Liver and vitamin B₁₂ parameters in patients with anorexia nervosa before and after short-term weight restoration

Hepatic involvement in anorexia nervosa (AN) has been previously reported, but a link to elevated vitamin B₁₂ concentrations, which can be a sign for liver damage, has not been thoroughly examined. We measured liver enzymes (alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase) and vitamin B₁₂ parameters (total B₁₂, holotranscobalamin, methylmalonic acid) in the plasma of young female patients with acute AN (n=77) and after short-term weight restoration (n=58, median body mass increase=25%), in comparison to healthy control participants (n=63). For a comprehensive assessment of vitamin B₁₂ status, the combined marker cB₁₂ was calculated. In acute AN, activities of alanine aminotransferase and gamma-glutamyltransferase as well as holotranscobalamin concentrations were elevated, and alanine aminotransferase activities positively correlated with total B₁₂, holotranscobalamin and cB₁₂ in patients with elevated liver enzyme activities. After weight restoration, alanine aminotransferase activities and holotranscobalamin concentrations were elevated, and cB₁₂ increased above the level of the healthy control group. The present study provides further evidence for a hepatic involvement in acute AN in concert with vitamin B₁₂ parameters and points to refeeding-associated alterations of liver and vitamin B₁₂ parameters. Future studies should include non-invasive methods to characterize hepatic involvement and evaluate vitamin B₁₂ status as a potential marker of liver damage/irritation.