Streptococcus thermophilus is a species of probiotic bacteria commonly used in the production of yogurt. For certain individuals who are normally unable to digest lactose, Streptococcus thermophilus, which produces lactic acid to break down the milk sugar lactose, can help improve digestion when present in dairy products. Probiotics are beneficial bacteria that help maintain the health of the intestinal tract.*
In a randomized, double-blind, placebo controlled, crossover trial, 15 healthy resistance-trained men ingested daily for three weeks a placebo or an encapsulated probiotic supplement containing Streptococcus thermophilus and Bifidobacterium breve (5 billion live cells each) prior to muscle-damaging exercise. Isometric strength, muscle soreness, range of motion and girth, and blood interleukin-6 (IL-6) and creatine kinase (CK) concentrations were measured from pre- to 72 h post-exercise. Probiotic supplementation resulted in an overall decrease in circulating IL-6, which was sustained up to 48 h post-exercise. In addition, probiotic supplementation likely enhanced isometric average peak torque production at 24 to 72 h into the post-exercise recovery period and likely moderately increased resting arm angle at 24 and 48 h post-exercise, but effects on soreness and flexed arm angle and CK were unclear1.