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Abstract
The primary role of glutathione is to protect cells from oxidative stress. It is abundantly distributed in the mucosal cells of gastrointestinal tract both in animals and man. The highest concentration is found in the duodenum. The amount of glutathione ingested with foods, age and drug or ethanol consumption affect glutathione concentration. The detoxifying capability of glutathione is directly related to its thiol group and to its function as a substrate for enzymatic activity; in fact, glutathione regulates the action of glutathione-peroxidases and glutathione-transferases.
Glutathione is a tripeptide composed of glycine, cysteine and glutamine amino acids. These three amino acids are abundant in meat and poultry products and staple food such as rice. Cells in the body produce high amounts of glutathione, indicating that this molecule has a crucial role in the body. It is as important as cholesterol, glucose and potassium since all have similar levels in the cells. As a powerful antioxidant, it scavenges excess free radicals produced during cellular metabolism and chemical reactions. It neutralises these harmful free radicals, toxins and certain metals such as mercury . Glutathione exists in two forms: reduced glutathione (GSH), the active form of the tripeptide, and oxidised glutathione, the inactive state. Free radicals are not ordinarily harmful when produced in appropriate amounts. However, when found in excess, they can cause cellular damage and even cell death.
Glutathione reductase enzyme converts oxidised glutathione (the inactive form) to reduced glutathione. As long as glutathione reductase can cope with the conversion of oxidised GSH to reduced GSH, there will be no problem in neutralising free radicals.
However, the problem lies when glutathione reductase is overwhelmed. When this occurs, levels of GSH become depleted, leading to an increased number of free radicals in the body. Since there is not enough reduced GSH to neutralise the free radicals, these radicals accumulate and can cause cellular damage. When low levels of GSH are prolonged, this can lead to constant cellular damage, leading to different diseases.
When a person ages, the number of GSH produced also reduces. This would explain why older people are more prone to diseases caused by chronic inflammation. Some of these diseases include GIT, type 2 diabetes, cardiovascular diseases and certain forms of cancer.