They are running an uncontrolled experiment on their own tissue
In contrast, melatonin levels were reduced in the tissues examined, particularly so in the brain
The product of this gene (i.e., GGT-rel) was shown to cleave the -glutamyl bond of LTC 4 (a glutathione S -conjugate) but not the -glutamyl substrates routinely used to assay GGT activity
Here are some other ways to help increase levels of glutathione, along with taking care to optimize vitamin D: limit alcohol consumption decrease exposure to POPs increase intake of other antioxidants to decrease overall oxidative stress increase intake of nutrients that promote glutathione production, such as NAC (N-acetylcysteine), 1000 mg/day, whey, or SAMe get enough magnesium and selenium in the diet, as both are necessary for glutathione production foods such as almonds, cruciferous vegetables, and even alcohol-free beer have been shown to raise glutathione levels, as has meditation
Figure 2A)