According to a recent study published in the British Journal of Sports Medicine, professional long distance runners who ingested the probiotic Lactobacillus had shorter and less severe spells of respiratory illness than those who ingested a placebo.
The Australian researchers first note that “some endurance athletes undergoing strenuous training have an increased susceptibility to upper respiratory tract infection (URTI).” Exercise can subdue normal immune response, leaving athletes more vulnerable to respiratory viruses, such as colds and flu.
The study participants consisted of 20 elite, endurance athletes who were undergoing four months of intensive winter training. The athletes ingested either three freeze-dried capsules twice daily of the probiotic Lactobacillus fermentum or a dummy capsule (placebo).
A probiotic is a dietary supplement containing potentially beneficial bacteria or yeasts. Lactobacillus is a type of lactic acid bacteria, a class of bacteria that has been shown to be successful in treating infections of the gut.
The study was conducted using a double-blind, placebo-controlled, crossover design. Supplement (or placebo) administration lasted 28 days followed by a month-long washout period and then placebo (or supplement) administration for another 28 days. This design allowed each of the athletes to take the probiotic for one month and the placebo for one month, without any effects of one influencing the effects of the other.
During the study period, researchers assessed treadmill performance, immune response, and the length and severity of respiratory tract infections.
Compared to those taking the placebo, consumers of the probiotic did not exhibit any difference in running performance.
Half as many upper respiratory tract infections and lower respiratory illness episodes were reported during the probiotic treatment compared with the placebo period. The average episode duration did not differ between Lactobacillus (7.5 days) and placebo (8 days) treatments. However, the total number of total illness days while taking the probiotic was significantly less than during placebo treatment – 30 days compared with 72 days. The severity of symptoms also tended to be milder during the probiotic period.
The researchers measured a doubling of interferon gamma levels in the probiotic treatment group, an important component of the body’s immune response. The increase in systematic immunity was possibly linked to a boosting of activity in T cells – white blood cells that play a central role in the body’s immune system.
The authors call for more research to assess the potential of this probiotic to be used as a treatment to ward off illness. “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,” conclude the authors.
Oral administration of the probiotic Lactobacillus fermentum VR1-003 and mucosal immunity in endurance athletes
Amanda J Cox, David B Pyne, Philo U Saunders, and Peter Allen Fricker
British Journal of Sports Medicine. (2008)
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Written by: Peter M Crosta