What is Selenomethionine?

Selenomethionine is an amino acid that contains the element selenium. It is also known as Se-met or Se. This acid is not produced in the human body naturally and must be ingested. Only small amounts of selenium are required for the body to function properly. According to the Institute of Medicine of the National Academy of Sciences (IOM), the recommended daily dosage of selenomethionine is 45 micrograms (ug) for a baby and 400 ug for an adult.

This amino acid is necessary for the protection of red blood cells, and their membranes, from reactive agents. It operates as an antioxidant, which can shut down these agents before they attack red blood cells. It becomes active by bonding to proteins in place of methionine. Methionine and selenomethionine are bonded interchangeably by proteins, and both are beneficial. Selenomethionine may also have an anti-aging effect.

Selenium is found naturally in many plants, including wheat, soybeans, and Brazil nuts. These sources are usually enough to maintain a healthy level of selenium in the body. Typically, this amino acid is self-regulating in the human body. This means it is stored in proteins until enough has been accumulated, and then bonding of selenomethionine stops.

A deficiency in selenium can lead to reduced immune system cell production, and a higher risk of death in patients with human immunodeficiency virus (HIV). Also, a lack of selenomethionine can impair thyroid function. Too little selenium can also inhibit the production of glutathione peroxidase, another of the body's main antioxidant agents.

An excess of selenium can also have damaging effects on the body's function. Selenium toxicity can cause a loss of hair, fatigue, and white fingernails. In horses, too much of this amino acid causes Alkali disease, resulting in deformed hooves, hair loss, and weight loss.

Another form of selenium that can be ingested by humans is selenite. Selenite is an inorganic chemical compound, whereas all forms of selenomethionine are organic. A recent clinical study showed that organic selenium was absorbed at a rate 19% better than its inorganic counterpart.

In 2009, a study was conducted to determine the usefulness of selenomethionine as a cancer treatment. A group of prostate cancer patients were used, and it was determined that the both Se-met and selenium were present throughout their prostate cells. This has given researchers hope that selenium may be effective as a chemo-preventive agent for prostate cancer.