Effects of Micronutrients or Conditional Amino Acids on COVID-19 Related Outcomes: An Evidence Analysis Center Scoping Review

Rozga, Mary; Cheng, Feon W.; Moloney, Lisa; Handu, Deepa

Abstract Recent narrative reviews have described the potential efficacy of providing individuals infected with COVID-19 with additional micronutrients to reduce disease severity. While there are compelling reasons why providing additional micronutrients or conditional amino acids may affect COVID-19-related outcomes, evidence is lacking. The objective of this scoping review is to explore and describe the literature examining the effect of providing additional micronutrients or conditional amino acids (glutamine, arginine) in adults with conditions or infections similar to COVID-19 infection on COVID-19 related health outcomes. A literature search of the MEDLINE database and hand-search of Cochrane Database of systematic reviews retrieved 1,423 unique studies, and eight studies were included in this scoping review. Four studies examined a target population with ventilator-related pneumonia and acute respiratory distress syndrome, while the other four studies included patients who were at risk for ventilator-associated pneumonia. Interventions included intravenous vitamin C, intramuscular vitamin D, enteral and intramuscular vitamin E, enteral zinc sulfate, and oral and parenteral glutamine. In six of the eight included studies, baseline status of the nutrient of interest was not reported and, thus, it is uncertain how outcomes may vary in the context of nutrient deficiency or insufficiency compared to sufficiency. In the absence of direct evidence examining efficacy of providing additional micronutrients or conditional amino acids to standard care, registered dietitian nutritionists (RDNs) must rely on clinical expertise, and indirect evidence to guide medical nutrition therapy (MNT) for patients infected with COVID-19.