Results of a six-month randomized, double-blinded, placebo-controlled trial indicated that a daily glutathione dose of 1,000 milligrams was associated with a greater than two-fold increase in natural killer (NK) cell activity, compared to placebo.
“Seeing the two-fold increase in NK cell activity from glutathione supplementation indicates that glutathione could be playing an important role in boosting the body’s immune system,” said Dr John Richie of Penn State University, who led the research and has been studying glutathione for more than 30 years.
The study’s findings, which are published in the European Journal of Nutrition appear to validate findings from a separate survey commissioned by Kyowa Hakko, which found that 84% of consumers looking for ways to support their less-than-perfect body defenses, and 83% believing there are things they can do proactively to help boost their immune health.
Dr Richie and his co-workers recruited 54 healthy adults (41 women) with a mean age of 46.6 years and randomly assigned them to one of three groups: One group received placebo, while the other two groups received daily glutathione (Setria) doses of 250 or 1,000 mg/day for six months.
Results showed that both doses were associated with increased blood levels of glutathione after one, three and six months, compared with baseline values. At six months, mean glutathione levels increased 30-35% in erythrocytes, plasma, and lymphocytes, and 260% in buccal cells in the high dose group, while blood and erythrocytes levels of glutathione increased by 17 and 29%, respectively, in the low dose group.
Natural killer cytotoxicity increased two fold in the high-dose group versus placebo at 3 months, added the researchers.
“While the mechanisms for these effects [immune system support] are not known, they are consistent with previous in vitro studies demonstrating the importance of intracellular GSH levels in NK cytotoxic activity,” they wrote. “These studies show that even partial depletion of intracellular GSH can inhibit the effector phase of cytotoxic cell response as well as IL-2-dependent functions. Our results are also consistent with a previous clinical study in which low intracellular GSH levels were correlated with NK cell activity.
“Overall, the present findings provide a basis for conducting larger studies focusing on immune function.”
The study was supported by Kyowa Hakko Bio Co., Ltd.
Source: European Journal of Nutrition
Published online ahead of print, doi: 10.1007/s00394-014-0706-z
“Randomized controlled trial of oral glutathione supplementation on body stores of glutathione”
Authors: J.P. Richie Jr., S. Nichenametla, W. Neidig, et al.