The Application of Olive-Derived Polyphenols on Exercise-Induced Inflammation: A Scoping Review

There is current scientific interest pertaining to the therapeutic effects of olive-derived polyphenols (ODPs), in particular their associated anti-inflammatory properties, following the wealth of research surrounding the physiological impact of the Mediterranean Diet (MD). Despite this association, the majority of the current literature investigates ODPs in conjunction with metabolic diseases. There is limited research focusing on ODPs and acute inflammation following exercise, regardless of the knowledge surrounding the elevated inflammatory response during this time. Therefore, the aim of this scoping review is to understand the impact ODPs may have on exercise-induced inflammation.

This scoping review was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScRs). The literature searches were conducted in PubMed and EBSCOhost and considered for review if records reported original data, examined olives, olive-derived nutrients, food sources, or ODPs in conjunction with exercise-induced inflammation (including known causes, associations, and proxy measures).

Seven studies investigated ODPs and exercise-induced inflammation, providing commentary on reduced oxidative stress, inflammatory biomarkers, and immune biomarkers, enhanced antioxidant defenses and modulations in mitochondrial function, albeit in low numbers. An average of 100.9 mg∙d^-1 ODPs were supplemented for an average of 40 days, with hydroxytyrosol (HT) being the primary ODP investigated. Six studies employed individual aerobic exercise as their stimulus, whilst one study investigated the impact of an acute dose of ODP.

There is a limited consensus on the direction of isolated HT in human models, whereas animal models suggest a reduced inflammatory response following ≥2 weeks HT supplementation in conjunction with chronic exercise. Future research should initially investigate the inflammatory response of ODP, with particular focus on HT, and aim to identify an optimum dose and time course for supplementation surrounding exercise to support acute recovery and exercise adaptations.