The Effect of Olive Leaf Extract on Upper Respiratory Illness in High School Athletes: A Randomised Control Trial
Discipline of Nutrition and Dietetics, Faculty of Medical and Health Science, The University of Auckland, Auckland 1023, New Zealand
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Nutrients 2019, 11(2), 358; https://doi.org/10.3390/nu11020358
Received: 15 January 2019
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Revised: 6 February 2019
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Accepted: 7 February 2019
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Published: 9 February 2019
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) p-value = 0.02) when supplemented with OLE. The dietary intakes of the athletes were sub-optimal with regard to immune support. OLE supplementation over a season did not significantly reduce URI incidence, but did decrease duration in high school athletes, potentially aiding return to play.
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Keywords:
polyphenols; sport; immunity; athlete; respiratory; oleuropein; hydroxytyrosol
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MDPI and ACS Style
Somerville, V.; Moore, R.; Braakhuis, A. The Effect of Olive Leaf Extract on Upper Respiratory Illness in High School Athletes: A Randomised Control Trial. Nutrients 2019, 11, 358. https://doi.org/10.3390/nu11020358
AMA Style
Somerville V, Moore R, Braakhuis A. The Effect of Olive Leaf Extract on Upper Respiratory Illness in High School Athletes: A Randomised Control Trial. Nutrients. 2019; 11(2):358. https://doi.org/10.3390/nu11020358
Chicago/Turabian StyleSomerville, Vaughan, Rachel Moore, and Andrea Braakhuis. 2019. "The Effect of Olive Leaf Extract on Upper Respiratory Illness in High School Athletes: A Randomised Control Trial" Nutrients 11, no. 2: 358. https://doi.org/10.3390/nu11020358
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