I like to think of the liver as the body’s primary bodily component in charge of maintaining metabolic homeostasis. It is continuously sensing the energetic supply and demand of the body and performing the task that is converting energy forms based on what is present and what is lacking.
How does it work?
The liver takes in energy and signaling molecules that are present in the circulation. Because of the liver’s close proximity to the digestive tract, it takes in the blood that has received the load of nutrients that were recently digested. The liver takes in this recent load, combined with the load that has been out in circulation. For example, it is taking in blood containing signaling molecules from other bodily components, including the pancreas or adipose tissue.
The liver takes in this energy and these signaling molecules, with which it makes decisions as to what to do with this energy.
For example, the liver may take in carbohydrate and:
- store it as glycogen or
- convert it to fat and ship it out into circulation
Or, the liver may sense that blood sugar is low and break down glycogen into glucose, releasing it into circulation.
These are all healthy processes and are essential for maintaining a well-functioning body. When functioning as it has been designed, the liver maintains a stable supply of energy to the body. For example, the liver keeps blood sugar within a tight range by releasing glucose from stored glycogen (or from protein) when blood sugar levels drop, or by storing glucose as glycogen or converting glucose to fat when blood sugar levels elevate.
But, what happens if the liver becomes incapable of performing these functions effectively?
Liver Dysfunction
As the liver’s job is to help maintain a state of metabolic homeostasis for the entire body, if the liver is incapable of performing its job well, the entire body is negatively impacted. For example, blood sugar will become unstable, ranging from irritating low-blood sugar (leaving you with low energy), or even to life-threatening situations.
A primary mechanism underlying liver dysfunction is fatty liver and insulin resistance. Note that these two are intricately tied together. Let’s explore what drives this state and what it means for the entire body.
Let’s begin with insulin. The elevation of insulin servers as two types of signals:
- a pro-energy storage signal (for instance, adipose tissue will respond to the insulin signal by taking in lipids and sugars and storing it all as fat).
- a signal that blood sugar is elevated (for instance, muscle tissue will stop taking in lipids and oxidizing them as a fuel source so it can instead utilize glucose as a fuel source).
The liver receives this insulin signal and responds with actions that lower blood sugar:
- store glucose as glycogen
- convert excess glucose to fat to be shipped out into circulation
If the liver is insulin resistant it cannot understand the signal that it needs to lower blood sugar. The result? Blood sugar remains elevated.
- If blood sugar is elevated in moderate amounts for long periods of time, the high concentration of sugar in the blood will cause damage to tissues and biomolecules throughout the body.
- If blood sugar is elevated too high, the body is put in a life-threatening situation.
Clearly, it’s important that the liver maintains healthy functioning so that it can keep tight control over blood sugar levels.
Unfortunately, this isn’t the case for far too many modern human beings. Let’s aim to fix this.
What causes a fatty liver?
There are a number of mechanisms that play a role in the accumulation of fat in the liver and its path to insulin resistance. Instead of diving into specific mechanisms (let’s not overwhelm ourselves here with the details), let’s think about the general pattern that drives this unhealthy state: fatty liver and insulin resistance arises as the liver becomes overloaded with energy.
Note one thing here: I did not say that it is fat, specifically, that drives the accumulation of fat in the liver. Fatty liver arises as the liver is overloaded with energy of any kind: lipids, sugars, and proteins.
Remember, part of the liver’s functioning is to take sugars and convert these to fat to be shipped out into circulation along with other lipids. However, if the liver is taking in too much at a time, this assembly line can get held up. If this energy is held up, where does it go?
Into storage in the liver!
If too much energy is coming in and not enough energy is shipping out such that fat is accumulating, then the liver needs to take action. What does it do?
We know this answer already – it becomes insulin resistant, which means it will stop listening to the insulin signal and blood sugar concentration will elevate.
To understand this response more fully, recall how the liver interprets the insulin signal: insulin serves as a signal that blood sugar is elevated. The liver responds by acting to lower blood sugar:
- this involves storing glucose as glycogen if there is still room to do so (the liver has a finite space for glycogen storage)
- this involves converting sugar to fat to be shipped out into circulation
If, however, the liver, itself, is facing a problem that involves the accumulation of too much fat, it’s going to want to shift its attention to managing it, regardless of whether or not blood sugar is elevated. This is why it becomes insulin resistant – so that it can stop listening to the insulin signal to focus on glucose and it can instead focus on managing fat.
How can we take action to avoid fatty liver and insulin resistance?
Based on this brief introduction to energy flow through the liver, there are a few key ideas that we can walk away with so that we can make healthier decisions.
Most significantly, here we see that fatty liver and insulin resistance develop as an abundance of energy flows through the system. But before we go making any decisions that aim to directly lower energy in the bloodstream (eating fewer calories, as the common logic goes), let’s take a moment to think about if this is really the best course of action.
As we think this through, remember, this is only one piece of the larger picture that is a complex network of cells, tissues, and organs that work as a system. Could it be that the abundance of energy flowing into the liver is actually a downstream effect of energy dysregulation or metabolic dysfunction elsewhere in the body?
To piece together an answer, it helps to take a step back and think about the big picture that is the functioning of each tissue and organ involved in metabolic homeostasis.
To help you out with this process, feel free to head to this page where you can find more information regarding the many different factors at play.
And remember, you always have the ability to take action aligned with what supports the functioning of the body, overall, as determined by how the body evolved to function. That is, you can choose to focus on these 3 key practices:
- Eat real, whole foods
- Move your body regularly and dynamically
- Practice a balance of stress and rest
As you move forward with your journey to better health, keep taking time to piece together your own understanding of the complex network that supports your body. As you do, you’ll gain the ability to refine your decision-making skills so that you can make decisions that are best for your own body.