Do Probiotics Really Work?

The Editors of Bicycling

When a battle in your belly threatens to disrupt your workout, probiotics are key to calling a truce
By Allison Young, Bicycling

What's going on in your gut can mean the difference between a good fitness day and a bad one. After all, your stomach is where you process all those nutrients that fuel your workout. When it's out of whack, your exercise or ride will suffer. (Learn how to tell whether you're on the right track with these 7 Signs Your Training is Working.)

It all comes down to microbe management. Your digestive system is home to trillions of bacteria. Some are beneficial and keep you healthy; others are the kind that can make you sick. As long as there's a balance between the good and bad, your system will function normally, says Shekhar Challa, MD, author of Probiotics for Dummies. But when that equilibrium is thrown off--thanks to anything from taking antibiotics (they kill all bacteria) to stress, age, even exercise--you start feeling lousy. You can restore a healthy balance using probiotics, or beneficial bacteria, which are found naturally in your body and in fermented foods like yogurt, kefir, and sauerkraut. Here's how probiotics can improve your health--and your workout.

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Settle Your Stomach

Heartburn, cramps, nausea, and gas are common among runners and cyclists, especially before, during, and after a race or event. By improving your digestive function, probiotics can help reduce those complaints. Introduce them to your diet slowly to allow your stomach time to adjust to the new cultures, says Jo Ann Hattner, MPH, RD, author of Gut Insight. "And start taking them at least two weeks before an event to prevent surprises, like gas and bloating," she says. Hattner also suggests consulting a physician before you start using probiotics.

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Whittle Your Waist
Researchers at the Washington University School of Medicine in St. Louis reported that people who are overweight have fewer good bacteria in their digestive systems than those who maintain a normal weight. And researchers in Japan found that taking a daily probiotic supplement may help you shed fat around your belly. If your diet and exercise regimen isn't helping you slim down, check out these 7 Surprising Reasons You're Not Losing Weight.

Fight Off Colds
Upping both your training time and your mileage can make you more vulnerable during cold and flu season. All that pedaling gets blood flowing to your heart and limbs, but diverts it from your gut, which is where 90 percent of your immune system resides. Probiotics work by crowding out the bad bacteria to form a protective barrier inside the intestine, and a study in the British Journal of Sports Medicine concluded that they enhance immune function in endurance athletes.

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Power Your Performance
Probiotics help the body make B vitamins, says Challa, which improve endurance and help process muscle-mending protein. What's more, they promote absorption of vitamins and minerals, improving your body's ability to recover from hard rides.

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