Association between Serum Vitamin B12 Levels and the Degree of Steatosis in Patients with Nonalcoholic Fatty Liver Disease

PURPOSE: A relationship between liver diseases and serum vitamin B12 levels was observed in previous reports. The purpose of this study was to determine if a similar relationship existed between vitamin B12 and nonalcoholic fatty liver disease (NAFLD), a common chronic liver disorder. MATERIALS AND METHODS: A total of 45 consecutive patients with NAFLD formed the NAFLD group, whereas 30 healthy controls (HC) formed the HC group. The subjects in all of the groups were of similar age and body mass index (BMI). A fatty liver is described in 3 ultrasonographic grades. Fasting blood samples were obtained, and serum vitamin B12 levels were measured. In addition, liver enzymes including aspartate aminotransferase, alanine aminotransferase (ALT), and alkaline phosphatase, and folic acid and other serum parameters were evaluated. The Mann-Whitney U test, χ2 test, and Spearman correlation analysis were used to compare the vitamin B12 levels and other serum parameters in both groups. RESULTS: The mean ± SD age and BMI of the NAFLD were 47.2 ± 11.2 and 28.8 ± 3.5. The mean ± SD age and BMI of the HC were 47.1 ± 8.8 and 27.7 ± 2.9, respectively. The serum aspartate aminotransferase and ALT levels of the patients with NAFLD were statistically higher compared with those of the controls (P = 0.001). The levels of vitamin B12 and folate were statistically lower in the NAFLD patients compared with those of the controls (P < 0.05). We found that there was a reduction of vitamin B12 levels, especially in grade 2 to grade 3 hepatosteatosis. In addition, in the Spearman correlation analysis between the vitamin B12 levels and ALT, the grade of fatty liver and the liver dimension were found to have an important negative correlation. CONCLUSION: The serum vitamin B12 levels were significantly lower in the patients with NAFLD than in those of the control group; however, these still remain in the reference range. Consequently, low vitamin B12 levels may be associated with NAFLD especially in grade 2 to grade 3 hepatosteatosis.