Methionine:An essential amino acid that helps break down fats, prevents fat accumulation in the liver and arteries, and aids in detoxification processes
Other markers are not commonly measured either in clinical practice or in many clinical trials, making it difficult to interpret whether positive outcomes in some studies are due to correcting a deficiency or due to other pharmacological functions of B12
Dipeptidyl peptidase-4 inhibitors and gallbladder or biliary disease in type 2 diabetes: systematic review and pairwise and network meta-analysis of randomised controlled trials
NAD+ serves as an essential coenzyme for hundreds of enzymatic reactions, including those involved in energy production, DNA repair, and cellular signaling
Just look at the history of people with ME (myalgic encephalomyelitis) or with Long-Covid, and how they have been ill-diagnosed and not well treated, and you realize how mediocre the specific evaluation of many people with unexplained symptoms may have been
Severe deficiency can contribute to fatty liver changes, which is one reason choline gets framed as liver support. Details are summarized in the NIH ODS Choline fact sheet for health professionals