Glutathione (TSH) is a tripeptide consisting of the three amino acids cysteine, glycine, and glutamic acid. Glutathione is considered one of the most important antioxidants in the human body.
What is glutathione?
Glutathione is also known as γ-L-glutamyl-L-cysteinylglycine. It is a sulfur-containing tripeptide, so it belongs to the group of proteins. Chemically, glutathione is not a regular tripeptide, since glutamic acid and cysteine are linked via the γ-carboxyl group of glutamic acid. In a true tripeptide, the bond would be formed via the α-carboxyl group. Glutathione occurs in the body as active, reduced glutathione and as oxidized glutathione. Mainly, glutathione serves as a cysteine reserve and as a redox buffer.
Function, effects, and roles
Glutathione is an emergency reserve for cysteine. Cysteine is an amino acid that can normally be formed in the liver in adults. It plays an important role in protein synthesis, the production of proteins. The body produces larger amounts of cysteine itself, but since the amino acid is constantly and irreversibly lost through oxidation, deficiencies can occur. In this case, glutathione can be converted into cysteine. About three grams of cysteine circulate in the blood in the form of glutathione. This supply lasts for three days. Glutathione can also be used for taurine synthesis. Taurine plays a role in the production of bile acids and influences signal transmissions in the central nervous system. Taurine deficiency leads to immune deficiency and disorders in the immune system. Another important task of glutathione is the protection of proteins and membrane lipids against so-called free radicals. Free radicals are formed during numerous metabolic processes that take place under oxygen consumption. External factors such as stress, ozone, UV radiation, food additives and numerous chemicals also produce free radicals in the body. These short-lived molecules can damage the DNA and RNA of cells, proteins and fats. Free radicals play a role in the aging process and in the development of many diseases such as cancer, arteriosclerosis, diabetes mellitus and Alzheimer’s disease. In order to protect cells from free radicals, glutathione is oxidized. In addition, glutathione helps the liver to eliminate harmful and toxic substances. For each harmful molecule to be excreted, glutathione, among others, is required. It weakens the harmful effects of X-rays and chemotherapy. Glutathione can also mitigate the effects of tobacco smoke and alcohol. Glutathione is also used for detoxification in cases of intoxication with heavy metals such as lead, cadmium or mercury. The tripeptide also ensures the physiological course of cell division, cell differentiation and cell metabolism and thus, in the best case, prevents degeneration. Glutathione also performs tasks in the immune system. It is involved in the formation of so-called leukotrienes. These control the white blood cells. Glutathione thus also serves to strengthen the immune system.
Formation, occurrence, properties and optimal values
Actually, almost all cells in the body are capable of producing glutathione. However, the main site of production is the liver. Cysteine, glycine and glutamic acid, adenosine triphosphate (ATP) and magnesium ions are needed for its formation. But glutathione is also found in foods, especially fruits and vegetables. High levels of glutathione are found in watermelons, asparagus, oranges, broccoli, zucchini, spinach or potatoes. Foods that contain limonene are beneficial for the synthesis of an enzyme that contains glutathione. Limonene is found in celery, fennel, soy or wheat. As a rule, the need for glutathione is covered by a balanced diet, provided that it contains sufficient cysteine, glutamic acid, magnesium and selenium. In the body, glutathione occurs in two forms. First, it is present as active, reduced glutathione and second, as oxidized glutathione. In a healthy person, the ratio of active to oxidized glutathione is 400:1. Active glutathione is the effective form. Only in this form is the tripeptide able to render free radicals harmless.
Diseases and disorders
Under normal circumstances, the body is able to produce sufficient glutathione. However, the demand is also quite high.Air and water pollution, prescription drugs, injuries, burns, trauma, heavy metal poisoning, radioactive irradiation, car exhaust, chemical cleaners, and any process that generates free radicals in the body cause increased depletion of glutathione and thus possibly a glutathione deficiency. Actually, it is not a general deficiency of glutathione, but rather a deficiency of reduced active glutathione. To compensate for damage and fight off free radicals, the body uses up the active form. Actually, the enzyme glutathione reductase regenerates the oxidized form and returns it to the active form. However, if the stress in the body from toxins, pollutants and free radicals is too great, the enzyme can no longer completely fulfill its task and more oxidized glutathione remains. The healthy ratio of 400:1 is no longer guaranteed. Under these circumstances, the glutathione redox system can no longer function properly. As a result, the function of the antioxidant defense is also severely impaired. One consequence of this is that the mitochondria in the cells can no longer produce sufficient adenosine triphosphate. ATP is the most important energy store and energy supplier in metabolism and is required for all metabolic processes. Without sufficient ATP, there is an energy deficit. Chronic fatigue is the result. The glutathione level is reduced in many diseases. In biological cancer therapy in particular, glutathione is therefore increasingly prescribed as an adjuvant to chemotherapy and radiation.
