Tier 2 — strong

Higher plasma quercetin levels following oral administration of an onion skin extract compared with pure quercetin dihydrate in humans

Constanze Burak, Verena Brüll, Peter Langguth, Benno F Zimmermann, Birgit Stoffel-Wagner, Udo Sausen, Peter Stehle, Siegfried Wolffram, Sarah Egert
European journal of nutrition 2017 56(1):343

Bibliography

PubMed
PMID 26482244
DOI
10.1007/s00394-015-1084-x
Funding
Funding was not specified in the indexed record or the disclosure metadata available for this entry.
Competing interests
A competing-interest declaration was not available in the indexed record or the disclosure metadata used for this entry.

Study snapshot

DesignRandomized single-blind diet-controlled crossover pharmacokinetic trial
ModelHuman intervention research
Sample12 healthy adults; 6 men and 6 women
InterventionOnion-skin extract providing about 163 mg quercetin versus dihydrate providing 134 mg aglycone equivalent
DurationSingle-dose periods; 24-hour blood sampling
EndpointsExposure and pharmacokinetics

What the study showed, in plain terms

Published in 2017, this source examined forms, absorption and food sources. Design: Randomized single-blind diet-controlled crossover pharmacokinetic trial. Sample/model: 12 healthy adults; 6 men and 6 women. The exposure or intervention was Onion-skin extract providing about 163 mg quercetin versus dihydrate providing 134 mg aglycone equivalent. Follow-up or treatment period: Single-dose periods; 24-hour blood sampling.

Measured quercetin exposure and peak concentrations were higher after the onion-skin extract.

Small acute study with different administered aglycone-equivalent amounts. It does not establish better disease outcomes or a universal ranking of forms.

Continue with Quercetin Data Center

For topic-level interpretation, read Foods High in Quercetin: Practical Sources and Portions. This is a related guide; the citation panel separately identifies articles that directly cite this paper.

Key findings

  • Measured quercetin exposure and peak concentrations were higher after the onion-skin extract.
  • The recorded outcome domains were Exposure and pharmacokinetics.
  • The result applies to the tested exposure: Onion-skin extract providing about 163 mg quercetin versus dihydrate providing 134 mg aglycone equivalent; Single-dose periods; 24-hour blood sampling.

What this study can and cannot tell us

  • Small acute study with different administered aglycone-equivalent amounts. It does not establish better disease outcomes or a universal ranking of forms.
  • A change in blood exposure or a metabolic marker is not a demonstrated improvement in symptoms, disease events or lifespan. The tested formulation and co-administered medicines matter.
  • Source basis: Source check: PubMed abstract and indexed metadata; full methods were not independently confirmed for this entry. Missing method details, funding information or participant denominators are not inferred.

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Editorial review

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Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction Dr. Amr Yasser, PhDCardiometabolic, Musculoskeletal, Gut & Bioavailability Dr. Abdulla Mostafa, PhDCellular Senescence, Neurological, Mitochondrial & Brain-Ageing Biology