Probiotics can be incredibly beneficial for cyclists, says Dr. Ralf Jäger, who has been studying them as an inexpensive way to improve health. Probiotics, or live microorganisms that can be found in fermented foods or in pill form, help create a system of happy bacteria throughout your gut.
https://www.bicycling.com/training/a20042607/how-use-of-probiotics-benefits-cyclists/