By Sally Squires
Tuesday, April 15, 2008
How about having some bugs with your breakfast cereal?
That's the idea behind the growing nutritional trend of eating food with probiotics -- friendly bacterial strains that may help thwart an array of conditions from allergies, asthma and eczema to gastrointestinal ailments.
The potential for probiotics is huge, since their use seems to have virtually no side effects. Exploiting friendly microbes also fits with the trend to promote health and treat conditions with fewer prescription medications.
So it should be no surprise to see probiotics turning up in breakfast cereals, yogurt, beverages and cheese. (See the box at right.) And they're not just relegated to the dusty corners of health food aisles. Kraft, Post, Dannon and Kashi are among the mainstream companies selling probiotic products. Dannon is even using the teenage sensation Miley Cyrus (a.k.a. Hannah Montana) to help market one of its probiotic lines -- Danimals -- to your kids.
Probiotics seem to work by changing the mix of bacteria that already colonize our bodies. In the gastrointestinal tract, having more healthy bacteria can help squeeze out unfriendly microbes. Probiotics have shown some potential in thwarting the food-borne infections such as salmonella and E. coli. They seem to be effective in helping to treat rotavirus, which strikes infants and children, and they show promise against C. difficile, a gastrointestinal infection that often hits the elderly in assisted living and nursing homes. Probiotics appear to help ease irregularity and can prevent the diarrhea that often occurs with antibiotic use.
The friendly bacteria in probiotics also appear to help to dampen overactive immune systems that result in allergies, asthma and other autoimmune conditions.
For example, consider some new Finnish findings from a study in which infants with a family history of allergies were given probiotics: At age 2, these children were less likely to develop eczema, an itchy chronic skin condition, than their counterparts who didn't receive probiotics.
Probiotics could also boost overall health. In one recent German study, researchers found that regular consumption of probiotics cut the duration of the common cold by two days and lessened symptoms when colds occurred. A handful of studies have shown that healthy adults and children who took probiotics had fewer school and work absences than their counterparts who didn't.
"It's real interesting," notes microbiologist Mary Ellen Sanders, executive director of the International Scientific Association for Probiotics and Prebiotics.
Even so, Sanders and others probing probiotics say there still isn't enough positive evidence to support their widespread use. "I would not want to offer any false hope," says Bob Rastall, head of the department of food bioscience at Britain's University of Reading. "We still need to do more work."
That's because scientists still can't agree on an exact definition of probiotics. Some say that probiotics include any food, such as yogurt or kefir, with live cultures of friendly bacteria. But the microbes in those products don't always survive transit through the acid-filled stomach. So other scientists say that a true probiotic must contain enough hearty cultures to survive and produce measurable health effects.
"There are a lot of products calling themselves probiotic foods, but we don't know if they have efficacious levels" of bacteria, Sanders says. It's difficult for consumers to know what to choose, she says, "because there's no stamp of approval where these things have been evaluated by independent third parties."
Still unproven are which strains of friendly bacteria are best to use for what purposes. There's little knowledge of the optimal doses for effectiveness, and there's uncertainty about the best way to deliver probiotics. Should they be given in dietary supplements -- the method used by many studies -- or added to food?
Even Sanders says she often struggles to determine what strains and amounts of probiotics are in various foods and other products.
So what does she do? She checks the company Web sites for information. And if they don't provide what she is looking for, she calls the company.
"It's very easy to say that all probiotics will work," Sanders says. "But they won't all work, and it is a detriment to the industry as a whole to say that there is this sort of generic approach that any product [with probiotics] will do anything."
But if you and your family enjoy the growing array of foods that contain live cultures, that's another story. "I would be perfectly happy to feed my kids probiotics," says Rastall, who often serves them to his children. "And I do eat them myself."