Support Grows for Healthy Bacteria
Urogenital Health: Women have long eaten yogurt as a natural way to prevent yeast infections, and recent research supports this folk remedy. Scientists have linked probiotic consumption to reduced numbers of yeast infections, and studies have shown that, at least in a petri dish, probiotic bacteria can inhibit the growth of yeasts like Candida, which commonly cause infections. Still, probiotics might work even better if women put the bacteria directly where they're needed. A recent study showed that a vaginal suppository containing two types of Lactobacillus bacteria that normally live in the gut can restore the balance of bacteria in the vagina, curing a yeast infection. Other promising studies have shown that regular consumption of probiotics might help prevent recurrent urinary tract infections in women.
Cancer? Ulcers? Teeth? Recent studies have shown that probiotics might aid a number of other conditions. One study indicated that probiotics can help fight Helicobacter pylori, the bug that causes stomach ulcers and gastric cancer. A series of animal studies has shown that probiotics could help prevent colon cancer, too. And some evidence points to probiotics potentially benefiting oral health. However, many experts are unconvinced. Gorbach says that while a few of the claims are promising, solid clinical trials are needed.
The health benefits sound great, but choosing which probiotics to include in a diet can be tricky. A wide variety of bacteria get touted as probiotics, but only some of them have proven health benefits. Experts recommend looking for a product that lists genus and species, rather than a vague term like "proprietary formula." Some bacteria species in the Lactobacillus and Bifidobacterium groups have been well studied, although each has a number of strains, and not all of them have been studied.
Another problem particular to packaged probiotic supplements is that the bacteria might die or degrade while the product sits on the shelf. Most probiotic supplements should be stored in the refrigerator and used promptly once opened, says Gorbach. "As soon as you crack that bottle, the organism will begin to deteriorate." Of several million friendly bacteria in a probiotic pill, he explains, only a few thousands or hundreds might be alive and active by the time you take it.
If aiming to get probiotics through foods, look for a seal that says, "live active cultures," says Lori Hoolihan, a nutrition research specialist with the Dairy Council of California. Hoolihan notes that probiotic foods like yogurt—and certain other products, including aged cheeses and the dairy drink called kefir—generally contain the added nutritional benefits of nutrients such as calcium, vitamin D, and prebiotics, a class of molecules that she calls "food for the probiotics."
In any case, eating live probiotics doesn't guarantee that they'll reach your intestines. Bill Costerton, professor of dentistry at the University of Southern California, is skeptical that probiotics could penetrate the intestines' defense system. "The gut is lined by a great big wall of mucus," he explains. The community of bacteria that exists in a normal digestive tract, he adds, "is pretty much bulletproof." However, he agrees with other experts that taking probiotics to aid a disturbed digestive system—such as one ravaged by antibiotic treatment—is probably effective.
But nutritionist Katherine Tallmadge cautions that it might be premature to start popping probiotic supplements, noting that some products have been associated with negative side effects, particularly in people with compromised immune systems. "I don't feel comfortable recommending them to clients just yet," says Tallmadge. "There's a lot we don't know about how they work." However, she says, foods that naturally contain probiotics, like yogurt, are probably a safe bet.
Probiotic treatment should not be seen as a substitute for medical care. Rather, experts say, the major benefit of probiotics is preventive. As Hoolihan likes to say, "A few million probiotics a day keep the doctor away."