Influence of quercetin supplementation on disease risk factors in community-dwelling adults

J Am Diet Assoc. 2011 Apr;111(4):542-9. doi: 10.1016/j.jada.2011.01.013.


Background: In vitro data indicate quercetin has antioxidative and anti-inflammatory functions with the potential to lower disease risk factors, but data in human beings are limited.

Objective: The objective of this study was to investigate the effect of quercetin, vitamin C, and niacin supplements (500 mg quercetin, 125 mg vitamin C, and 5 mg niacin [Q-500]; 1,000 mg quercetin, 250 mg vitamin C, and 10 mg niacin [Q-1,000]), on disease risk factors in a large group of community adults (n=1,002, 60% women) varying widely in age and body mass index.

Design: Subjects were randomized into one of three groups (placebo, Q-500, or Q-1,000) and ingested supplements for 12 weeks. Blood samples were taken pre- and postsupplementation, and plasma quercetin, inflammatory markers (ie, C-reactive protein and five cytokines), diagnostic blood chemistries, blood pressure, and blood lipid profiles were measured.

Results: Plasma quercetin increased in the Q-500 and Q-1,000 groups. No differences in blood chemistries were found except for a small decrease in serum creatinine and increase in glomerular filtration rate in Q-500 and Q-1,000 groups. A small decrease in mean arterial blood pressure was measured for Q-500 and Q-1,000 groups compared to placebo. A difference in serum total cholesterol was measured between Q-500 and placebo groups, and there was small decrease in high-density lipoprotein cholesterol levels in the Q-1,000 group. Change in inflammatory measures did not differ between groups except for a slight decrease in interleukin-6 for the Q-1,000 group.

Conclusions: Q-500 or Q-1,000 supplementation for 12 weeks had a negligible influence on disease risk factors.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Analysis of Variance
  • Antioxidants / administration & dosage*
  • Antioxidants / metabolism
  • Ascorbic Acid / administration & dosage
  • Ascorbic Acid / blood
  • Blood Pressure / drug effects
  • Body Mass Index
  • C-Reactive Protein / metabolism
  • Cardiovascular Diseases / blood
  • Cardiovascular Diseases / prevention & control*
  • Chronic Disease / prevention & control
  • Cytokines / blood
  • Dietary Supplements
  • Dose-Response Relationship, Drug
  • Female
  • Humans
  • Lipid Metabolism / drug effects
  • Male
  • Middle Aged
  • Niacin / administration & dosage
  • Niacin / blood
  • Quercetin / administration & dosage*
  • Quercetin / blood*
  • Risk Factors
  • Young Adult


  • Antioxidants
  • Cytokines
  • Niacin
  • C-Reactive Protein
  • Quercetin
  • Ascorbic Acid