The main effects of stress are mainly on intestinal motility and permeability, visceral sensitivity, immune responses and gut microbiota composition (Qin et al., 2014)
Already, that category includes a wide range of ingredients vitamins, minerals, herbs and more that can be sold on promises to support general health and wellness, as long as they dont claim to treat specific conditions
The most notable is acetaminophen (Tylenol), which is metabolized using glutathione pathways
Furthermore, since in many developing countries unregistered and poorly regulated herbal products may be sold with little or no limitation, international regulatory policies are needed which take into account also of the new knowledge on the impact of pesticides on neurodevelopment and neurodegeneration
So it may be that the liver has to work extra hard to detoxify the body when its low 0on B12, even when there's no liver damage