By Matt Leingang
Enquirer staff writer

Researchers at Cincinnati Children's Hospital Medical Center have identified the ingredient in human breast milk that provides powerful protection against severe diarrhea in infants.

The discovery, reported in this week's Journal of Pediatrics, could lead to new medications in the fight against infectious diarrhea in children and adults, preventing millions of deaths worldwide.

Physicians have long known about the antibodies in human breast milk that give babies a kind of natural immunity against ear infections, bacterial meningitis and certain kinds of disease, including infectious diarrhea.

But a previously unknown mechanism, responsible for most of this immunity, also seemed to be at work.

Researchers now say complex sugar molecules - called oligosaccharides - act as a decoy, causing diarrhea-inducing viruses to attach to them instead of a baby's gastrointestinal tract.

"This gives us another reason to emphasize the importance of breastfeeding," said Ardythe Morrow, a researcher at Children's Hospital and the study's lead author. "These sugars are not found in baby formula or in cow's milk off the shelf."

Although it could be at least five years before scientists are able to duplicate the sugars and produce new drugs, Morrow called the discovery an important first step.

Children's Hospital, along with two partners in the study - the University of Massachusetts and the National Institute of Medical Science and Nutrition in Mexico City - have formed a company to develop and test such drugs.

Serious, acute diarrhea - severe enough to require a doctor visit or hospitalization - can be caused by a variety of viruses and bacteria spread by person-to-person contact.

And it can be deadly, particularly in children. Infectious diarrhea kills 2.5 million children under the age of 5 each year, mostly in developing countries, Morrow said.

In the United States, children in day care typically suffer two to three bouts of acute diarrhea a year, Morrow said.

Data for the breast-milk study was provided by 93 breastfeeding mother-infant pairs in Mexico City, where the U.S. National Institute of Child Health and Human Development, which funded the study, has a lab.

The amount of oligosaccharides in breast milk varied, largely because of genetics. But the study showed that the 77 infants who received milk with high amounts of the molecules had fewer incidents of moderate to severe diarrhea.

The study is welcome news for La Leche League of Cincinnati, which provides support and encouragement for women who wish to breastfeed.

"Mothers always ask us about the health benefits, and this is one more thing we can point to," said La Leche member Angie Theil, Loveland, mother of two girls.

Breastfeeding

Intestinal infections are rare in exclusively breastfed babies, studies show.

In 2001, a majority of women in the United States tried to breastfeed their infants:

• 70 percent of women were breastfeeding when they left the hospital

• 33 percent were still breastfeeding their babies at 6 months of age.

Source: March of Dimes

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E-mail mleingang@enquirer.com