Probiotics primer: What these 'good bacteria' are, what they may do

  • Article by: Gabriella Boston
  • Washington Post
  • October 22, 2013 - 4:25 PM

We hear about them frequently, how they clear up everything from a bloated gut to a depressed mind. How they boost the immune system, improve skin, delay allergies in children and prevent urinary tract infections in women.

Sounds impressive. But just what are probiotics? And do they deserve all the accolades?

Probiotics are live micro-organisms that are similar to beneficial micro-organisms found in the human gut, according to the National Institutes of Health.

Those who use probiotics, also called “friendly bacteria” or “good bacteria,” say that they, along with gut-dwelling bacteria, help fight off pathogens, improve immune function and aid digestion.

“Probiotics can impact just about everything in the body,” says Dr. Meagan McCusker, a University of Connecticut dermatologist who uses probiotics to treat a wide variety of conditions, including acne and psoriasis.

Most Americans first started hearing about probiotics in 2006, when Dannon introduced its Activia yogurt with live cultures to the U.S. market, said Mary Ellen Sanders, executive director of the International Scientific Association for Probiotics and Prebiotics.

“We’ve been tracking this topic for more than 20 years, and it really was doing nothing until Activia. And now it’s super hot,” Sanders said.

Probiotics come in many forms, not just through yogurt. They can be found as fresh, refrigerated supplements at some health food stores, as well as dried and preserved.

Ebeth Johnson, a Washington, D.C., nutritionist and chef, said some foods also provide that probiotic benefit, including unpasteurized miso, live cultured pickles, tempeh, unsweetened kefir and yogurt, as well as kombucha teas.

“Blue algae is also a great source of probiotics,” Johnson said. “Get them at your local health food store and blend them into your morning fruit and greens smoothie.”

For health maintenance, McCusker suggests starting with no more than 5 billion units of active probiotic cultures, preferably a mix of cultures that include strains of lactobacillius and bifidobacterium. He recommends 15 billion to 20 billion units when treating a specific condition.

Jared Rice, a nutritionist in the Washington, D.C., area, said you should talk with a nutritionist or doctor before taking a higher dose. (The Food and Drug Administration has not approved any health claims for probiotics.)

He also says that when buying probiotic food products you should check nutrition labels, just as you would with any food, to be sure they are healthful beyond their probiotic content and don’t have too much sugar or fat.

While they can be beneficial, probiotic supplements aren’t a silver bullet, cautioned Rice. “You can’t continue to eat fast food and pop some probiotic supplements and expect a great outcome.”

In fact, probiotics thrive best when prebiotics are present. Prebiotics, which are found in such foods as whole grains, bananas and onions, are nondigestible carbohydrates that create a probiotic-friendly environment in the gut.

So, is this all a fad that will disappear once the next nutrition celebrity makes a splash?

Rice, for one, doesn’t think so. He’s excited about the therapeutic possibilities for probiotics, as nutritionists and doctors explore targeting certain conditions with certain strains and combinations of probiotics. “I don’t think the concept of bacterial balance will fade,” he said. “I think it will grow.”

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