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Vitamin A Nutritional Status and Clinical Outcomes in COVID-19: A Systematic Review

Oliveira et al., Journal of Nutritional Science and Vitaminology, doi:10.3177/jnsv.69.395
Dec 2023  
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Vitamin A for COVID-19
12th treatment shown to reduce risk in January 2021
*, now known with p = 0.031 from 13 studies.
Lower risk for recovery and viral clearance.
No treatment is 100% effective. Protocols combine complementary and synergistic treatments. * >10% efficacy in meta analysis with ≥3 clinical studies.
3,800+ studies for 60+ treatments.
Systematic review of seven observational studies with 608 COVID-19 patients, showing an association between lower vitamin A levels and worse clinical outcomes including longer hospitalization, increased need for intensive care and mechanical ventilation, higher risk of respiratory complications like acute respiratory distress syndrome, and greater COVID-19 severity and mortality.
Currently there are 13 vitamin A studies and meta analysis shows:
Mortality42% lower [-133‑86%]
Ventilation unchanged [-76‑318%]
ICU admission48% lower [-40‑80%]
Hospitalization10% lower [-5‑23%]
Cases44% fewer [-26‑75%]
Oliveira et al., 31 Dec 2023, peer-reviewed, 11 authors. Contact:
This PaperVitamin AAll
Vitamin A Nutritional Status and Clinical Outcomes in COVID-19: A Systematic Review
Iara Katrynne, F Oliveira, Vanessa C Carvalho, Gabriela S Santos, V N Nayara, Monteiro, Margarete A F Azevedo, Henrique R Carlos, Lima, Emídio M M Neto, Maria Do Carmo, C Martins, Liania A Luzia, Patrícia H C Rondó, Adriana A Paiva
The role of vitamin A in the pathophysiological context of coronavirus disease 2019 (COVID-19) represents a current challenge, given the major impact of COVID-19 on morbidity and mortality and the importance of retinol in pulmonary and immunomodulatory functions. The aim of this review is to assess the relationship between vitamin A nutritional status and clinical outcomes in people with COVID-19. The PubMed, Web of Science, Scopus and ScienceDirect databases were used to search for observational studies that assessed retinol levels in hospitalized individuals with COVID-19, following the PRISMA recommendations. A total of 1,912 articles were identified and seven met the inclusion criteria. Four studies showed borderline or deficient retinol blood levels (retinol ,0.20 mg/L or ,0.70 mol/L) in people with COVID-19, associated with worsened clinical outcomes. In the other three studies lower mean values of this vitamin were identified in COVID-19 symptomatic groups compared to asymptomatic or convalescent groups that showed worse clinical outcomes. The results suggest a possible association between retinol and COVID-19 outcomes. However, there is a clear need to develop clinical trials to elucidate the role of vitamin A in the pathophysiological process of COVID-19.
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