The effectiveness of relative dose response to retinol intake as an evaluation of vitamin A status of cirrhotic patients.

BACKGROUND

The liver is the main organ involved in homeostasis, metabolism and the storage of retinol. During the fibrotic process, hepatic stellate cells lose their lipid drops, and retinol reserves may deplete. Thus, the present study aimed to evaluate serum retinol levels (RL), hepatic retinol storage and dietary vitamin A intake in cirrhotic patients.

METHODS

RL were measured by high-performance liquid chromatography in fifty-eight cirrhotic patients. Fasting RL <1.05 μmol L⁻¹ indicates vitamin A deficiency (VAD). A relative dose response (RDR) to oral retinol ≥20% indicates an inadequate hepatic retinol reserve (positive test). Severe malnutrition was defined as a mid-arm muscle circumference (MAMC) and/or triceps skinfold thickness (TSF) below the 5th percentile and moderate malnutrition as MAMC and/or TSF below the 10th percentile. Vitamin A daily intake was estimated by a specific questionnaire. The Child-Pugh classification of liver disease severity and the Model for End-Stage Liver Disease were used.

RESULTS

Low RL were found in 60% of the patients. Twenty-three cirrhotic patients had adequate fasting RL (RL = 1.34; 1.05-2.12 μmol L⁻¹) and negative RDR, indicating efficient liver stores. Among thirty-five cirrhotic patients with low RL, 43% had negative RDR (RL = 0.42; 0.06-0.82 μmol L⁻¹) and 57% had positive RDR (RL = 0.45; 0.09-0.93 μmol L⁻¹). Malnutrition (36%) and inadequate vitamin A intake (55%) were not associated with fasting RL or RDR.

CONCLUSIONS

VAD was highly prevalent in cirrhotic patients. However, in those with low serum RL and negative RDR, factors other than inadequate vitamin A intake, such as impaired hepatic vitamin A mobilization and intestinal vitamin A malabsorption, which were not examined in the present study, could have influenced the negative results obtained by the RDR method.