Strategies to enhance immune function for marathon runners : what can be done?
Level 5 - mechanism / opinion, no new human data
Narrative review without systematic methodology or primary human data pooling
PubMed 17465623 · doi:10.2165/00007256-200737040-00037
What was done
This paper reviewed literature on nutritional interventions intended to counteract exercise-induced immune suppression (the 'open window' hypothesis) and reduce the risk of upper respiratory tract infections (URTIs) in marathon runners. The review specifically examined the evidence for glutamine, vitamin C, bovine colostrum, and glucose supplementation.
What was found
The abstract reports no numerical data or effect sizes. It notes that although some evaluated supplements can alter physiological and immune changes associated with marathon running, none have consistently been shown to lower URTI risk. As a result, the authors state none can be recommended for immune enhancement in marathon runners.
Why it matters
This review highlights that physiological or immune cell biomarker changes from supplementation do not reliably translate into clinical protection against post-race infections.
Limits
The abstract provides no sample sizes, effect estimates, or details on search criteria. As a narrative review rather than a systematic review or primary trial, it represents mechanism-based reasoning and expert overview subject to study selection bias.
Cited by
- contradicts Glutamine supplementation reduces the incidence of respiratory illness in endurance athletes.