What Does the Liver Do?
The liver is located on the right side of the body, in the upper abdomen. In humans, it is the second largest organ of the body, weighing about 4 pounds (lbs.) (skin is the largest organ). Even while exposed to tremendous potential for damage, the liver performs a multitude of essential functions: metabolizing, detoxifying, and regenerating. It does an extraordinary job of keeping us alive and healthy by metabolizing the food we eat (ie, breaking it down into useful parts) and protecting us from the damaging effects of numerous toxic compounds we are exposed to on a daily basis. Several times each day, our entire blood supply passes through the liver. At any given time, about a pint of blood is in the liver (or 10% of the total blood volume of an adult) (NIDDK 2000). In addition, the liver has impressive restorative capabilities and is the only organ in the body capable of regenerating itself when part of it has been damaged.
The metabolizing functions of the liver are numerous. The liver is intricately involved in carbohydrate, fat, and protein metabolism; the storage of vitamins and minerals; and in many essential physiological processes. The liver is also involved in several regulatory mechanisms that control blood sugar and hormone levels. It synthesizes proteins (eg, plasma albumin, fibrinogen, and most globulins), lipids and lipoproteins (phospholipids, cholesterol), as well as bile acids that are excreted in the detoxification process (NIDDK 2000).
Other important functions of the liver include production of prothrombin and fibrinogen (two blood-clotting factors) and heparin (a mucopolysaccharide sulfuric acid ester that helps prevent blood from clotting within the circulatory system). The liver also processes glucose into glycogen and stores it until muscles need energy; when released, glycogen becomes glucose in the bloodstream. Some glucose is also converted and stored as fat.
Additionally, the liver produces and secretes bile (stored in the gallbladder) that is needed to break down and digest fatty acids, and produces blood protein and hundreds of enzymes needed for digestion and other bodily functions. As the liver breaks down proteins, it produces urea, which it synthesizes from carbon dioxide and ammonia. Urea is the primary solid component of urine, and it is eventually excreted by the kidneys. Essential trace elements such as iron and copper as well as vitamins A, D, and B12 are also stored in the liver.
The detoxifying function is an essential part of human body metabolism, with the liver playing a key role in the process. Toxic chemicals, of internal and external origin, constantly bombard the liver. Even normal everyday metabolic processes produce a wide range of toxins neutralized in the liver.
The regenerating capacity of the liver is one of the most intriguing survival mechanisms of the body. The liver is an incredibly resilient organ. Up to 75% of its cells can be surgically removed or destroyed by disease before it ceases to function (AMA 1989). As with some other organs, the liver has been designed with an excess of tissue to protect it from damage or loss of function. The healthy parts of the liver have an amazing capacity to regenerate new, healthy liver tissue to replace damaged liver tissue.