What is health to you? What is disease? I used to think that health was the absence of disease. I used to think that disease was some kind of enemy out there that attacked me in some arbitary way. So I thought nothing of my health until I was ill and then went immediately to the doctors who knew enough to fix me.
If we think like this, then we are indeed helpless. In this short series I have been looking at what health and what disease is. (Part 1 - Part 2 - Part 3)
Let's sum up today. Let's see the deep evolutionary patterns behind health and disease and so learn enough to be able to make changes to give us the best possible chance of being healthy all the time.
Health
Health is our natural state.
We are designed to be healthy so long as we live inside the evolutionary physical and social environmental norms that have shaped our development.
The further we stray from these environmental norms, the more likely we will get ill.
The longer we live in novel conditions, the more likely we will develop chronic illness.
What is Disease?
Disease itself has an evolutionary trajectory and so it too has ideal and less ideal trajectories and environments.
Disease does well it lives inside its ideal trajectory. Disease does less well when it does not have an ideal environment.
Because all diseases are environmental, they become a problem when we offer them the ideal environment and they go away when this environment is removed or altered.
Infectious Disease
Most infectious disease did not exist in most pre agricultural societies. It arose because of major changes in human culture directly linked with the adoption of agriculture.
These shifts include settling in one place, living close to animals where pathogens mutate across species, using irrigation and so giving mosquitoes a large breeding potential, eating a restricted and grain based diet and living in larger population groupings with a steep social hierarchy with low status and low control at the bottom.
Each infectious disease has a unique pathogen. Each pathogen has its own ideal environment. Most of these ideal environments are linked to the processes of agriculture or its social effects such as population concentration.
Examples include. Malaria and Yellow fever use the mosquito as a vector. Irrigated agriculture and large local host populations offer an ideal environment for an epidemic of malaria or any disease that is water born. Cholera and Typhoid use water as a vector. Poor water systems poor sewage disposal and large concentrated host populations offer the opportunity for an epidemic. TB relies on an air vector. Poor immune systems and overcrowded host populations provide the ideal environment.
Most infectious disease has been reduced by shifts in these environments such as installing sewage treatment and clean water, destroying mosquito breeding sites, better diets and living conditions and by the process of generational immunity as it relates to infectious disease.
Some infectious diseases, such as measles, seek a long term equilibrium with the host. Extreme lethality before breeding has a powerful evolutionary effect on the host. Over 3-6 generations real population immunity is granted. We see this in bacteria themselves and the use of antibiotics. The survivor bacteria have used evolution to make the shift to enable them to combat the antibiotic. We do this too.
Being based on a distinct pathogen, most infectious disease can be controlled by a vaccine, but most of the great infectious diseases had become non lethal in the west by 1900, well before vaccines.
Shifts in the environment made by making changes in the larger culture have been the most cost effective response.
Chronic Illness
Chronic illness is tied to the shift in human culture from the agricultural to the industrial world. It arose because of further major changes in human culture related to the adoption of industrialization and globalization.
Chronic illness is very different from infectious disease. Chronic illness has no distinct external pathogen. But it has everything to do with bacteria.
Evidence is building that the central mechanism for all chronic illness is to be found in the massive colony of bacteria that inhabits the human gut. Our knowledge of this is very new. Up to 90% of a human being is made up of bacteria. It appears that when we think of who we are, we have a new partner.
If this colony is disrupted it will produce toxins. Over time, these toxins will penetrate the gut wall and enter the larger system. This invasion can overwhelm the immune system and drive it to work against the host. The resulting inflammation then affects different people in different ways. Evidence is emerging that heart disease is driven by this inflammation. Most chronic illness can be connected to this inflammation and to the autoimmune later response.
Other evidence is also building for the additional mechanism that is rooted in the metabolic system. The insulin and fat pathways can be disrupted by too much sugar. Some connections are being made here to Alzheimer’s. The mind and the gut seem to have a powerful connection that was unknown to us only a few years ago.
Diet appears to be the single most significant variable in both inflammation and in metabolic syndrome. Changes in diet appear to have the most significant effect on the development of chronic illness and also in its “cure”. Diet is likely to be the core vector for working on the epidemic of chronic illness.
But all of this is complex. While diet and the gut and metabolic system are at the core, other factors interact and iterate and so make things better or worse. These include low levels of physical activity, very disrupted sleep and a highly separated social life with tiny family units, separation from work and life, large impersonal social structures, low personal control and high demand from people in authority that do not share the lives and risks of those that they control.
Our ancestry also plays a factor in these differences. So does our epigenome that is very sensitive to environment.
So, while each illness seems distinct and is located in a part of the body or mind, they are all are related to the same process of failure of the metabolic or immune system.
We don’t know all the details of how all of this interacts and works. But we know enough today, as John Snow did, to know where to work. For the results are clear. People who take action while using these principles get well.
But there is another dimension that we know affects outcomes. We need to know more about that too.
Stress - the multiplier
Some people get flu and then pneumonia and then die. Others get the same strain of flu and recover. Men at the bottom of an an organizational hierarchy are 4 times more likely to die of heart disease then men at the top. 14 out of 15 men with a prostate cancer diagnosis will not die quickly from the disease. No matter what the treatment, that one person will die. There has to be something about the immune system at play here too.
The variable here is stress.
Humans are the most stressed of all animals. Stress acts as a multiplier for the impact and lethality of disease. It does this because its core hormone, cortisol weakens the total immune system.
For most animals, stress is an effective discrete response to a threat. The zebra only goes into the stress response when the lions are hunting. When the hunt is over, the stress response stops and the zebras natural equilibrium returns. For primates, it’s different. We use the value of social units to feed and defend us. Like all species who use social groups, we have very complex interactions that go on all the time. The result is social stress.
All primates, including humans, have developed an evolutionary response to this social stress problem that limits the amount of stress to bearable limits most of the time.
They do this by living in social groups that are large enough to offer a defence and a breeding pool but small enough for all to have a social place and to know everyone.
They also use a core social and physical process, grooming, to keep stress levels down. This is so important that infant primates will choose touch over food.
Because humans are conscious, we stress even more. We can worry about world peace, a dress, what someone said, our boss. We can fill our minds with worry both conscious and unconsciously. Our mind and our ego can set up deep channels of response to triggers that get deeper over time. Consciousness comes with a price.
So why does social stress have such a large impact on our immune system and so on our health outcomes?
The fight or fight response shuts down many parts of the body to give us every chance of out running trouble. This is no problem if we face an immediate and real threat. But if we stress for long times, or all the time, then this is very disabling. Prolonged stress weakens the immune system.
Industrial culture has caused most humans to abandon the social structures that help them, as a primate, find relief. The extended family is disappearing. Also, our social and work structures tend to be transitory and impersonal today. They also tend to be too large. Most people have low status and no say at work.
Industrial culture has also taken away our time and so it has taken away trust. Most of our relationships have become transactional. “Grooming” is not longer possible. In human terms for adults, “Grooming” is mainly achieved by having the time to hang out with close friends and shoot the breeze. You have to do this with people that you trust. We can still see older men do this in Italian neighbourhoods. In human infants, it means “Grooming’! Babies need to be touched all the time. Babies need to be surrounded by people that they trust.
Quality time is not enough. We need lots of free time with others to develop trust and so be able to groom. Babies need lots of time with their parents to be attached, to trust and to be touched.
So, with this as a context, how can we live differetly today when all the forces of our culture drive us away from the ideal path for our health?
More tomorrow. And you can see the whole picture as I understand it here in my short book .
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