Gut Microbiome Response to Long-Haul Travel in Elite Football Players

Study Overview During the pre-season period it has become increasingly popular for professional football teams to travel to locations such as North America, Asia and Australia in attempts to maximise commercial revenue. The gut microbiome, the diverse bacterial community known to influence key physiological processes, has been shown to be negatively impacted by long-haul travel. As a result, elite athletes may benefit from dietary interventions to mitigate these negative impacts especially when considering the intense heat and physical demands of a pre-season camp conditions which have been shown to induce gut dysbiosis.

This study will firstly attempt to highlight the impact of long-haul travel on the gut microbiome of professional football players. It will also attempt to determine the efficacy of a probiotic dietary intervention in maintaining gut microbial stability in response to long-haul travel. A randomised, placebo-controlled trial will be utilised whereby players will consume either a daily probiotic or placebo. In addition, players will provide multiple faecal samples at specific time points; 1) arrival from the off-season break, 2) prior to the pre-season tour flight, 3) upon arrival to the pre-season tour destination, and 4) within five days of arriving back in UK. It is predicted that the probiotic intervention will result in greater microbial diversity and lead to a reduction in abundance of pathogenic bacterial strains typically seen following long-haul travel.

Background & Rationale The human gut microbiome is a sophisticated eco-system of microorganisms comprised of bacteria, archaea, fungi and viruses. This rich and diverse microbial community actively contributes to physiological processes such as energy metabolism, nutrient uptake and immune response. It is accepted that both the intensity and pattern of physical activity alters the composition of the gut microbiome and there is growing interest regarding the bidirectional association between exercise and the gut microbiome.

One sporting context which has seen a growing body of literature in this area is professional football. The professional football player is required to play up to 50 matches a season with regular periods of congested fixtures often played every 4 days for as long as 3 consecutive weeks. Given that the gut microbiota is heavily involved in the production and storage of energy, processes which are vital to meet the demands of physical performance, a suboptimal gut microbiota configuration may have a significant influence over players performance. As a result of the demands of the professional football player it is vital that such implications are avoided. Various authors have investigated the gut microbiome of the professional footballer across a range of study designs within both male and female cohorts. The results of these studies appear promising with findings suggesting that certain dietary strategies can maintain gut microbial stability and that elite players demonstrate higher prevalence of beneficial microbial populations compared with less active subjects.

When considering microbial stability several factors have a drastic impact on functional richness and microbial diversity. One such factor is travel, with short-term travel having been found to increase intra-individual gut microbiota fluctuations in non-athlete populations. These changes appear to be influenced by the composition of the gut microbiota prior to travel. In addition, international travel combined with dietary changes has been shown to negatively impact the gut microbiome of elite athletes, with reductions in microbial diversity and shifts in taxonomic profiles. However, to date no studies have explored the impact of long-haul travel on the gut microbiome of the professional footballer, highlighting an immediate gap in the literature.