This systematic review and network meta-analysis investigated whether different vitamins, nutrients and dietary supplements can affect recovery and inflammation in adults with COVID-19. The researchers compiled 45 randomized controlled trials from 18 countries with a total of 3,793 patients.
The results show that some supplements can affect individual markers of inflammation. Vitamin C together with standard treatment reduced the inflammatory marker IL-6, while nanocurcumin increased the number of lymphocytes. Pomegranate juice also affected the ratio between neutrophils and lymphocytes, but the results were more uncertain and partly contradictory.
Most importantly, however, the researchers did not see any definite improvement in several clinically important outcomes. The dietary supplements did not reduce mortality and had no clear effect on, among other things, CRP, white blood cell count, neutrophils, fever, headache, cough or shortness of breath compared with standard treatment.
The researchers also emphasize that the results must be interpreted with caution. For several comparisons, the number of patients was small, a large part of the results were based on indirect comparisons and the evidence was often assessed as low or very low. Of the 45 included studies, 13 had a high risk of bias and a further eight had some methodological issues. The researchers themselves point out that the very large estimated reduction in IL-6 with vitamin C is likely unstable and should not be considered a reliable measure of treatment effect. The conclusion is therefore not that vitamins or dietary supplements can replace standard Covid treatment. Rather, the study shows that certain supplements can possibly affect specific laboratory values and therefore may be interesting as complementary treatment in certain situations. However, there is not yet strong enough evidence to say that they improve the most important clinical outcomes, and larger and better randomized studies are needed.
Text translated from Swedish, originally written by Patrik Andersson and published in Facebook group SARS-CoV-2 Omvärldsbevakning