When we can think about the body as a complex, biological system – a system made up of many smaller, complex subsystems, themselves made up of even smaller systems – then we can begin to develop an approach that targets modern disease for what it is – a non-linear systems problem.
This approach differs from traditional methods of addressing disease, as disease has historically been examined as linear, and as a result, treatments have been created which address disease by breaking it down into individual components and then treating those individual components. This approach is failing us when it comes to approaching modern disease, because modern disease, which arises from a non-linear complex system, needs an approach that reflects this non-linear, complexity.
This new approach would be one that fully incorporates the multi-dimensional complexity that is the human body, which means it would be an approach that uses a broadened perspective to address the system as a whole. A complex, dynamic system cannot simply be broken down, picked apart, and mechanistically determined without losing sight of the big picture – that bigger picture being how the system functions as a whole.
Previously, we reviewed a brief evolutionary history of the human body so that we could put our system into context, creating a good starting place to begin with our approach to addressing modern disease. By understanding the environment in which the human body was designed, we can begin to comprehend the reasons why modern disease has arisen, and begin to conceptualize ideas for how we may fix this problem. By putting the entire system that is the human body into context with the environment it was designed in, we can check off our first step, that first step being an understanding of the broader context of why disease might arise in the human body.
However, simply understanding the context of the human body and its environment does not give us any mechanistic information on how that disease arises. If we are going to effectively address modern disease, then we must have a solid grasp on how disease mechanistically progresses. Therefore, there is a need to understand the actual mechanisms driving the (patho)physiology of the human body, as it is these underlying mechanisms that work together to create the health / disease state of the human body. Thus, in addition to an understanding of the context of the design of the human body, we also need some basic knowledge on how these underlying systems function normally and what happens as they break down.
That understanding of these underlying mechanisms is what we are going to work towards today. By gaining a basic understanding of how a number of underlying systems work together to create disease states, we can start to appreciate the need for a systems approach to tackling modern disease, and additionally, begin to think about what that approach might require.
Getting Started
Moving forward with this new perspective on chronic disease, let us examine the underlying mechanisms driving the progression of these modern diseases. We’ll do this by examining a few of the most prevalent disease-states plaguing the modern world – the diseases that currently affect millions of individuals, and most likely will be the cause of most individuals slow decline into premature morbidity and mortality.
To begin, we’ll start by examining a list of some the most common modern diseases, along with some of the key factors that can contribute to the development of each disease.
1. Atherosclerosis and Cardiovascular disease (CVD)
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- Excess fat circulation
- Inflammation
- Oxidative Stress
- Hyperglycemia
2. Insulin Resistance and Type II Diabetes (IR & TIID)
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- Excess fat circulation
- Inflammation
- Oxidative Stress
3. Obesity
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- Inflammation
- Metabolic Dysfunction
4. Cancer
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- Oxidative Stress
- Metabolic Dysfunction
5. Alzheimer’s Disease (AD)
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- Inflammation
- Hyperglycemia
- Oxidative Stress
Simply by looking at this list, it is pretty easy to see that the most common diseases – the diseases we perceive and treat as isolated cases – are really just different manifestations of the same underlying problems. A body with any combination of systemic inflammation, hyperglycemia, excess fat circulation, and oxidative stress is heading towards a diagnosis of any one these diseases, and quite possibly, more than one.
Please keep in mind, this is a greatly oversimplified list, as it only contains a handful of disease-states and underlying mechanisms. To begin working in more complexity, let’s shift to a slightly different way of looking at these diseases:
Here we have a simple chart with four major diseases and a few of the major underlying mechanisms driving forward the progression of each disease. Looking at the information this way makes it easier to see the same underlying mechanisms driving all these different diseases. While each disease may get its own label because of its unique symptoms, it is pretty simple to see how all the same issues are manifesting in many different forms.
Now, let’s make things more interesting by beginning to think about some of the major symptoms, what we may call outputs, of each disease, and how these outputs feedback to drive each other disease.
For example, while TIID may be driven in part by inflammation and excess fat circulation, it results in more inflammation and fat accumulation, along with hyperglycemia. Of course, this then feeds back to exasperate insulin resistance and TIID, driving the progression of this disease further. Even more, this inflammation, excess fat, and hyperglycemia can then go on to contribute to the progression of other diseases such as CVD and AD.
Let’s add in another layer of complexity with the addition of just one output / symptom of only one disease:
Here, we see hyperglycemia, a symptom of TIID, contributing to the development of other diseases, including AD and CVD. With the addition of this one output, this helps us see how each mechanism is directly intertwined with each other disease, as one symptom quite often ends up being another’s cause.
As we begin to see this dynamic interplay in action, we can see how each underlying mechanism drives any number of disease-states. Moreover, each disease, itself, results in mechanisms that then go on to drive the progression of other diseases.
Adding on one more degree of complexity, we can examine what happens to the entire body with this rise in blood sugar (hyperglycemia). As blood sugar rises, insulin must rise in response, thus pushing the body into a deeper state of energy storage. Can you think of what a deeper state of energy storage may mean?
The answer: More obesity. This means that the above diagram could have an additional set of arrows showing downstream causes of hyperglycemia – downstream causes related to even more fat accumulation, and therefore, more obesity.
As we get into these higher degrees of complexity it becomes difficult to visualize as a chart. As another example, we can examine just one small feedback loop involving inflammation and fat accumulation, in regards to just two diseases:
An obese body is a result of excess fat accumulation, and additionally is caused by systemic inflammation. As the obese condition progresses, more inflammation and fat accumulation ensue. Meanwhile, an insulin resistant state (insulin resistance = a less severe form of TIID) is driven in part by systemic inflammation and excess fat accumulation. Even more, as insulin resistance escalates, this drives more fat accumulation and more inflammation, which of course, results in greater obesity.
Can you see, now, the mess we have on our hands?
My hope, at this point, is that you have begun to comprehend the magnitude of this complex, dynamic interplay. These diseases that we know all-too-well are not really distinct cases, but rather, arise from a complex interplay between a web of underlying mechanisms, these underlying mechanisms all working together to cause any number of disease states.
At this point there is really no need to try to put the entire mechanistic diagram together. I don’t need you to fully comprehend this whole mess; rather, I simply need you to understand that it is quite a mess, and as a result, an approach employing a linear solution, wherein one precise treatment aims to address one precise mechanism – well, that’s just ridiculous.
This brings us back to our overall approach for dealing with modern disease. To effectively address modern disease we need to appreciate the fact that disease arises from disruptions in the interplay between the complex, dynamic systems making up the body. As we have done today, we can work to gain an understanding of some of the major underlying mechanisms driving disease forward.
Meanwhile, we must keep our big picture approach in mind: Disease progression is a non-linear systems problem, and therefore we need to tackle disease as a non-linear system. This does not mean picking apart disease to target specific mechanisms, but rather, thinking critically about how the underlying mechanisms drive disease progression so that we can think of a logical approach to address this entire situation.
At this point we have done the work to help us understand how the body is designed to work, along with gaining an understanding of the key underlying mechanisms driving disease progression. The problem we have, now, is how to put this all together to create an approach to effectively address modern disease.
This may seem like a big problem at first, but it turns out that there is really quite a simple solution. By thinking critically about the design of the human body – how the underlying mechanisms operate and how the body has traditionally functioned well – and tying it together with our knowledge on the mechanisms driving the disrupted functioning, we can then think up a solution.
Up next, we’ll do just that.