glutathione is destroyed in the gastro intestinal tract Role of Cancer: From Mechanisms to Therapies Dissecting the Role of Gut-Mediated
Description
Keep in mind that little hygiene can create significant differences in safety

Among the patients in ICU was also found in some studies that the incidence of ARDS was 70% in patients with a positive history for chronic alcohol abuse compared to about 31% in those without (Figure 3)

Plant-based sources are not as common

Prospective and controlled studies of the actions of insulin and catecholamine in fat cells of obese women following weight reduction

For a detailed review of peer-reviewed research on systemic effects, see this peer-reviewed review article
