Probiotics give endurance athletes' immune boost: study

A daily probiotic capsule was found to enhance the activity of T cells, key players in the immune system, report the researchers after following 20 elite, endurance athletes during four months of intensive winter training. "In combination with the recent report that​ L rhamonasus supplementation reduced the duration of gastrointestinal symptoms in marathon runners in the 2 weeks after the race​ [Int J Sport Nutr Exer Metab, 2007, Vol. 17, pp. 352-363], our findings point to the potential benefits of this form of nutritional intervention,"​ wrote the authors led by David Pyne from the Australian Institute of Sport. The study is published online ahead of print in the British Journal of Sports Medicine​. Consumers are increasingly aware of the health benefits associated with probiotics, including improved intestinal health and immune system stimulation. Indeed, probiotics remains a major growth market. The European sector is set to more than triple in value over the next few years, according to Frost & Sullivan, to reach $137.9 million (€118.5m) in 2010. The new study adds to the body of science by reporting that the 'friendly' bacteria may also produce benefits in endurance athletes undergoing strenuous training, previously reported to be more susceptible to upper respiratory tract infection (URTI) linked to the role of strenuous exercise in suppressing the immune system. Pyne and co-workers recruited the athletes and randomly assigned them to receive either a daily probiotic supplement containing Lactobacillus fermentum​ or placebo. After 28 days of receiving either the probiotic or placebo, they received nothing for one month (washout period) before crossing over to the other intervention. By the end of the study all the athletes had each had the probiotic and placebo formulations. Athletic performance of the subjects was assessed using a treadmill, while blood samples were taken at regular intervals to measure the immune response. The length and severity of respiratory tract infections were recorded by the subjects themselves. The researchers report no difference in running performance as a result of placebo or probiotics supplementation. On the other hand, the number of days of symptoms of URTI was halved when the athletes took the probiotic, compared to placebo. Specifically, symptoms of URTI's lasted 30 days when receiving the Lactobacillus supplements, compared to 72 days while taking the placebo. The severity of the symptoms was also less when receiving probiotics, stated the researchers. The blood samples showed that blood levels of interferon gamma, an important component of the body's immune response, were doubled when the subjects received probiotics, compared to placebo. However, no significant differences were observed in levels of immunoglobulin A and immunoglobulin A1 in the saliva, or levels of interleukin (IL)4 and IL12. Pyne and co-workers report that the benefits appear to be mediated via an enhancement of the functioning T-lymphocyte function. They do state, however, that the specific mechanism remains unclear and that it was not possible to draw definitive conclusions from the findings of the current study. "Further investigations are required to determine whether the beneficial effects of probiotic administration can translate to both the general public and specialised populations like elite athletes, clinical conditions, immuno-compromised subjects, and military and industrial settings,"​ wrote Pyne and co-workers. "The finding of clinical benefits with probiotic supplementation in a small cohort of physically fit subjects, provides the basis for further studies examining the beneficial effects of​ L fermentum VRI-003 administration on immune function in both the general community and specific populations,"​ they concluded. Source: British Journal of Sports Medicine​ Published online ahead of print, doi 10.1136/bjsm.2007.044628 "Oral administration of the probiotic​ Lactobacillus fermentum VR1-003 and mucosal immunity in endurance athletes" ​Authors: A.J. Cox, D.B. Pyne, P.U. Saunders, P.A. Fricker