GSH deficiency

Cancer is associated with low glutathione levels. What lowers GSH ? It looks to me as though the A1 protein in commercial milk may be a factor, note this study also alleges the A1 protein also inhibits cysteine absorption. This is why I avoid most cheese, and only use A2 milk. Imagine all the people, eating all that cheese they eat and milk they drink. Does it cause a general lowering of GSH in the general population ? Why is milk promoted so heavily ? Did you also notice the link between A1 protein and diabetes and autism ? Looks like bad stuff to me.

https://www.ncbi.nlm.nih.gov/pubmed/27680716

http://www.a2milk.com