The ancient Greeks knew what many consumers today are just discovering: that food can sustain health in ways well beyond meeting basic nutritional requirements. But in 400 B.C., when Hippocrates said, ?Let food be your medicine,? he probably wasn?t thinking about prebiotics and probiotics.
But Elie Metchnikoff was. The Russian researcher noted that ?Bulgarians seemed to live long,? says probiotics expert Barry Goldin, Ph.D., a professor at the Tufts University School of Medicine. ?So he described the benefits of yogurt,? a course of study that won him the Nobel Prize in 1908. Nearly a hundred years later, consumers jumping on the latest functional foods trends are just discovering the benefits that live bacteria can convey. Recent research has shown that eating foods containing certain types of live bacteria can prevent gastrointestinal disorders, yeast infections and diabetes and can support immune function (especially in children) and reduce the symptoms of lactose intolerance.
Foods such as yogurt and kefir (a fermented milk drink) are considered probiotics because they contain beneficial lactic acid bacteria that aren?t normally found in the human gut. What?s more, these bacteria—Lactobacillus acidophilus, L. bulgaricus, Streptococcus thermophilus and Bifidobacterium bifidum—are not digested in the upper GI tract, as most bacteria are, so they can help counteract the ?bad? bacteria that live in the colon and stomach and give rise to digestive problems. Common effects of an overabundance of ?bad? bacteria include diarrhea, constipation, gas, nausea and bad breath.
To be truly probiotic, however, the bacteria in yogurt and kefir must be live. The National Yogurt Association, based in McLean, Va., has developed a ?Live & Active Cultures? seal to distinguish the probiotic formulations.
Other sources of probiotics include fermented foods such as miso, tofu, tempeh, raw cheese, sauerkraut and kim chee, at least according to some experts. Fermentation is one of the world?s oldest methods of preserving food and promoting health. ?[Long ago, people] fermented these products with organisms that were maintained and passed on from generation to generation. ? It was practical for food storage,? says Goldin. But not all fermented foods are probiotic, he notes. For example, organisms added to milk may make delicious buttermilk but may not have health benefits. ?It?s not necessarily a true probiotic—it?s a food fermenter,? Goldin says.
As the benefits of probiotics become more widely known, manufacturers are adding them to a greater array of foods. ?In various parts of the world they?ve been added to all kinds of things,? says Goldin. Stonyfield Farm uses multiple organisms, in addition to the yogurt?s starter culture. Sweet milk, an unfermented milk with probiotics added, is popular in Europe, as are cheeses, juices, whey drinks and sports drinks with added microbes, he says. ?Obviously it can?t be put into some food that?s going to be cooked because that will kill the organism.?
If the taste of probiotic-containing foods is objectionable, probiotic supplements are also widely available in both capsule and tablet form. Europeans also have the option of sachets containing powdered probiotics. ?You can sprinkle it on your breakfast cereal if you want to,? Goldin says, although the powdered form has a shorter shelf life—?days to weeks,? he says. But some capsules are hermetically sealed and can remain potent for up to a year at room temperature. ConAgra?s Culturelle capsules contain Lactobacillus GG, which is one of the most highly researched strains of lactic acid bacteria.
Goldin cautions those taking a probiotic supplement to take it with food. ?Don?t take it on an empty stomach because of the acidity. If you have it in a milk-based food, the pH of the stomach is more moderate.? As for dosage, Goldin says ?Most people feel that you [must] get between 1 billion and 10 billion bacteria to be effective, on a daily basis. That would translate into about 4 to 5 ounces [of yogurt] every day, if the level of bacteria is high.?
Not all products with beneficial bugs label the amount of bacteria per serving, but a movement is underfoot to require such labels. Most brands have 200 million to 300 million per cup, according to usprobiotics.org. Dannon?s DanActive (formerly Actimel) is among the highest, with 10 billion bacteria per serving.
To encourage the growth of probiotic flora in the gut, many people are looking toward prebiotics, the easily fermented, soluble fibers that probiotics feed on. And, according to recent research, prebiotics may prevent diabetes and osteoporosis, among other ills. Research conducted in 2003 shows consumption of probiotics and prebiotics may even prevent the development or spread of colon cancer, though Goldin says there?s not yet enough evidence to support that claim.
The most commonly available prebiotics are fructo-oligosaccharides. FOS are chains of fructose molecules and are inherent in Jerusalem artichokes, onions, leeks, garlic, honey, bananas and some grains. Manufacturers are beginning to introduce FOS into yogurts, giving consumers their probiotics and prebiotics in one product. According to Frost & Sullivan, a San Antonio-based research group, the prebiotics market totaled $15 million in 2003 and should hit $103.2 million by 2010.
Manufacturers also are adding prebiotics to sweeteners such as Wisdom Natural Brands? SweetLeaf SteviaPlus, which has added inulin, as well as to baked goods, nutrition bars and meal replacement shakes. Lactose-sucrose, lactilol, isomalto-oligosaccharides and inulin are other types of prebiotics. Isomalto-oligosaccharides are marketed in Japan as dietary supplements and in functional foods, but they are considered experimental in the United States. Obviously, people with lactose intolerance should avoid lactose-sucrose, as well as lactilol.
Experts suggest starting a prebiotics regimen with 1-2 grams per day, and gradually building up to 4 grams or more per day.
Know your niche
But probiotics and prebiotics aren?t necessarily for everyone. ?Typically what we look at are people with digestive problems, or who have been exposed to a lot of antibiotics, whether they?re experiencing digestive problems or not, just because we know their gut flora has been wiped out,? says Jennifer Lovejoy, chairwoman of the Bastyr University nutrition department.
People traveling abroad may minimize their risk of diarrhea if they include probiotics in their diet, Goldin says. He says pregnant or nursing women, children and ?infants who have a high likelihood of developing food allergies or asthma? may want to consider probiotics as well.
Another Bastyr prof concurs. ?In terms of evidence, the clearest has been in people with autoimmune stuff, primarily atopic dermatitis. ? There?s [also] some evidence about asthma prevention in kids,? says Petra Eichelsdoerfer, R.Ph., N.D., an adjunct faculty member at the holistic-health college in Seattle. Eichelsdoerfer teaches a class on dietary supplements and recently completed a research thesis in probiotics.
As for the claim that beneficial microbes can prevent or treat cancer, Goldin and Eichelsdoerfer agree here, as well: ?It may be a leap of logic,? says Eichelsdoerfer, allowing, however, that a good portion of cancer is autoimmune-mediated, so a connection is possible.
And while muscle magazines tout the benefits of probiotics and prebiotics—?The bodybuilder can also benefit, as he/she can digest their (large quantity) of food more easily, helping to provide a more efficient influx of energy and protein,? claims Muscle Talk, a British online publication—Eichelsdoerfer finds that a stretch. ?Most of the probiotics—the activity is going to be in the colon, and by the colon most of the absorption has occurred.? The only exception, she says, is that fermented foods may help with lactose digestion. ?A lot of bodybuilders do a lot of milk products,? she says.
Eichelsdoerfer is positive about one thing, however: ?Research in probiotics is skyrocketing.? And that should bring even more clarity into the ongoing discussion of the benefits of bacteria.
Natural Foods Merchandiser volume XXV/number 7/p. 14, 17