Plasma concentrations of retinol in adults with non-severe COVID-19

Evidence indicates that vitamin A plays an important role in the prevention and treatment of respiratory infections owing to its antioxidant and immune system-modulating effects. The objective of this study was to describe plasma retinol concentrations in individuals with non-severe COVID-19 to investigate potential correlations with biological, clinical, anthropometric, biochemical, and hematological characteristics. A cross-sectional study was conducted in Brazil with 127 adults presenting at primary health care centers with flu-like symptoms for a duration of between 3 and 7 days. The concentration of retinol was calculated in micromoles per liter (μmol/L), and concentrations below 0.7 μmol/L (20 µg/dL) were considered to indicate a deficiency of vitamin A. The results demonstrated the presence of borderline concentrations of retinol in the sample, with a mean (standard deviation) of 0.70 μmol/L (0.35 μmol/L). The results indicated a reduction in retinol and β-carotene concentrations (p = 0.024), as well as a tendency towards lower vitamin A concentrations in individuals with anemia and high CRP, although without statistical significance (p > 0.05). Further research is required to elucidate the impact of nutritional status, including vitamin A concentrations, on the outcomes of non-severe COVID-19.