We hear about them everywhere -- how they clear up everything from a bloated gut to a depressed mind. How they boost the immune system and improve skin health. How they delay allergies in children and prevent urinary tract infections in women. The list is truly impressive. But what are probiotics? And do they deserve all the attention and accolades?
"Probiotics can impact just about everything in the body," says Meagan McCusker, a University of Connecticut dermatologist who uses probiotics to treat a wide variety of conditions including acne and psoriasis. "They really can't and shouldn't be overlooked when it comes to overall health maintenance."
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So what, exactly, are they?
By way of the National Institutes of Health: "Probiotics are live microorganisms that are similar to beneficial microorganisms found in the human gut. They are also called 'friendly bacteria' or 'good bacteria.' "
The idea is that the "friendly bacteria" will help fight the good fight along with gut-dwelling bacteria to scare off pathogens, improve immune function and aid digestion, among other things, McCusker says.
"In some patients I have seen rapid improvement of digestive distress like gas and bloating after they have started taking probiotics," says local nutritionist Jared Rice, who started taking the supplement for his own health maintenance seven or eight years ago.
"I can definitely say that it's been a very positive experience for me since I started taking probiotics. And I have never experienced any downsides," he says.
It was around that time, in 2006, that Dannon introduced its Activia yogurt with live cultures to the U.S. market. That's when many Americans picked up on probiotics, says 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 says.
Probiotics come in many forms, and they don't need to be delivered through yogurt -- particularly important for the dairy-intolerant. Probiotics can be found as fresh, refrigerated supplements at some health food stores, as well as dried and preserved.
For health maintenance, McCusker says, try starting with no more than 5 billion units of active probiotic cultures -- preferably a mix of cultures that include strains of Lactobacillius and Bifidobacterium.
Ebeth Johnson, a Washington nutritionist and chef, says to look for the following foods to provide that probiotic benefit: 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 says. "Get them at your local health food store and blend them into your morning fruit and greens smoothie."
Rice cautions 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.
On the other hand, if you take probiotics as a supplement, don't look at that as a silver bullet, because benefits will be experienced only if the probiotic is combined with a healthful diet on the whole, he says. "You can't continue to eat fast food and pop some probiotic supplements and expect a great outcome."
In fact, the 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 gut environment.
The appropriate probiotic dosage, according to McCusker, is about 5 billion units for daily health maintenance and 15 billion-20 billion when you are treating a specific condition. (Note: The Food and Drug Administration has not approved any health claims for probiotics.)
Before you get to the higher dosages, Rice says, you should talk with a nutritionist or doctor with particular expertise in the area of probiotics about side effects, though they are rare.
So, is this all a fad that will disappear once the next nutrition celebrity makes a splash?
Sanders doesn't think so.
"Unlike multivitamins, for example, many people who take probiotics actually feel much better," she says, adding that's enough of a reason for many to keep taking them.
Rice says he's excited about the therapeutic possibilities for probiotics in the future as nutritionists and doctors get a better handle on targeting certain conditions with certain strains and combinations of probiotics.
"It's an evolving topic. But I can see how probiotics at some point will be used more like a prescription," he says. "I don't think the concept of bacterial balance will fade. I think it will grow."