Background  

The objective of the present study was to investigate vitamin A nutritional status in individuals with class III obesity through a biochemical indicator (retinol and β-carotene serum levels), correlating these findings with non-alcoholic fatty liver disease (NAFLD) presence and its risk factors.

Methods  

The studied population was composed of 145 patients with morbid obesity [body mass index, BMI ≥ 40 kg/m²) of both sexes. Retinol and β-carotene serum levels were assessed by high performance liquid chromatography. The cutoff values used for serum retinol and β-carotene inadequacy were <1.05 μmol/l and ≤40 μg/dl, respectively. Insulin resistance (IR) was assessed through homeostasis model assessment index (HOMA) method. Biochemical parameters of liver enzymes, lipid profile, and glycemia were analyzed. Anthropometric measurements were conducted. NAFLD diagnosis was performed through magnetic resonance.

Results  

NAFLD prevalence in the group was 71%. An inadequacy of 11.3 and 41.7% of retinol and β-carotene serum levels, respectively, was found when NAFLD was present. A significant correlation of serum retinol with albumin liver and total bilirubin was found. As regards β-carotene, a positive correlation for HDL-c variable and a negative correlation for the HOMA-IR, weight, and BMI variables were observed. There was a significant association between IR presence and retinol and β-carotene inadequacy.

Conclusion  

The high inadequacy of retinol and β-carotene nutritional status in the sample, with a higher inadequacy in those with NAFLD, suggests an increase in the utilization of vitamin A in this group related to the fight against the oxidative stress to what they are exposed to. The significant association between retinol and β-carotene with IR supports the hypothesis that vitamin A may have a protector effect on IR pathogenesis.