Glutathione is one of the major sulfur-containing compounds in the human body. L-glutathione is a powerful antioxidant; it is necessary for carbohydrate metabolism; it has anti-aging properties and breaks down oxidized fats. Glutathione is found in high concentrations in the lens of the eye. While there is still some debate about the intestinal absorption of oral glutathione, serum levels of glutathione can be increased by the ingestion of N-acetyl cysteine (NAC).
Glutathione is found as a stereoisomer and should be in the 'L' configuration (L-glutathione). It is listed in the U.S.P. and can be purchased as such.
Supplementation with reduced glutathione does not necessarily raise tissue levels of glutathione, and it can be expensive. While the unreduced form is much cheaper, it is not metabolically active. Doctors often report that clinical benefits achieved with intravenous reduced glutathione are not seen when it is taken orally. Riboflavin and niacinamide are essential cofactors for generating reduced glutathione.
Common toxins that glutathione may help protect against are car exhaust, cigarette smoke, heavy metals, aspirin and alcohol, as well as many pesticides and industrial chemicals.
Increased levels of glutathione have been shown to slow the progression of cataracts.
One of the body's normal mechanisms for dealing with heavy metals involves glutathione and normal levels of this protein should thus be ensured. The rate-limiting precursors are the amino acids cysteine (or N-acetyl-cysteine) and glutamine.
Glutathione can cross the blood-brain barrier; it can remove mercury, cadmium and other toxic metals from the brain.
Glutathione levels in antigen-presenting cells determine whether Th1 or Th2 response patterns predominate [Proc Natl Acad Sci USA 1998 Mar 17;95(6): pp.3071-6]. Increasing glutathione levels helps reduce a Th2 dominance.
Researchers have found that age-related macular degeneration correlates with low glutathione levels. When taking into consideration other variables such as smoking, age, cardiovascular disease and multivitamin use, depletion of glutathione by itself was thought to be a major contributing factor behind macular degeneration. [British Journal of Ophthalmology, 1994; 78 , pp.791-4)]
Since the discovery more than a decade ago that Parkinson's patients suffer from a profound deficiency of the powerful brain antioxidant glutathione, medical researchers have been actively exploring techniques to administer this naturally-occurring chemical. It is currently used intravenously.