Glutathione and sports nutrition

Exercise plays an important part in keeping us healthy. But it is not without its pitfalls. As exercise intensity increases, our rate of respiration also increases and, in turn, so does the production of free radicals or reactive oxygen species (ROS). This can lead to what is commonly referred to as oxidative stress which can damage our cells and tissues.

Ordinarily, the glutathione produced in our cells is a very effective ROS scavenger, neutralizing free radicals, such as the highly toxic superoxide and hydrogen peroxide before they can cause havoc. But during high intensity or endurance exercise, our cells may not have the capacity to keep up with the demand for glutathione. This results in a glutathione deficit where our body is unable to neutralize all of the ROS produced. We have all experienced this situation: Lack of energy, fatigue, listlessness and that ‘run down’ feeling, which is a common symptom of glutathione depletion following exercise.

Sport scientists have long advocated the use of antioxidants to combat exercise related oxidative stress ^[1]. Glutathione (GSH), being the ‘Master Antioxidant’ is the obvious choice. Not only does it have a profound effect on neutralizing ROS, but it also recycles Vitamin C which is also another important player in the recovery phase. Many sports supplements, however, only address the issue of protein/energy deficit and electrolyte loss during the recovery period, but this is only part of the problem. Whilst protein and electrolytes are easily and rapidly replenished, until now, restoring our glutathione (GSH) levels quickly was not something that could be achieved easily.

Prior to the availability of gamma-glutamylcysteine (GGC), it took many months of tedious supplementation before even a small increase in glutathione (GSH) levels could be claimed to occur. It was therefore almost impossible to measure the effects that long-term supplementation of glutathione (GSH) and other molecules had on sports recovery. Studies to that effect had, at best, anecdotal evidence, if any.

Supplementation with gamma-glutamylcysteine (GGC) is different because it is the immediate precursor to glutathione. It works by being taken up by our cells and converted to glutathione (GSH) within hours of a single dose. Gamma-glutamylcysteine (GGC) provides the unique opportunity to increase glutathione (GSH) above normal resting state levels before, during and after exercise. This should provide buffers against the extreme production rate of ROS due to exercise depleting your glutathione (GSH), and creating a tissue-damaging oxidative stress environment.

Alternative supplements such as glutathione itself and N-acetylcysteine (NAC) supplements cannot increase glutathione (GSH) levels above what is called homeostasis, which means they cannot provide a buffer inside your cells to meet the demands of the extreme exercise undertaken by most athletes.

Increasing glutathione (GSH) levels via gamma-glutamylcysteine (GGC) consumption will minimize oxidative stress and should benefit exercise routines by increasing energy, stamina and shortening recovery times.

References

1. Kerksick, C. and D. Willoughby, The antioxidant role of glutathione and N-acetyl-cysteine supplements and exercise-induced oxidative stress. J Int Soc Sports Nutr, 2005. 2: p. 38-44.
2. Sen, C.K. and L. Packer, Thiol homeostasis and supplements in physical exercise. American Journal of Clinical Nutrition, 2000. 72(2 Suppl).
3. Houston, M.C., Nutraceuticals, Vitamins, Antioxidants, and Minerals in the Prevention and Treatment of Hypertension. Progress in cardiovascular diseases, 2005. 47(6): p. 396-449.
4. Wang, J.S. and Y.H. Huang, Effects of exercise intensity on lymphocyte apoptosis induced by oxidative stress in men. European Journal of Applied Physiology, 2005. 95(4): p. 290-297.
5. Traustadottir, T., et al., Oxidative stress in older adults: effects of physical fitness. Age (Dordr), 2012. 34(4): p. 969-82.
6. Cherkas, A., et al., Glucose as a Major Antioxidant: When, What for and Why It Fails? Antioxidants (Basel), 2020. 9(2).
7. Nielsen, H.B., et al., N-acetylcysteine does not affect the lymphocyte proliferation and natural killer cell activity responses to exercise. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, 1998. 275(4): p. R1227-R1231.
8. Childs, A., et al., Supplementation with vitamin C and N-acetyl-cysteine increases oxidative stress in humans after an acute muscle injury induced by eccentric exercise. Free Radical Biology and Medicine, 2001. 31(6): p. 745-753.
9. Ferreira, L.F., K.S. Campbell, and M.B. Reid, N-Acetylcysteine in Handgrip Exercise: Plasma Thiols and Adverse Reactions. International Journal of Sport Nutrition and Exercise Metabolism, 2011. 21(2): p. 146-154.
10. Paschalis, V., et al., N-acetylcysteine supplementation increases exercise performance and reduces oxidative stress only in individuals with low levels of glutathione. Free Radical Biology and Medicine, 2018. 115: p. 288-297.