Effects of Green tea supplementation on the CRP, ESR, and CBC in the patients with COVID-19, a double-blind placebo-controlled clinical trial

Background This study investigated the effects of green tea extract on biomarkers and signs of COVID-19 patients who were hospitalized. Methods This study was a double-blind clinical trial that involved 74 patients who were under hospital care. These individuals were randomly divided into two groups. One group received a 900mg/d dosage of green tea supplement along with standard patient care, while the other group received a placebo alongside standard patient care. This administration lasted for 14 days. Blood factors and anthropometric factors were measured before and after the intervention. Additionally, dietary intake was assessed during the study. Results After the intervention, there was a significant decrease in C-reactive protein (CRP) [Mean Differences (MD)18.34 and 95%CI (8.05 to 28.62)] and Erythrocyte Sedimentation Rate (ESR) [MD 16.68 and 95%CI (7.41 to 25.94)] levels in the green tea group compared to the placebo group. There were also significant changes in neutrophils, lymphocytes, red blood cells (RBC), and blood oxygen saturation in the green tea group(p < 0.05). However, there were no significant differences in other blood indices between the two groups. Conclusions The results suggest that green tea extract supplementation may positively affect inflammation and blood markers in COVID-19 patients and potentially improve blood oxygen saturation levels. Trial registration IRCT20150711023153N3 (https//irct.behdasht.gov.ir/trial/55948), Registration date 20210604