|Blueberries and other foods w/ tons of polyphenols are GSH boosters (Moskaug. 2005) and make supplements obsolete.|
Now, the absence of human studies should definitely ring an alarm bell in the head of every healthily skeptic supplement user, what it should not do, though is mislead you to believe that GSH supplements don't work in human beings.
Now this is where John P. Richie Jr. and his colleagues from the Penn State Cancer Institute, the Department of Microbiology and Immunology at the Penn State University College of Medicine and the Orentreich Foundation for the Advancement of Science, come into play. As the scientist state, their "objective was to determine the long-term effectiveness of oral GSH supplementation on body stores of GSH in healthy adults." (Richie. 2014)
Warning - keep an eye on your wallets: Even if the supplements work, they are probably going to be expensive and in view of the fact that "the increases were dose and time dependent, and levels returned to baseline after a 1-month washout period" (Richie. 2014), you will (a) have to take plenty to achieve maximal effects and (b) do that year-round. In view of the fact that we still don't have evidence of any downstream health benefits, I would thus be hesitant to recommend buying a GSH supplement at the moment - specifically if you are healthy, eat clean and work out!To this end, they conducted a 6-month randomized, double-blinded,placebo-controlled trial in the course of which the subjects, 41 women and 13 men (6 dropouts not included) with a normal BMI and no known health issues, consumed either ...
- an oral GSH supplement dosed at 250mg/day,
- an oral GSH supplement dosed at 1,000mg/day, or
- an identically looking placebo.
|Figure 1: Effects of 6 months GSH supplementation on ratio of oxidized to reduced GSH and natural killer cell cytotoxicity in healthy men and women aged 28-72y (Richie. 2014)|
These improvements had beneficial downstream effects on the overall status of the subjects' antioxidant defense system. A fact you can conclude based on the decreased ratio of oxidized (used) to reduced (fresh) glutathione in whole blood the scientists observed in their subjects after 6 months. These benefits came hand in hand with an increase in natural killer cytotoxicity (+100%), another potentially highly desirable health benefit.
- Aw, Tak Yee, Grazyna Wierzbicka, and Dean P. Jones. "Oral glutathione increases tissue glutathione in vivo." Chemico-biological interactions 80.1 (1991): 89-97.
- Favilli, Fabio, et al. "Effect of orally administered glutathione on glutathione levels in some organs of rats: role of specific transporters." British journal of nutrition 78.02 (1997): 293-300.
- Kariya, Chirag, et al. "A role for CFTR in the elevation of glutathione levels in the lung by oral glutathione administration." American Journal of Physiology-Lung Cellular and Molecular Physiology 37.6 (2007): L1590.
- Loven, Dean, et al. "Effect of insulin and oral glutathione on glutathione levels and superoxide dismutase activities in organs of rats with streptozocin-induced diabetes." Diabetes 35.5 (1986): 503-507.
- Moskaug, Jan Ø., et al. "Polyphenols and glutathione synthesis regulation." The American journal of clinical nutrition 81.1 (2005): 277S-283S.
- Richie Jr, John P., et al. "Randomized controlled trial of oral glutathione supplementation on body stores of glutathione." European journal of nutrition (2014): 1-13.