In regards to alcohol and GSH levels, I found my information in this article:
This is an excerpt: "It is also known that the levels of glutathione in the epithelial lining fluid are diminished in a number of lung disorders and environmental exposures including ARDS, idiopathic lung fibrosis, lung transplantation, HIV infection, ALCOHOL ABUSE, asbestos, and cystic fibrosis."
It also goes to say: "In this issue of CHEST, Bishop and colleagues report encouraging results from a small, double-blind, placebo-controlled clinical trial of inhaled glutathione in patients with cystic fibrosis. The rationale for this therapy lies in previous data reporting that glutathione levels in the lung epithelial lining fluid of patients with cystic fibrosis are low, and that cystic fibrosis lung disease is associated with increased oxidative damage. In addition, more recent studies have also demonstrated that the cystic fibrosis transmembrane conductance regulator (CFTR), which is defective in cystic fibrosis, regulates a substantial portion of glutathione efflux into the epithelial lining fluid...."
"...There are now three small clinical trials that have examined the effects of inhaled glutathione in patients with cystic fibrosis. Roum and colleagues were first to report the use of inhaled glutathione (600 mg bid for 3 days, approximately 17 mg/kg/d) in seven patients with cystic fibrosis. The glutathione therapy was well tolerated and produced a twofold increase in epithelial lining fluid glutathione levels. In addition, these investigators found diminished superoxide production from BAL cells after glutathione therapy...."
"...these regimens were well tolerated, increased epithelial lining fluid glutathione levels threefold to fourfold, and were associated with a significant improvement in the patient’s FEV1."
I did read the above mentioned article you linked, and it says this: "Because of all its functions, GSH is probably the most important antioxidant present in cells. Therefore, enzymes that help generate GSH are critical to the body's ability to protect itself against oxidative stress. ALCOHOL HAS BEEN SHOWN TO DEPLETE GSH LEVELS, particularly in the mitochondria, which normally are characterized by high levels of GSH needed to eliminate the ROS generated during activity of the respiratory chain."
So basically higher levels of GSH are good because it helps the body's ability to protect itself against oxidative stress (oxidative stress leads to lower lung function), but because in CF the CFTR channel is defective (CFTR channel regulates GSH levels), CFers get very low amounts of GSH, AND alcohol also lowers GSH levels, so again, alcohol leads to lowered levels of GSH, which leads to lower lung function, hence why patients in the US are now inhaled GSH or taking tablets.
Take a look at this article as well from Sharktank:
"Cystic fibrosis (CF) is characterized by accumulation of activated neutrophils and macrophages on the respiratory epithelial surface (RES); these cells release toxic oxidants, which contribute to the marked epithelial derangements seen in CF. These deleterious consequences are magnified, since reduced glutathione (GSH), an antioxidant present in high concentrations in normal respiratory epithelial lining fluid (ELF), is deficient in CF ELF. To evaluate the feasibility of increasing ELF GSH levels and enhancing RES antioxidant protection, GSH aerosol was delivered (600 mg twice daily for 3 days) to seven patients with CF. ELF total, reduced, and oxidized GSH increased (P <0.05, all compared with before GSH therapy), suggesting adequate RESdelivery and utilization of GSH."
"Together, these observations demonstrate the feasibility of using GSH aerosol to restore RES oxidant-antioxidant balance in CF and support the rationale for further clinical evaluation."