Proof of Concept: Effects of an Immune-Enhancing Formula on Clinical Markers of Critical Coronavirus Disease 2019 Cases

<b>Background/Objectives</b>: The rapid viral spread observed in coronavirus disease 2019 (COVID-19) is capable of inducing the secretion of excessive inflammatory cytokines. The resulting multi-organ damage is a severe complication that can be attenuated through adequate nutrition. Formulae enhanced with either glutamine or arginine are conditionally essential amino acids that have been proven to improve the condition of hospitalized patients. This retrospective study aimed to investigate the effects of administering an immune-enhancing enteral formula enhanced with arginine and glutamine on the clinical signs and biomarkers of patients with severe COVID-19. <b>Methods:</b> After checking the data of 232 patients enrolled in the biobank for completeness and eligibility, 31 patients with severe COVID-19 in the intensive care unit at Taipei Tzu Chi Hospital were grouped based on the type of enteral formula used: 16 patients received the control formula, and 15 patients received the immune-enhancing formula. Baseline characteristics, clinical signs, and inflammatory markers were analyzed for differences. <b>Results:</b> An increase in IL-10 levels in the intervention group was observed (<i>p</i> = 0.048). Changes in other inflammatory cytokine levels were insignificant. <b>Conclusions:</b> Providing an enteral formula enriched with glutamine and arginine to severe COVID-19 patients may help improve their anti-inflammatory marker levels. Further interventional study utilizing enteral formula enriched with glutamine and arginine is needed to confirm the findings of this study.