Tier 2 — strong

The effect of 24-week continuous intake of quercetin-rich onion on age-related cognitive decline in healthy elderly people: a randomized, double-blind, placebo-controlled, parallel-group comparative clinical trial

Jun Nishihira, Mie Nishimura, Masanori Kurimoto, Hiroyo Kagami-Katsuyama, Hiroki Hattori, Toshiyuki Nakagawa, Takato Muro, Masuko Kobori
Journal of clinical biochemistry and nutrition 2021 69(2):203-215

Bibliography

PubMed
PMID 34616111
PubMed Central
PMC8482389
DOI
10.3164/jcbn.21-17
Funding
Reported funding/support: This research was supported by grants from the Project of the Bio-oriented Technology Research Advancement Institution (R&D matching funds on the field for Knowledge Integration and Innovation).
Competing interests
Reported disclosure: No potential conflicts of interest were disclosed.

Study snapshot

DesignRandomized double-blind placebo-controlled food trial
ModelHuman intervention research
Sample70 healthy Japanese adults aged 60–79
InterventionQuercetin-rich onion providing 50 mg/day aglycone equivalent versus quercetin-free onion
Duration24 weeks
EndpointsSource-specific outcomes described in the key findings

What the study showed, in plain terms

Published in 2021, this source examined brain, cognition and sleep. Design: Randomized double-blind placebo-controlled food trial. Sample/model: 70 healthy Japanese adults aged 60–79. The exposure or intervention was Quercetin-rich onion providing 50 mg/day aglycone equivalent versus quercetin-free onion. Follow-up or treatment period: 24 weeks.

The onion intervention improved MMSE and selected emotional or partner-reported measures.

Food intervention in healthy older adults with several outcomes. It does not establish dementia prevention or equivalence to a capsule formulation.

Continue with Quercetin Data Center

For topic-level interpretation, read Quercetin for Brain Fog, Memory and Sleep: Human Evidence. This is a related guide; the citation panel separately identifies articles that directly cite this paper.

Key findings

  • The onion intervention improved MMSE and selected emotional or partner-reported measures.
  • The recorded outcome domains were Source-specific outcomes described in the key findings.
  • The result applies to the tested exposure: Quercetin-rich onion providing 50 mg/day aglycone equivalent versus quercetin-free onion; 24 weeks.

What this study can and cannot tell us

  • Food intervention in healthy older adults with several outcomes. It does not establish dementia prevention or equivalence to a capsule formulation.
  • An individual controlled trial must be interpreted alongside its comparator, sample size, endpoint selection and independent replication. It does not validate a different commercial formulation or a general longevity claim.
  • Source basis: Source check: accessible full text and indexed metadata. Missing method details, funding information or participant denominators are not inferred.

Related papers in the corpus

Tier 2
Assessment of the Efficacy of Quercetin in Adult Patients With Autism Spectrum Disorder: A Randomized, Triple-Blind, Placebo-Controlled Trial
Anahid Rezaeifar et al. · Human psychopharmacology · 2026
Tier 2
Two-month period of 500 mg lecithin-based delivery form of quercetin daily dietary supplementation counterbalances chronic fatigue symptoms: A double-blind placebo controlled clinical trial
Mariangela Rondanelli et al. · Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie · 2023
Tier 2
Memory-Enhancing Effect of 8-Week Consumption of the Quercetin-Enriched Culinary Herbs-Derived Functional Ingredients: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial
Jintanaporn Wattanathorn et al. · Foods (Basel, Switzerland) · 2022

Citation network

Articles citing this research paper

1 article

Biohack Blueprint analyses that reference this study in their evidence base.

Editorial review

Reviewed by the Biohack Blueprint research team

Last verified

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