The liver is the largest organ in the human body and is responsible for well over 200 functions. It is also the most resilient organ, able to withstand the day-to-day modern challenges of air pollution, environmental contaminants, bacteria, fungi, mold, and viruses. In simplest terms, the primary functions of the liver include:
Detoxification – The liver filters 1 liter of blood each minute and eliminates the multitude of common toxins that the body encounters on a daily basis. The liver must dispose of ammonia, a toxic by-product of normal protein metabolism. It converts ammonia to urea, which is excreted through urine. The liver also breaks down environmental chemicals and heavy metals, as well as synthetic pharmaceuticals.
Storage, energy production, and nutrient conversion – The liver is the critical organ for metabolism on all levels. Among its vast array of metabolic tasks, the liver:
- Stores essential vitamins (like vitamins A, B, D, and K), minerals (like iron and copper), and glucose (in the form of glycogen).
- Produces quick bursts of energy when the body needs it most (as part of the body’s “fight or flight” reaction to stress).
- Plays a key role in carbohydrate metabolism, by converting glucose to glycogen. Glycogen is stored as fat in the body.
- Converts vitamins, minerals, and amino acids into their biologically active forms. All nutrients must be “biotransformed” in order to be used by the body. For example, the liver activates B vitamins; converts beta-carotene to bio-available vitamin A; converts iron into ferritin; and converts lysine into active carnitine. Only when the liver is not functioning optimally, can nutrients be converted and properly absorbed by the body. This is why it is important to choose supplements that contain "active forms". (Many supplements on the market contain non-active forms of vitamins that inevitably pass through the body instead of being properly absorbed.) Taking activated supplements eases the task of the liver.*
- Helps to regulate blood sugar levels. When blood sugar is low, the liver uses its store of glycogen, and converts it to glucose (blood sugar). When blood sugar is high, a healthy liver will eliminate excess glucose by converting it to glycogen (stored as fat).
- Regulates protein metabolism. The liver converts essential amino acids so that the body can utilize them.
Immune Response – The liver produces some immune factors (such as fibrinogen) that help the body deal with immune challenges.
Hormonal balance – The liver helps maintain the proper level of hormones, and is a key organ in regulating the hormone insulin (produced by the pancreas) for efficient food metabolism (as mentioned above). The liver converts the thyroid hormone thyroxin (T4) into its more active form (T3).
Digestion and fat regulation – The liver is responsible for the production of bile that aids in the digestion of fats and fat-soluble vitamins. Bile is used to emulsify fats and fat-soluble vitamins (A, D, E, and K) for proper digestive absorption. The liver also removes common naturally occurring fat-soluble toxins from the body by first dissolving them in bile salts, and then excreting them in feces. The liver also controls the production of cholesterol and triglycerides (blood fats).