Note: Although liver extract contains many constituents, such as vitamin B12, this monograph focuses on liver extract research.
Liver extract and desiccated (dried) liver have been marketed as iron supplements for over a century. The extract is processed cow or pig liver that may either be a freeze-dried brownish powder or a concentrated liquid that has had most of the fat and cholesterol removed.
Preliminary clinical studies indicate that liver extract may be helpful in treating hepatic (liver) dysfunction. In addition, liver extract seems to work synergistically with interferon in treating hepatitis C and other viral infections. More research is needed in these areas.
Laboratory studies indicate that liver extract may have some effects that could be useful in treating certain forms of cancer, such as the ability to direct migration of metastasizing cells and the inhibition of DNA, RNA, and protein formation. More research is needed in these areas to quantify liver extract's properties.
Some concern has been raised about the safety of liver extract, as it is made of animal liver, which may be infected with parasites, bacteria, or prion diseases. Although there are currently no available reports of diseases such as bovine spongiform encephalitis (BSE, or "mad cow disease") being transmitted by liver extract, the U. S. Food and Drug Administration (FDA) still cautions against the use of any animal organ extract. It is not clear how the processing of liver extract affects the transmission of these organisms.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Ingestion of liver increases red blood cell counts, and liver extract (by mouth or by injection) has the same effect. Both liver and liver extract have high vitamin B12 content. Today, pernicious anemia is typically treated with vitamin B12 injections.
Chronic fatigue syndrome:
An injectable solution of bovine liver extract containing folic acid and cyanocobalamin has been an advocated treatment of chronic fatigue syndrome. Preliminary study indicates that patients with chronic fatigue syndrome positively reacted to intramuscular bovine liver extract. Additional study is needed to make a firm recommendation.
Chronic hepatitis (hepatitis C):
Hepatitis impairs liver function; liver extract has shown liver stimulatory and protective effects. The combination of liver extract and interferon may increase patients' response to interferon therapy alone. However, additional study is needed.
Liver extract seems to stimulate liver function. In two studies, liver extract increased the liver function of patients with impaired liver function. More research is needed to compare liver extract to other hepatostimulatory treatments.
Surgical uses (urological operation adjunct):
Liver extract may help maintain liver function during urological surgery. More research is needed to define the importance of this normalization of liver function.