Trial reportNutrients2019
The Effect of Olive Leaf Extract on Upper Respiratory Illness in High School Athletes: A Randomised Control Trial.
Trial report in Nutrients, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT05685901 (Ensayo clínico Aleatorizado y Controlado Para la evaluación de la Eficacia y Seguridad de la Inmunoprofilaxis orofaríngea Con Aceite de Oliva Rico en Polifenoles Como atenuación y prevención de la Enfermedad Infecciosa Por el Coronavirus SARS-CoV-2.), which is not on this map. Cited by 14 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Ensayo clínico Aleatorizado y Controlado Para la evaluación de la Eficacia y Seguridad de la Inmunoprofilaxis orofaríngea Con Aceite de Oliva Rico en Polifenoles Como atenuación y prevención de la Enfermedad Infecciosa Por el Coronavirus SARS-CoV-2.
Who cites it
14 citing papers in PubMed, 30 citations in OpenAlex.
- Buccopharyngeal route administered high polyphenolic olive oil and COVID-19: A pilot clinical trial.Immunity, inflammation and disease · 2023Trial
- A comprehensive review ofRSC advances · 2026Review
- OverallFrontiers in microbiology · 2025Article
- Potential Therapeutic Properties ofPharmaceuticals (Basel, Switzerland) · 2024Article
- Nutritional Supplements for Skin Health-A Review of What Should Be Chosen and Why.Medicina (Kaunas, Lithuania) · 2023Review
- Anti-Inflammatory Effects of Olive Leaf Extract and Its Bioactive Compounds Oleacin and Oleuropein-Aglycone on Senescent Endothelial and Small Airway Epithelial Cells.Antioxidants (Basel, Switzerland) · 2023Article
- Role of Olive Bioactive Compounds in Respiratory Diseases.Antioxidants (Basel, Switzerland) · 2023Review
- Updated Organic Composition and Potential Therapeutic Properties of Different Varieties of Olive Leaves fromPlants (Basel, Switzerland) · 2023Article
- Polyphenols in the Mediterranean Diet: From Dietary Sources to microRNA Modulation.Antioxidants (Basel, Switzerland) · 2021Review
- Olive Tree in Circular Economy as a Source of Secondary Metabolites Active for Human and Animal Health Beyond Oxidative Stress and Inflammation.Molecules (Basel, Switzerland) · 2021Review
- Oromucosal immunomodulation as clinical spectrum mitigating factor in SARS-CoV-2 infection.Scandinavian journal of immunology · 2021Article
- A Quantitative Phytochemical Comparison of Olive Leaf Extracts on the Australian Market.Molecules (Basel, Switzerland) · 2020Article
- Review
- Formulation of a Phenol-Rich Extract from Unripe Olives (Molecules (Basel, Switzerland) · 2020Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 1 institution in 1 country.
Funding
Abstract
Upper respiratory illness (URI) has a major impact on both training and competition in an athletic setting. High school athletes are a sub-category who have reported higher illness rates than professional and sub-elite high school athletes of the same sport. Olive leaf extract (OLE) is an over-the-counter supplement that contains polyphenols, notably oleuropein and hydroxytyrosol, that have antiviral, antibacterial, anti-inflammatory and antioxidant properties that may reduce URI rates. Thirty-two high school students who play sport for the elite team at their school were recruited to a randomised controlled trial and allocated to a daily placebo or OLE (extent equivalent to 20 g of olive leaf, containing 100 mg oleuropein) supplementation for nine weeks during their competitive season. Twice weekly measures of wellbeing, training load and respiratory illness (sporting upper respiratory illness (SUPPRESS) questionnaire) were recorded at trainings, meetings or games. There was no significant difference in illness incidence (odds ratio (OR): 1.02 (95% confidence interval (CI) 0.21⁻4.44)), but there was a significant 28% reduction in sick days (OR: 0.72 (95% CI 0.56⁻0.93)
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.