Vitamin B12 Parameters Research Articles

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.

Iron, folate and vitamin B12 parameters in HIV-1 infected patients with anaemia in southern Brazil

We conducted a study to determine the role of iron, folate and vitamin B12 in HIV-infected patients with anaemia attending a tertiary-care hospital in southern Brazil. Low serum folate levels were found in 14 (41%) HIV-infected patients; parameters of iron deficiency such as low transferring saturation index and ferritin in 10 (30%); and combined folate and iron deficiency in five (14%). Vitamin B12 deficiency was found in only two (6%) patients who presented with mean corpuscular volumes within the normal range. Our study has shown that folate and iron deficiency were frequently detected in HIV-infected patients at our institution, and should be considered in the differential diagnosis of anaemia in all HIV-infected patients independent of their HIV stage of progression.