Effects of milk fat globule membrane on gastrointestinal and immune responses to exercise

It is well established that exercise, particularly of a strenuous and/or prolonged nature, can cause perturbations to gastrointestinal (GI) integrity and immune functions. Many nutritional interventions have been researched in the context of mitigating these disturbances, of which dairy-based supplements have shown promising findings. Milk fat globule membrane (MFGM) has received considerable attention for its role in infant health, where it has demonstrated positive effects on the GI and immune systems. However, whether these results are also evident in an adult population is currently unclear, highlighting a clear gap in the research. The aims of this thesis were to investigate the short-term and long-term effects of MFGM on GI and immune functions, which was assessed across 3 randomised controlled trials. Chapter 3 (study 1) assessed the effects of short-term (2 weeks) MFGM supplementation on gut damage and permeability following a strenuous exercise bout. The results found that MFGM prevented an increase in gut epithelial cell damage and permeability following exercise. Chapter 4 (study 2) provided a mechanistic insight into the immunomodulatory effects of MFGM, investigating cellular and mucosal immune functions following prolonged cycling. It was found that MFGM enhanced resting neutrophil function and attenuated the exercise-induced depression of neutrophil function. Building on the promising findings of study 2, Chapter 5 (study 3) investigated the effects of long-term (12 weeks) MFGM supplementation on upper respiratory tract infection (URTI) incidence/burden and mucosal immune functions. Despite the promising findings from the previous two chapters, there was no effects observed on URTIs or mucosal immunity. The findings of this thesis demonstrate that MFGM may help maintain GI and immune functions in response to exercise stressors. However, this did not translate to protection against URTIs. This thesis highlights the GI and immune benefits of MFGM and the need for further research into this potential nutraceutical.