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What exactly is glutathione?
- Glutathione is a tripeptide made up of the three amino acids glutamic acid, cysteine, and glycine.
- It comes in Two states exist, which are transformed into one another:
- Reduced glutathione (GSH)
- Oxidized glutathione disulfide (GSSG) (2 hours away)
- From a food law perspective, this is a "functional food protein" (not an amino acid, therefore no restrictions on use)
- Glutathione can be synthesized and recycled by humans, but various building blocks are essential.
- Prerequisite for glutathione synthesis and recycling
- Amino acids (L-glutamate, L-cysteine, L-glycine as well as precursor methionine and possibly N-acetylcysteine) à high dependence on cysteine availability!
- Enzymes (Ɣ-Glutamyl transpeptidase, peptidase, Ɣ-Glutamyl cyclotransferase, Ɣ-Glutamyl cysteine synthetase, GSH synthetase) à high dependence on the activity of Ɣ-glutamyl cysteine synthetase
- Cofactors, which support synthesis and recycling (α-lipoic acid, vitamin C, vitamin E, vitamin B2, vitamin B3, magnesium)
- energy and functional mitochondria (including cofactors such as coenzyme Q10, L-carnitine, vitamins B1, B2 and B3) à GSH synthesis is ATP-dependent
Bioavailability of oral glutathione
- The digestive tract absorbs GSH and other substances. Nutritionally beneficial peptides intact on (e.g., casomorphins, proteases)
- Active transport through intestinal membranes or intestinal epithelial cells has been demonstrated (with partial degradation to amino acids intracellularly).
- Probably also absorption as Glu-Cys dipeptide and resynthesis of the tripeptide (in the liver)
- GSH supplementation improves GSH status more than equivalent amounts of individual amino acids.
- GSH performs functions in the intestine as well as extracellularly and in various cell compartments within the organism.
- Healthy intestinal mucosa is important for the absorption of di-/tripeptides.
- Reasons why no increase in plasma GSH could be detected in some authors after oral administration of GSH:
- Short GSH half-life
- At low GSH concentration and poor redox status, there is no increase in GSH.
(high GSH consumption for regeneration of other redox systems, such as e.g.Ascorbic acid
Effects of glutathione
Antioxidant effects
- Non-enzymatic antioxidant
- Most important hydrophilic antioxidant of the cell (directly binds radicals and nitric oxide (NO) and reduces other antioxidants)
- is oxidized to GSSG (and reduced again with the help of the enzyme glutathione reductase)
- Coenzyme for enzymatic glutathione peroxidases (metalloenzymes)
- (reduce toxic peroxides such as hydrogen peroxide and lipid hydroperoxides by reacting with glutathione)
- Enzymes are proteins (they require amino acids, zinc, vitamin B6 and B12)
- Enzymes require activators (selenium, zinc, manganese)
- (reduce toxic peroxides such as hydrogen peroxide and lipid hydroperoxides by reacting with glutathione)
Regeneration of antioxidants
Inactivation of activated oxygen
Detoxifying effects of GSH
- Glutathione in detoxification phase I
- Disposal of radical metabolites (Part of the redox network)
- Glutathione in detoxification phases II and III
- Coenzyme for glutathione S-transferases
- Binding partners of pollutants
- begins via thiol/sulfhydryl/SH group Toxins, polyvalent heavy metals such as mercury, cadmium, lead and other foreign substances
- forms Pollutant-glutathione complexes, which are excreted as mercapturic acid derivatives via the kidneys and bile
- reduces by Complex formation with "good" trace elements pro-oxidative risk of high concentrations of these substances (z.B(Fenton reaction of iron with vitamin C)
- Note: GSH can be combined with other chelating agents such as α-lipoic acid.
Glutathione and Detoxification Phase II
Causes of glutathione deficiency and possible consequences
- causes
- Low intake (z.B. Nutrition, malabsorption disorders)
- High demand (z.B(e.g., free radical exposure, pollution, illness, lifestyle mistakes, age, stress, exercise)
- Disorders of glutathione synthesis and metabolism (z.B.Deficiency of amino acids, glutathione reductase or glutathione peroxidase)
- Follow
- Oxidative and nitrosative (NO) stress
- Energy shortage
- Thiol group deficit (-SH)
- Detoxification disorders
- Immunosuppression and susceptibility to infection
- Reperfusion injury, increased hemolysis rates
- neurological, psychomotor, cardiovascular, ocular and hepatic disorders
Glutathione diagnostics
- Nutritional and lifestyle history
- Specific symptoms
- Laboratory test
- Total glutathione (erythrocytes): 1805-3600 μmol/l
- GSH reduced (leukocytes or erythrocytes): 962-3329 μmol/l
- GSH:GSSG ratio (serum): 99:1 to 90:10 (no information about the intracellular situation)
- Glutathione peroxidase: 4170-10880 U/L
- In cases of stress/illness, the GSH/GSSG ratio shifts first.
- Long-term decrease in total glutathione
Glutathione requirements
- The exact glutathione requirement in addition to diet and endogenous synthesis is not precisely known and depends on many factors (intake, synthesis, individual situation).
- In cases of stress/illness, the GSH/GSSG ratio shifts first.
- Long-term decrease in total glutathione
- Disruptions only become apparent when GSH stock &< 1 g (so there is already a shortfall of approximately 7 g compared to the "normal stock")
- Furthermore, due to ongoing strain, the demand for GSH remains high.
Typical glutathione dosage
| substance | Dosage (oral, per day) | Parenteral dosage (per day) |
| Glutathione prevention (in case of risk) | 0.2 – 1 g | - |
| Initial glutathione therapy | 1-5 g | 400-600 mg |
| Glutathione follow-up (after therapy) | 0.6-1.2 g | - |
- Oral bioavailability is guaranteed!
(z.B. Richie JP et al.; Randomized controlled trial of oral glutathione supplementation on
body stores of glutathione; European Journal of Nutrition 2014)
Glutathione content of foods (Source: Reuss F)
| Groceries | GSH mg/kg |
| Brewer's yeast extract (fresh) | 10000 (Reiff, 1960) |