Harry Jarrett

Dr. Harry Jarrett

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Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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21 August 2024 in Nutrients
Verified
Journal Article
Open access
PDF file
MGMarlies Govaert
Marlies Govaert
CRChloë Rotsaert
Chloë Rotsaert
CVChelsea Vannieuwenhuyse
Chelsea Vannieuwenhuyse
CDCindy Duysburgh
Cindy Duysburgh
SMSophie Medlin
Sophie Medlin
HJHarry Jarrett
Harry Jarrett
Many health-promoting effects have been attributed to the intake of probiotic cells. However, it is important that probiotic cells arrive at the site of their activity in a viable state in order to exert their beneficial effects. Careful selection of the appropriate probiotic formulation is therefore required as mainly the type of probiotic species/strain and the administration strategy may affect survival of the probiotic cells during the upper gastrointestinal (GIT) passage. Therefore, the current study implemented Simulator of the Human Microbial Ecosystem (SHIME®) technology to investigate the efficacy of different commercially available probiotic formulations on the survival and culturability of probiotic bacteria during upper GIT passage. Moreover, Colon-on-a-Plate (CoaP™) technology was applied to assess the effect of the surviving probiotic bacteria on the gut microbial community (activity and composition) of three human donors. Significantly greater survival and culturability rates were reported for the delayed-release capsule formulation (>50%) as compared to the powder, liquid, and standard capsule formulations (<1%) (p < 0.05), indicating that the delayed-release capsule was most efficacious in delivering live bacteria cells. Indeed, administration of the delayed-release capsule probiotic digest resulted in enhanced production of SCFAs and shifted gut microbial community composition towards beneficial bacterial species. These results thus indicate that careful selection of the appropriate probiotic formulation and administration strategy is crucial to deliver probiotic cells in a viable state at the site of their activity (distal ileum and colon).

14 February 2025 in Nutrients
Verified
Journal Article
Open access
PDF file
HJHarry Jarrett
Harry Jarrett
SMSophie Medlin
Sophie Medlin
JMJames Cameron Morehen
James Cameron Morehen
Background/Objectives: Gut microbiome modulation through probiotics is a growing area of research, with several investigations reporting beneficial health outcomes for the host. Physical exercise has been shown to impact gut microbiome diversity. Emerging evidence suggests that probiotic supplementation can affect exercise performance. However, the mechanisms and domain-specific effects of gut microbiome modulation on performance remain to be elucidated. This narrative review aims to investigate the potential mechanisms underpinning the ergogenic benefits of probiotics and further define the current evidence base for specific performance domains. Discussion: The literature suggests that improved recovery after intense training regimes, enhanced nutrient absorption, alleviation of gastrointestinal symptoms, and improved immune function may underpin the beneficial effects of probiotics on sporting performance. A small number of trials also suggest that probiotic supplementation may improve symptoms of performance anxiety. However, further research is warranted on this topic. The evidence is most substantial for improvements in endurance performance, whilst only a few trials have investigated the impact upon power performance, albeit with promising results. Conclusions/Future Perspectives: In summary, probiotic supplementation has been shown to improve sporting performance; future research may wish to further explore the impact on power performance and investigate specific mechanisms of action.

30 December 2024
Verified
Conference Paper
Closed access
HJHarry Jarrett
Harry Jarrett
RMRyan McNally
Ryan McNally
SMSophie Medlin
Sophie Medlin
BFBushra Farukh
Bushra Farukh
LHLisa Holton
Lisa Holton
ASAgata Sobczyńska-Malefora
Agata Sobczyńska-Malefora
Introduction Mental health disorders including depression and anxiety are major contributors to global disease burden. Evidence indicates that nu | POSTER