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Quinn on Nutrition: How probiotics are soldiers against illness

November 17, 2014

Who would have guessed that cowboys sitting around a campfire eating beans would be feeding their bodies’ good bacteria? In our gut (a cowboy term for "intestinal tract") we have trillions of good guys called "probiotics" — beneficial bacteria that protect us from the bad bacteria that can make us sick. Here’s how they work:

More than 1000 species of microbes live in our digestive tract. Some are beneficial and some are harmful. When the good guys outnumber the bad, we digest our food better, have less diarrhea and constipation, and are protected from infectious diseases. Some evidence even suggests that good bacteria can help us stay lean.

Probiotics don’t wear white hats but they can be identified by their distinctive titles. Common family names include Lactobacillus and Bifidobacterium — sometimes abbreviated L. and B. respectively. Species within these families include acidophilus and casei. Probiotics are further identified by distinct strains with specific actions within the body.

For example, Lactobacillus rhamnosus GG is a well-studied probiotic for digestive health found in a product called Culturelle. Bifodobacterium lactis — a probiotic found in Activia yogurt — was found to protect the lining of the intestinal tract in people with a sensitivity to gluten.

Perhaps the most studied use of probiotics is in the prevention of diarrhea due to antibiotic use. Lactobacillus GC, L.rhamnosus, and S.boulardi have been shown to be effective good guys in this arena. Dan Active — a yogurt that rounds up L. bulgaricus, S.thermophilus, and L.casei — lowered the risk for antibiotic-associated diarrhea caused by the bad germ, Clostridium difficile (aka "C.dif").

Probiotics in food run with the cultured crowd. Yogurt, buttermilk and kefir as well as fermented vegetables like kimchi and sauerkraut are home to many of these good guys. Look for products that feature "live and active cultures."

Just like rough and tough cowboys, good gut bacteria need to be fed. They thrive on fibers found in whole grains, fruit, vegetables and beans, of course. These "prebiotic" dietary fibers thus nourish the good "probiotics" that keep us well. When we eat a varied diet, we ingest a posse of these good guys to more effectively fight the bad guys.

A 2014 update on probiotics for human health from Martin Floch at Yale University lists how specific strains of probiotics have been used to prevent or control diseases of the digestive tract, especially those related to diarrhea and bowel disease. Yet we still have much to learn about which probiotics are useful for certain medical conditions.

One caution: Even though probiotics are "Generally Recognized As Safe" by the U.S. Food and Drug Administration, they should not be used willy nilly, especially in people with critical illnesses.

 

 





 



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