Lactose malabsorption affects ~70% of the world adult population with consumption of milk and milk-based products in susceptible individuals often inducing gastrointestinal (GI) dysfunction compromising health. Additionally, athletes may experience (GI) symptoms exacerbated by the intensity of the exercise, jeopardizing performance and exercise recovery. Many of these athletes represent minority populations, including African Americans, who may be particularly vulnerable to nutrition-related GI issues. As African Americans contribute largely to the American Football roster, the standard, often dairy-based, recovery products provided by the athletic department may not always fit the need of a large part of the team as they may cause GI dysfunction and decrease athletic performance.

According to the current body of literature, lactose malabsorption is dictated by the amount of lactase enzyme in the small intestine, gut-transit time, and composition of gut microbiota (GM). Moreover, the ability of GM to harvest energy, affect metabolism, and influence GI health is expected to play an important role in sports performance. Therefore, there is a significant need to identify and correct the consequences of lactose malabsorption-induced GI dysfunction and composition of the GM in susceptible minority athletes.

The aim of the study is to identify the prevalence of GI dysfunction in ASU football athletes and assess the GM and lactose malabsorption of affected athletes compared to athletes not displaying symptoms.

The study will be cross-sectional where consenting ASU football athletes ≥18 years of age will first be screened for GI dysfunction by the 15-item Gastrointestinal Symptom Rating Scale (GSRS) to determine eligibility for lactose malabsorption and GM evaluation. This will occur in two phases. Phase one: Identify the prevalence of GI dysfunction in the athletes. Athletes reporting ≥1 GSRS symptom will be considered eligible for the second phase. Phase two: Assess the GM and breath hydrogen levels (lactose malabsorption test) of the symptomatic athletes compared to non-symptomatic athletes. Based on the current ASU football roster and in collaboration with the ASU athletic department, we will expect to recruit 40-50 participants.

GM analysis will be conducted on the athlete's fecal samples. Stool samples will be assessed for microbial community diversity and taxonomic frequencies following the sequencing of the 16S rRNA gene, common to all bacteria in the gut. Within a week after the stool sample collection, five breath hydrogen concentrations samples will be measured after the ingestion of a lactose load using the standard clinical methodology. In addition, a brief questionnaire reviewing the subject’s current level of GI disturbance, 24 h dietary intake recall, and physical activity questionnaire will be collected.

At the completion of this project, we will have identified lactose malabsorption and differences in the GM in high-level football players prone to GI dysfunction. Advice has been provided to football players and staff for the use of food products that can help to improve their gut microbial community, and consequently, reduce their GI discomfort. Results contribute to the continuous development of an easy and quick detection protocol for athletes who experience GI discomfort.

Last updated April 2021.