- Glutathione: what is it, and why should I know about it
- Vitamin C as an antioxidant and helper of glutathione
- Selenium is essential to create enzymes needed in the production of glutathione
- Cystine, the best delivery system of amino acids inside the cell
Nutrients are well known for their individual benefits on the body, but they do not work alone. They interact with each other, creating a greater effect than they would individually. For the production of glutathione, it is important to consume enough of these building blocks simultaneously.
Examples of synergistic nutrients are glutathione, vitamin C, cysteine and selenium. They all work together and need each other to survive and carry out their functions effectively. Let’s break them down…
What is Glutathione?
Glutathione is a powerful antioxidant which is naturally produced by your body. Composed of 3 amino acids: cysteine, glutamate (which forms glutamic acid) and glycine. Through two energy dependent reactions these precursors together produce glutathione.
Glutathione has a number of functions including
- Acting as an antioxidant defense
- Detoxifying metabolic products
- Regulating important cell processes (1)
Over time levels of glutathione become depleted. This is due to the body experiencing infections, toxins and aging. In order to provide the body with a powerful defense, glutathione levels need to be increased and maintained.
Although glutathione is named ‘the mother of all antioxidants,’ the body still requires other nutrients to work with it.
Vitamin C
Vitamin C is a water-soluble vitamin working within the body as an antioxidant. Additionally, it regulates the production of collagen, a structural protein that holds bones, muscles and other tissues together.
Maintaining vitamin C levels is crucial, as it dissolves in water and so cannot be stored within the body. As a result, any vitamin C that isn’t used by the body exits through urine.
For optimum health an adequate intake of vitamin C must be reached daily. Found in fruit and vegetables, the daily intake can be achieved through maintaining a healthy diet. But if you find this difficult vitamin C can be taken as a supplement.
Vitamin C also works synergistically with glutathione and studies have shown that
- Supplements increase glutathione in human white blood cells located in the lymph (2)
- Provides maximal protection of cells that line blood vessels and lymphatic vessels when present with glutathione (3)
- Vitamin C also interacts with Selenium and research has determined that it is
- Involved in the maintenance of selenium homeostasis (4)
Selenium
The trace element Selenium is an important nutrient that the body requires to make many selenoproteins. Selenocysteine is an amino acid that is found in selenoproteins which work within the body to transport lipids and most importantly, reduce oxidative damage to lipids and DNA. Both DNA damage and oxidative damage have been linked to be a cancer risk which selenium in selenoproteins limits. (5)
Selenium also plays a role in the glutathione cycle, a process which recycles glutathione. Glutathione undergoes a redox reaction with the enzyme GPx to detoxify reactive oxygen species which cause oxidative stress to cells. Selenium availability regulates GPx and therefore, regulates the first stage in the process of recycling glutathione. (6)
Cysteine
Cysteine is a sulphur-containing amino acid that is directly used in the production of glutathione in the body. The concentration of cysteine outside cells is normally quite low as it exists in another form called cystine. Cystine is like cysteine as it is a sulphur-containing amino acid however, it is made up of two cysteine molecules bonded together by a disulphide bond. This disulphide bond provides cystine with more stability than cysteine alone. (7)
Research has suggested that cystine can be used as a delivery system of cysteine. As upon digestion it is not used by cells in the gastrointestinal tract or spontaneously broken down in the blood unlike cysteine is. When taken up by cells cystine is immediately reduced back to cysteine. Therefore, it can provide cells with two molecules of cysteine which will overall increase the bioavailability of cysteine in cells. This forward thinking has led to the creation of cysteine supplements in the form of cystine. (8)
Cysteine is important in the body as it is the rate limiting amino acid in the production of glutathione. This means that the reaction will only start when there is a large supply of cysteine available to cells. (9)
By increasing the amount of cysteine inside the cell through cystine supplementation there is more cysteine available to the cell. Supplementation of cystine has shown an increase in glutathione production. (10)
References
- Wu, G., Fang, Y.-Z., Yang, S., Lupton, J. R., & Turner, N. D. (2004). Glutathione metabolism and its implications for health. The Journal of Nutrition, 134(3), 489–492.
- Chowdhury, M. S. (2016). Determination of amount of Vitamin C (Ascorbic Acid) from supplied commercial tablets by using Determination of amount of Vitamin C (Ascorbic Acid) from supplied Drug by using Iodometric titration. (March).
- Montecinos, V., Guzmán, P., Barra, V., Villagrán, M., Muñoz-Montesino, C., Sotomayor, K., … Vera, J. C. (2007). Vitamin C is an essential antioxidant that enhances survival of oxidatively stressed human vascular endothelial cells in the presence of a vast molar excess of glutathione. Journal of Biological Chemistry, 282(21), 15506–15515.
- Watts, D. L. (1988). The nutritional relationships of magnesium. Journal of Orthomolecular Medicine, 3(4), 197–201.
- Puspitasari, I. M., Abdulah, R., Yamazaki, C., Kameo, S., Nakano, T., & Koyama, H. (2014). Updates on clinical studies of selenium supplementation in radiotherapy. Radiation Oncology, 9(1), 1–9.
- Baker, R., Baker, S., LaRosa, K., Whitney, C., & Newburger PE. (1993). Selenium regulation of glutathion peroxidase. Archives of Biochemistry and Biophysics, Vol. 304, pp. 53–57.
- Bridges, C. C., Kekuda, R., Wang, H., Prasad, P. D., Mehta, P., Huang, W., … Ganapathy, V. (2001). Structure, function, and regulation of human cystine/glutamate transporter in retinal pigment epithelial cells. Investigative Ophthalmology and Visual Science, 42(1), 47–54.
- Winter, A. N., Ross, E. K., Daliparthi, V., Sumner, W. A., Kirchhof, D. M., Manning, E., Linseman, D. A. (2017). A Cystine-Rich Whey Supplement (Immunocal®) Provides Neuroprotection from Diverse Oxidative Stress-Inducing Agents In Vitro by Preserving Cellular Glutathione. Oxidative Medicine and Cellular Longevity, 2017, 1–15.
- Richman, G. (1974). Regulation Feedback of y-Glutamyl-Cysteine Synthetase Inhibition by Glutathione * bv Nonallosteric. 250(4), 1422–1426.
- Winter, A. N., Ross, E. K., Daliparthi, V., Sumner, W. A., Kirchhof, D. M., Manning, E., … Linseman, D. A. (2017). A Cystine-Rich Whey Supplement (Immunocal®) Provides Neuroprotection from Diverse Oxidative Stress-Inducing Agents In Vitro by Preserving Cellular Glutathione. Oxidative Medicine and Cellular Longevity, 2017, 3103272.
