A study in the British Journal of Sports Medicine finds that the rate and length of respiratory illness in distance runners is substantially cut by the probiotic Lactobacillus. The normal immune response to colds and flu can be suppressed by heavy exercise, which can leave some athletes vulnerable to them.
Twenty elite athletes took three freeze-dried capsules twice daily of the probiotic Lactobacillus fermentum or a placebo, during four months of winter training. Lactobacillus is a lactic acid bacteria that has been used in the treatment of gut infections. Treatments lasted four weeks each, interspersed by a month of nothing, so that by the end of the period all athletes had taken both the probiotic and placebo.
Respiratory tract infections were assessed, together with treadmill performance, immune response. While there was no difference in performance between between athletes taking the probiotic and placebo, athletes taking the probiotic had less that half the number of days of symptoms of the athletes taking the placebo. Specifically, respiratory symptoms while taking Lactobacillus lasted 30 days compared with 72 days for those taking the placebo. Levels of interferon gamma were doubled by the probiotic, an important element of the body’s immune response.
"Probiotics seem to increase systemic immunity, possibly by boosting the activity of T cells", say the researchers. "The potential of this probiotic to be used as a treatment to ward off illness merits further investigation", they say.
"An improvement in resistance to common illnesses constitutes an important benefit to elite athletes undertaking high level training in preparation for national and international competitions," they conclude.
Source: British Journal of Sports Medicine (First Br J Sports Med 2008; doi 10.1136/bjsm.2007.044628)