Nowadays it seems like they're everywhere -- in yogurt, juice and in supplement form even at mass retailers. Probiotics have been embraced by consumers and food manufacturers alike. But unlike some health/food fads, scientists also are studying the importance of the bacteria that coexist with us on our skin, in our mouths and in our intestinal tract.
These organisms compose what is known as each person's microbiome, which is crucial in breaking down and absorbing nutrients in foods and in such conditions as obesity and insulin resistance.
Dr. Pierre Brunschwig of Helios Integrated Medicine in Boulder, says probiotics can be particularly helpful for people with stomach issues such as Crohn's disease, irritable bowel syndrome and ulcerative colitis.
"(They can help) with any kind of chronic gut pain," he says. "There's a very low threshold (for recommending them)," he says. "One could make the case that everyone should be taking them."
But what should you take? Even for those with certain issues, standing in the probiotics aisle can be a confusing experience.
Part of that is because the science is so new that few strains of bacteria are available, as researchers continue to study the diversity of intestinal flora and attempt to discern which species are the most beneficial.
"We are beginning to know what we don't know," Brunschwig says. Although he adds "The last three years have seen an explosion in terms of what we understand."
Brunschwig says foods with probiotics are potentially helpful for maintaining gut health. In addition, those recommendations about eating lots of fruits and vegetables also apply, since the fiber helps feed beneficial bacteria.
However, he says that people who have chronic conditions, where the composition of bacteria may need to be changed, are likely to need higher doses of probiotics than food provide to restore balance.
He says it's best to look for a product that contains several strains of bacteria, and in general, the higher the dose, the better -- as much as 100 billion or even a trillion organisms a day if someone is trying to treat a condition such as irritable bowel syndrome. For food allergies and auto-immune disorders, which can sometimes be helped with probiotics, he recommends doses in the 80 billion to 100 billion range. Brunschwig also says that refrigerated products are more likely to have live organisms.
Cat Pantaleo, lead practitioner and a certified nutritionist and herbalist at Phamaca, says people most often seek probiotics for vaginal yeast or bacterial infections, digestive problems and post-antibiotic use.
She says the most important thing with probiotics is that they actually make it to the digestive tract.
"Bacteria are very fragile. They're subject to breaking open and dying from heat or mechanical force," she says.
She often recommends Pharmax brand, since the company does clinical studies to make sure the bacteria arrive intact.
Pantaleo adds that people should not expect immediate results.
"It takes three months to reestablish good, healthy flora in the intestinal tract," she says.
She advises people to start with a high dose for about a week and then go down to a smaller number. In addition, she says that stomach discomfort is normal for the first couple of days, but that if it continues for longer than that, a patient should decrease the dose and then build up.