As if having newborn twins wasn’t challenging enough, early on Meghan Hunter found herself dealing with a whole lot of vomit. Starting when she was around three weeks old and lasting past her first birthday, her daughter had trouble keeping anything down.

“It was horrible,” Hunter tells the Georgia Straight by phone. “I would be covered in vomit at least once a week. At one point, she threw up every day, five to 10 times a day.”¦It was so stressful.”

The infant was diagnosed with acid reflux. Hunter and her husband, both teachers, tried everything their doctor suggested, from giving their daughter a medication that reduces stomach acid to simply letting her cry it out.

Nothing helped. And when she started losing weight at around a year old, her parents felt desperate. On the recommendation of a friend who runs a daycare, Hunter went to a health-food store and bought probiotic supplements.

Her daughter, now almost two, hasn’t thrown up since.

“It really was a miracle,” Hunter says. “Now she goes to bed singing as opposed to crying.”

Also known as “friendly” or “good” bacteria, probiotics are microorganisms that live in the human gastrointestinal tract. Taken in appropriate quantities through food (such as yogurt or tempeh) or supplements (in capsule, tablet, or powder form), they can, according to Health Canada, prevent and treat certain medical conditions by balancing intestinal flora.

Probiotic supplements are growing in popularity. Spending on them in the United States nearly tripled between 1994 and 2003, according to the National Center for Complementary and Alternative Medicine (NCCAM), a branch of the U.S. National Institutes of Health.

Vancouver naturopathic doctor Stephanie Peltz expects the trend to continue.

“I use probiotics widely in my practice,” Peltz says on the line from Sage Clinic, where she works. “They’re not necessarily for every single person, but they can have a beneficial effect when taken appropriately in the right dose.”

Crucial to the development of the immune system, friendly bacteria aid in the digestion of food and absorption of nutrients. They also help protect against disease-causing microorganisms, or “bad” bacteria, as well as fungi, yeasts, and parasites.

Probiotic supplements can be used to treat a range of ailments, from urinary tract infections, vaginal yeast infections, and irritable bowel syndrome to diarrhea, atopic eczema, and rheumatoid arthritis. But the bulk of the scientific evidence supporting their positive effects relates to their use in improving the overall health of the gastrointestinal tract and enhancing immune function.

As Health Canada points out, about 60 percent of the body’s immune cells are situated in the intestinal mucosa.

“If someone gets a lot of colds and flu, we would look at boosting their immune system, and that would include boosting and optimizing their digestive health,” Peltz explains.

Side effects of using supplements, such as gas and bloating, are rare, Peltz says, and tend to be mild and short-lived.

Despite the increasing public interest in probiotics, more scientific study into their safety is needed, the NCCAM states on its Web site. In particular, there is a lack of research in the form of large, carefully designed clinical trials examining how safe they are in children, the elderly, and people with compromised immune systems.

Peltz says that although many of her patients have benefited from probiotics, consumers are wise to make educated choices about using them.

“There’s lots of misinformation out there,” she says. “You can’t trust everything you hear on commercials.”

The microorganisms in probiotics are measured in colony-forming units, or CFUs. Different probiotics are effective at different levels. A product’s CFU amount should be the same as that shown to be effective in clinical studies. Research has shown health benefits from the daily intake of products ranging from 50 million CFU to more than 1 trillion.

“More CFUs does not necessarily mean better,” Peltz explains. “Poor-quality products—if the bacteria are, in fact, dead—can upset the gastrointestinal tract. Good-quality probiotics will be found in a fridge and should be stored in a fridge. Not all supplements are made alike.”¦Make sure what it says on the label has been backed up by clinical trials....People need to do their homework.”

Peltz adds that a good supplement will list the types of bacteria it contains. Most often, the bacteria in probiotic supplements come from two groups, Lactobacillus and Bifidobacterium, each of which has its own species, such as Lactobacillus acidophilus and Bifidobacterium bifidum, and strains.

The label should also state appropriate doses and provide corporate contact information. It’s a good idea to check the manufacturer’s Web site and look for the results of clinical studies, which should be published in reputable, peer-reviewed journals.

The NCCAM notes that scientists are investigating what happens to probiotic bacteria when they’re added to food, and whether their ability to survive, grow, and have a therapeutic effect is altered. (Labels must not make false, misleading, or deceptive claims about the benefits of foods that contain probiotics, according to Health Canada.)

Researchers are also looking at the ways probiotics can be used to prevent and treat a variety of health conditions. There’s conflicting evidence, for instance, on whether they can reduce cholesterol levels.

Probiotics also have a potential use in combating antibiotic-resistant bacteria in the gastrointestinal tract.