The liver is the Grand Central Station of our metabolism, handling an enormous amount of molecular traffic. The liver is the site of a huge variety of processing, whose vital roles include:
Breaking down nutrients
Filtering out toxins that come in from the gut and breaking them down
Synthesizing important blood components
There are extensive networks of tiny blood vessels around the gut that absorb nutrients from our food. This nutrient-rich blood all flows directly into the larger collecting veins of the portal system and is carried on to the liver. Another network of capillaries comprises the bulk of the liver and surrounds the liver cells. Guarding this system are specialized cells called macrophages, which destroy much of the bacteria that comes in from the GI tract.
All the nutrients and other substances that have been absorbed from our food are processed by the liver and then transported to the rest of the body. Nutrients will be broken down to provide energy and the raw materials from which our body will actually be constructed and maintained. These are the building blocks of muscle, skin, and bone.
The liver also functions somewhat like the oil filter on your car; one of its jobs is to protect the rest of the body from all the debris and gunk that could be harmful. Essentially all the material absorbed from the gut passes through the liver, carried by the bloodstream. The liver cleans the blood before it enters the heart and before it’s pumped throughout the body.
So the liver is the center for toxic cleanup in the body. The majority of the toxins are processed and transformed there. Some substances are exiled: If they don’t measure up, they may get processed out of the body via the bile, in the urine, or in stool. If the liver is required to process too many toxins, an overload may occur. Then the impaired capacity can limit its ability to monitor incoming traffic and filter out harmful substances, like a police force outnumbered by thugs who then get into general circulation.