Two of the "good bacteria" used in some yogurts can protect children from catching or spreading diarrhea -- a common childhood ailment in the United States and a major killer in the Third World, doctors said yesterday.
Pediatric researchers at the Johns Hopkins Children's Center found that children given a regular diet of infant formula laced with bifida and thermophilus, the live cultures, were 78 percent less likely to get the disease than youngsters who drank plain formula.
Dr. Robert H. Yolken, director of pediatric infectious diseases, said the live bacteria are sold as supplements in health food stores but are also present in some cultured milk products including yogurt and acidophilus milk -- a product geared for people who cannot digest ordinary milk.
"We might be able to put [the bacteria] into milk delivered to schools and day-care centers," Dr. Yolken said. "We might find ways to use them overseas, or find them beneficial to adults as well as children."
He cautioned, however, that further research is needed to determine who should take the bacteria, how much they should take and which bacteria are best.
Nonetheless, it appears that parents can hardly go wrong in feeding yogurt to children who have advanced beyond breast milk or formula. Dr. Jose Saavedra, a pediatric gastroenterologist, said yogurt is a good source of calories, protein and important minerals such as calcium and is easy to digest.
"We have no concerns regarding safety and no concerns regarding the nutritional progress of the children" fed yogurt, he said.
Dr. Yolken said yogurt can serve as an excellent bridge between breast milk or formula, which children often give up in the second six months of life, and plain cow's milk, which is difficult for many children to digest.
For 17 months, researchers studied 55 children between the ages of five and 24 months who were admitted to the Mount Washington Pediatric Health System in Baltimore. The children were admitted with other ailments, but were studied because hospitals are places where youngsters often spread disease and where diets can be carefully controlled.
Half the children were fed a diet of plain infant formula, the other half the same formula with supplements of bifida and thermophilus. Only 7 percent of the children taking the supplemented formula developed diarrhea, compared with 31 percent of those who did not receive the bacteria.
L Equally important were differences in the spread of disease.
Stool samples showed that only 3 percent of the children on supplements shed rotavirus, the most common viral cause of infant diarrhea. In contrast, 10 percent of the children not on the ,, supplement shed the virus.
The disease is spread not only by children who are visibly ill, but also by youngsters with mild symptoms or none at all.
The study, which appears in tomorrow's British medical journal Lancet, drew on several observations:
Infants who are fed breast milk are less likely to get diarrhea than are bottle-fed babies. One possible reason is that breast milk is a natural source of bifida, a bacterium not found in commercial formula.
It is thought that bifida and other "good bacteria" prevent illness by latching onto the intestinal walls, taking up room that might otherwise be occupied by harmful agents that cause diarrhea.
Increasingly, yogurt makers are voluntarily adding bifida as one of the live cultures that give yogurt its custardy consistency. Under federal law, a product must contain thermophilus and another culture called bulgaricus to be labeled yogurt.
"I'm glad these people at Johns Hopkins did this, because it may focus more attention on the the value of bifida," said Samuel Kaymen, chairman of Stonyfield Farm Yogurt of New Hampshire, one of the first companies to add the bacteria.
He said Japanese food manufacturers have been adding bifida to a variety of foods for about ten years.
"They're using it in miso paste, different sauces and in some of their dairy drinks and soft drinks," he said. "They are so far ahead of us." Miso is a fermented soybean paste that is used as a basic flavoring in Japanese food.