Effects of Ethanol in ME/CFS and the GD-MCB hypothesis
Hi, all.
As has been suggested a couple of times on this thread, the toxic effect of ethanol in most PWCs is explained very well by the Glutathione Depletion--Methylation Cycle Block hypothesis. In fact, ethanol intolerance could contribute to diagnosis of ME/CFS for most cases, in my opinion, because it directly interrogates what I believe is the hallmark mechanism in the pathophysiology of ME/CFS.
Ethanol hits PWCs right where it hurts. Specifically, ethanol is metabolized by the liver. The liver is normally the main producer of glutathione in the body, and as other tissues become depleted in glutathione, the liver is the main bulwark that keeps PWCs from going into multiple organ failure and death. It has first access to amino acids coming from food in the gut, from which to make glutathione, and it has a complete transsulfuration pathway to make cysteine from methionine, as well as the alternative BHMT pathway for its methylation cycle, upstream of glutathione synthesis. In short, it is in the best position to hold the line when glutathione becomes depleted bodywide, and thus keep PWCs alive.
Unfortunately (see abstract below) ethanol causes oxidative stress particularly in the liver, and depletes glutathione there, worsening the scarcity that already exists.
However, in agreement with the present results of this poll and a few of the posts in this thread, I have also encountered a small number of PWCs who are able to tolerate ethanol. In cases in which they have shared their pre-onset history with me, I have found that they had a fairly high ethanol consumption before becoming ill with ME/CFS, and I have therefore hypothesized that their livers were able to develop a greater capacity for metabolizing ethanol before they became ill, and this greater capacity remains. At least one of the pathways for metabolizing ethanol in the liver is inducible, meaning that it can be expanded to greater capacity with greater chronic exposure to ethanol.
On the "bright" side (not really all that bright, I realize), if it were not for the toxicity of ethanol in CFS, I think it would be very likely that many would become alcoholics and succumb from cirrhosis of the liver, in an attempt to counter the pain and secondary depression. Sadly, it's sort of a case of the devil and the deep blue sea. But, as I continue to emphasize here, there is hope for lifting the partial methylation cycle block and restoring glutathione by the methylation-type treatments, and I encourage people to consider them, if they have not already done so.
Best regards.
Rich
Semin Liver Dis. 2009 May;29(2):141-54. Epub 2009 Apr 22.
Oxidative stress and alcoholic liver disease.
Wu D, Cederbaum AI.
Source
Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York 10029, USA.
Abstract
Reactive oxygen species (ROS) are highly reactive molecules that are naturally generated in small amounts during the body's metabolic reactions and can react with and damage complex cellular molecules such as lipids, proteins, or DNA. This review describes pathways involved in ROS formation, why ROS are toxic to cells, and how the liver protects itself against ROS. Acute and chronic ethanol treatment increases the production of ROS, lowers cellular antioxidant levels, and enhances oxidative stress in many tissues, especially the liver. Ethanol-induced oxidative stress plays a major role in the mechanisms by which ethanol produces liver injury. Many pathways play a key role in how ethanol induces oxidative stress. This review summarizes some of the leading pathways and discusses the evidence for their contribution to alcohol-induced liver injury.
PMID: 19387914