super sensors of disease.
Exteroception, interoception and predictive processing
At its core, predictive processing posits that our brain generates a model of the outside world, which it constantly builds on and updates. What you just perceived was not reality but instead your brain’s inference – its best guess – of what it expected to see. Predictive processing is actually a rational, clever and extremely energy-efficient way of running a processing machine. Predicting and adjusting is better than constantly reacting.
Feelings
Feelings that stem from inside your body – such as from your heart or your intestines – are your brain’s best guess of the state of your internal world. Just like exteroception, interoception is the predictive brain trying to make meaning from the mess of sensory information. Emotions are goal-directed, the ultimate goal being the minimisation of uncertainty and a balanced state of homeostasis in the body. Hence, mind over matter, the importance of self-awareness, meditation, breathing, exercise, etc.
Biome
Combine that with the biome. The gut microbiome is a multifaceted organ made up of cells that are not your own but which you could not live without. The trillions of guests in your gut that influence your choices, mood and behaviour. Your gut microbiome is, essentially, an outsourced organ.
You are a community
Whether you like it or not, you are teeming with microbial friends. You are the host of between 20 and 40 trillion microorganisms. The community is made up of tens of thousands of species of bacteria, viruses, fungi and other types of microscopic organisms. You have at least as many microbes living with you as there are cells in your body, and probably more. But when it comes down to genetic material, prepare to be completely humbled: 99% of the genetic material you carry around with you is microbial. Almost every surface of the body is covered in microorganisms, but the vast majority of your microbial companions reside along the 9 metres of your gastrointestinal tract.
The microorganism as a puppet master
If you transplant the microbiomes of different types of wild rodents into germ-free mice, you can determine their type of foraging behaviour and what they choose to eat. The microorganism as a puppet master, bending the will of its host for its benefit:
- An addiction to fast food might partly be down to fat- and sugar-loving microbes in your gut making persistent delivery requests.
- By transplanting the microbiomes of younger mice into elderly rodents, his team were able to reverse age-related immune changes in the animals’ brains and improve cognition and ageing-related anxiety.
Programming your biome
The question is whether and how you can program your biome. Food is one way of doing that (hence Ayurveda). Microbiome transplants might one day provide an option for human health treatment—either in the form of enemas or ‘capsules’.
Gut feeling
Humans have always had an instinctive ‘gut feeling’ that our mind and gut are interlinked. And as our gut microbiome is a key element of our gut, an organ in and of itself, it should be no surprise that there are plenty of biological roads linking this microscopic community with the brain. There are four primary pathways between the gut microbiome and the brain: neural (relating to the nervous system), endocrine, metabolic and immune.
Immunoception
The author adds immunoception as a concept. Your brain constantly monitors your immune system, but your immune system is also listening to your thoughts. When your immune system engages a pathogenic invader, your thoughts, mood and behaviours change, along with an increased sensitivity to pain. The question is whether it works the other way. For example, placebo effects and your mindset.
Stress
Stress is like a battle horn to the immune system. In the short term, at least. In this ‘fight, flight or freeze’ response, you become temporarily superhuman. This is total war: your whole defence system is mobilised into action. More simply put, it is a whole-organism reaction. When we realise that every element of our being is fine-tuned to detect and respond to threats, the mind-body debate becomes immaterial. The human organism has not been designed and refined to flourish under the pressures of our modern world. It has adapted to rapidly respond to often-fanged and sometimes furry threats.
Psychology is biology
As a prediction machine, mere expectation—conscious or unconscious—can powerfully change your physiology. Your immune system also preemptively readies itself for battle during a specific mood state. Learning emotional regulation—whether informally or with the help of a clinician—is not simply good for your mental health; it balances your defence system, which benefits all health. We should remember that psychology is biology, and stress is a defence system-wide reaction. It should be no surprise that thoughts can change the state of our immune system. Just as your immune system recruits your mind during an infection, your mind can recruit your immune system during stress.
You are a loop
The environment acts upon you, and you act upon the environment. You are a loop. When your defence system is healthy and balanced, this virtuous circle can bear the load of short-term threats, recalibrating once the danger has passed. Sometimes, the expectations get primed, and you get into a negative feedback loop.
Chronic inflammation
Your psychology and the loop can cause chronic inflammation. Every ‘mental health condition’ is also physical, and every ‘physical health condition’ has a mental element. Chronic inflammation – which can be viewed as the result of an imbalanced defence system – lies at the root of physical illness as much as it does mental. Inflammation in the body – whether from an infectious source or not – can affect the brain. There is plenty of evidence to suggest a correlation between dementias such as Alzheimer’s disease and excessive, long-term inflammation in the body, known as chronic inflammation. Movement enhances immunity.
Advice
The advice is simple: seeds, herbs, spices, grains, vegetables, yoghurt, probiotics and most definitely NOT processed food. Even the suggestion of a psychobiotic diet. Go for a walk. Dance. Exercise. There are many links between movement and cognitive function. Fitness and muscle strength (not necessarily muscle size) are good for mental and physical health: they feed into your brain’s perception of what you can achieve and do. Get a pet (good for your biome). Sleep. Sleep and immunity are also deeply entwined. Love. Be kind to yourself and generous towards others. Connecting with and showing compassion for others is a great way of training and building a healthy defence system on every level.All the usual suspects. Make it a habit.
Consciousness
The best sentence in the book is this one: “All conscious human experience lies in the space between the brain’s model of the world and the actual state of that world.” This brings you to “Metahuman” and “Inner Engineering“.
The biology of belief, indeed.
