The spleen is an organ located under the left side of the rib cage. Its functions in the body include removing “worn out “ red blood cells and supplying certain types of white blood cells (immune cells). For use as a supplement, spleen extracts are made from the spleens of cows, pigs, or other animals.
According to a theory prevalent in some parts of alternative medicine, the consumption of spleen extracts can strengthen the function of an underperforming spleen. On this basis, spleen extracts are sometimes suggested for supporting the immune system. However, there is no meaningful scientific rationale nor scientific evidence to indicate that this approach actually works.
Some manufacturers of glandular products claim that the animal version of an organ provides nutrients that support the corresponding organ in humans. However, there is no evidence that the human spleen requires any nutrients that are uniquely available in animal spleens.
It has been suggested by one manufacturer that consuming extracts of an organ might offer benefit in an indirect manner. According to this theory, some people may possess antibodies to certain of their own organs, and by consuming a similar organ, these antibodies will be diverted from their target. However, this explanation does not make a great deal of sense. Antibodies are primarily produced against proteins, and even if cow spleens had the same proteins as human spleens, which is unlikely, proteins are digested in the intestines and not absorbed whole into the bloodstream.
It may be that, on an unconscious level, those who recommend glandular extracts are being influenced by the ancient notion of “sympathetic magic,” the idea that eating a lion’s heart, for example, will create courage. However, this is a prescientific form of reasoning that is difficult to take seriously in the modern era.
In any case, there is no meaningful scientific evidence to indicate that use of spleen extracts offer any benefits. Only double-blind, placebo-controlled studies can show a treatment effective, and at present none have been reported for spleen extracts. (For information on why this type of study is essential, see
Why Does This Database Rely on Double-blind Studies?) The only published studies on oral use of spleen glandular extracts date back to the 1930s, and do not remotely reach current scientific standards.1-3
More recent studies have evaluated injected extracts of spleen, but these findings are not likely to apply to the oral product.