Effect of a Probiotic Intake on Oxidant and Antioxidant Parameters in Plasma of Athletes During Intense Exercise Training

Martarelli D, Verdenelli MC, Scuri S, Cocchioni M, Silvi S, Cecchini C, Pompei P.
Curr Microbiol. 2011 Mar 12. [Epub ahead of print]

In recent years probiotics (microorganisms that can provide health benefits) have received a lot of attention thanks in part to several companies advertising products with probiotics (for example, think of recent yogurt advertisements). These products are often touted for their gastrointestinal and immunological benefits. Research has indicated that some strains may also stimulate antioxidant activity by promoting antioxidant enzymes and reducing inflammation-derived oxidative stress. To determine if probiotics may be effective supplements for athletes the authors evaluated the effect of two probiotics (Lactobacillus rhamnosus and Lactobacillus paracasei; taken together) on oxidative stress in male amateur cyclists during a 4-week period of intense physical activity. This study was a retrospective analysis evaluating 24 cyclists that were randomly assigned to a control group or probiotic group. After 4 weeks of training, there were no differences in reactive oxygen metabolites (a sign of oxidative stress) between groups. However, further analyses revealed that only the control group had significantly higher levels of reactive oxygen metabolites after exercise when compared to baseline. Furthermore, the probiotic group had increased plasma antioxidant levels after training than the controls.

The authors propose that athletes may benefit from the ability of these probiotics to increase antioxidant levels and control the effect of oxidative stress. This is an interesting first step but definitely not enough for us to promote the use of probiotics among athletes. Randomized clinical trials specifically designed to test probiotics among athletes will be needed to indicate whether probiotics warrant changes in our recommendations. Furthermore, various strains of probiotics are available and we will need to gain a better understanding of which strains infer the greatest benefits. Regardless, studies like these will likely gain in the sports community. We should acknowledge that preliminary findings for specific types of probiotics have been positive but that we don’t know if this will hold up with more research. Over the years, many of us have witnessed passing nutritional fads and then watched them not hold up under further scrutiny.  It’s impossible to say if this will be another case of that but probiotics seems to be something that we will need to monitor over the next few years.

Written by: Jeffrey Driban
Reviewed by:  Stephen Thomas