The Antioxidant Power of Glutathione
By Karen E. Todd, R.D.
Reprinted from Natural Products Marketplace.
Nutrition scientists and many physicians have known for years that glutathione, a small protein composed of cysteine, glutamic acid and glycine, is one of the most important protective molecules in the body. Glutathione can be made by all cells and is also provided by fresh foods in the diet. What has not been known until recently is glutathione levels in tissues and body fluids can be enhanced with oral supplementation.
"Glutathione has been the best kept secret in biochemistry and nutrition, despite the fact that it is found in every living cell in every living organism," said John Richie, Ph.D., a glutathione researcher and professor of Public Health Sciences and Pharmacology at Penn State University College of Medicine. "It plays many important roles in metabolism, but is perhaps best known as the major detoxification compound in all living organisms."
Among its protective roles are eliminating toxic chemicals; maintaining cell proteins; supporting immune function; regenerating vitamins C and E; and regulating cellular processes, including cell differentiation, proliferation and apoptosis.
Imbalances or deficits of glutathione generally increase susceptibility to oxidative stress and a host of related diseases. Low glutathione status has been associated with many aging and chronic conditions. 1 Conversely, high glutathione levels have been correlated with better health in old age as measured by number of illnesses, blood cholesterol, blood pressure, body weight, and general physical and mental health. 2,3
The potential health benefit of raising glutathione status seems self-evident; yet, clinical research with glutathione in human health has been sluggish compared to other nutrients due to lack of understanding about the fate of oral glutathione.
"People have assumed oral glutathione would be degraded in the gut and would not be bioavailable, but research during the past 30 years has established that clearly is not the case," Richie said. "Oral glutathione is available to the body via three routes: it can be absorbed intact in the intestines and taken up by tissues; it can be broken down in the gastrointestinal (GI) tract to its constituent amino acids, which are then absorbed by tissues and recombined to make glutathione; and it can be taken up directly by mucosal cells of the GI tract." 4,5,6,7,8,9,10
Studies have provided detailed evidence for specific glutathione transport in the intestines, lung and kidneys. 11 In addition, according to Dean P. Jones, Ph.D., a glutathione expert at the Emory University School of Medicine, exogenous glutathione would support detoxification of harmful inhaled and ingested substances even if it were not absorbed. "The presence of glutathione in extracellular fluids suggests a universal role in protecting cell surfaces," Jones said. "A high concentration of glutathione is maintained in lung epithelial lining fluid to eliminate airborne oxidants and help maintain fluidity of the mucus lining the airways. In our lab, we have also shown glutathione in the mucus lining of the gut provides a detoxifying barrier in the small intestines." 12
Dietary intakes of glutathione in the United States span a wide range from as low as 3 mg/d to as high as 250 mg/d. 13,14 Diets that provide the most glutathione are high in fresh fruits, vegetables and meats. In contrast, diets consisting largely of processed foods provide very little glutathione. Most people obtain only about 50 to 60 mg/d via the diet.
Many factors compromise glutathione status, including advancing age, exposure to tobacco smoke or other pollutants, exposure to radiation, use of multiple medications, including over-the-counter (OTC) drugs, alcohol intake, obesity, type 2 diabetes and other chronic diseases. 15 Thus, it is likely there is a considerable gap between the body’s need for glutathione and the usual daily supply.
"When people gain an understanding of the central role glutathione plays in their health, and the fact that they can have control over the levels of glutathione in their body, I think we will see a dramatic increase in demand for glutathione supplements, particularly among the Baby Boomer population," Richie said.
Karen E. Todd, R.D. is director of marketing with Kyowa Hakko USA, which produces the branded ingredient Setria® Glutathione, a pure and natural source of reduced glutathione.
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