WENDY J. DAHL¹, ISMA BENTERKI²*, STEPHANIE-ANNE GIRARD², THOMAS A. TOMPKINS²

*Correspinding author

1. Food Science and Human Nutrition Department, University of Florida,
359 FSHN Building Newell Drive, Gainesville, Florida, USA

2. Lallemand Health Solutions,
6100 avenue Royalmount, Montreal, Québec, Canada

Abstract

Physical activity is essential for the prevention of many chronic diseases. Health benefits increase with frequency and intensity of activity; however, the stress induced from over exertion can suppress the immune system and increase risk of respiratory tract infection and intestinal disturbances. This is more evident in high-endurance elite athletes, but also can be observed in people with active lifestyles. Upper respiratory tract illnesses negatively impact quality of life and impair performance of athletes undertaking intense exercise. Although medications for symptom relief may be used, they are not without side effects. Probiotics offer a safe option, as recent studies on Lactobacillus spp. demonstrate improved immune status providing protection against respiratory tract illness in athletes.

INTRODUCTION

Probiotics have been shown to modulate the immune response in a wide range of in vitro cell models and animal models (1). Furthermore, systematic review and meta-analysis have substantiated from a number of good quality randomized controlled trials that certain probiotics reduce the duration of acute respiratory tract infections in otherwise healthy children and adults. Specifically, children and adults who received probiotics including Lactobacillus and Bifidobacterium strains, experienced fewer days of illness, significantly shorter episodes of acute respiratory infections and fewer days of absenteeism from day care, school, and work than individuals receiving placebo or no treatment (2). In addition to healthy adults and children, the efficacy of probiotics in mitigating upper respiratory illness and symptoms has recently been studied in athletes.

Physical activity can have both positive and negative effects on immunity, depending on its intensity and volume. Upper respiratory illness accounts for a significant percentage of the non-injury related illnesses reported by elite athletes (3). Upper respiratory symptoms have ...