Quercetin supplementation and upper respiratory tract infection: A randomized community clinical trial
Heinz SA, Henson DA, Austin MD, Jin F, Nieman DC
Published in Pharmacological Research
Methodology
Randomized, double-blind, placebo-controlled community trial of 500 or 1000 mg/day quercetin for 12 weeks with daily WURSS symptom logs
Key Findings
No significant group differences in upper respiratory tract infection rates or symptoms overall, or by gender, BMI or age. In a post hoc subgroup of fitter adults aged 40+ (n=325), the 1000 mg/day group had 36% lower URTI severity and 31% fewer sick days.
Conclusions
Quercetin did not reduce respiratory infection rates in the general community sample; benefit was confined to a post hoc subgroup.
Limitations
Self-reported outcomes, no laboratory confirmation of infection, subgroup findings were exploratory and not pre-specified.
Supplements Studied
for all subjects combined, quercetin supplementation over 12 weeks had no significant influence on URTI rates or symptomatology compared to placebo
Outcomes Measured
quercetin supplementation over 12 weeks had no significant influence on URTI rates or symptomatology compared to placebo
Related Health Concerns
Study Details
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This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.