Babies Nurse Less When Mothers Drink : Health: Research challenges traditional advice that women who are nervous about breast-feeding consume a little alcohol to relax.

Just one alcoholic drink before breast-feeding appears to alter the taste of breast milk and perhaps for that reason reduces the amount an infant consumes, according to a new study that challenges the traditional advice that anxious, nursing mothers have a drink to relax.

The study, published today in the New England Journal of Medicine, found that babies whose mothers had had the equivalent of one beer consumed 23% less milk than usual and that the milk smelled--and therefore probably tasted--distinctly different.

“In the narrowest sense, their findings imply that physicians should be circumspect in recommending that mothers who have difficulty with breast-feeding consume small quantities of alcohol,” Dr. Janine Jason, a pediatric immunologist, wrote in an editorial.

The study’s authors, however, emphasized that they were neither advising against breast-feeding nor necessarily ruling out an occasional drink. Experts said a healthy baby who consumes less milk at one feeding would probably compensate in later ones.

“We’re certainly not suggesting that there is a danger to breast-feeding,” said Gary K. Beauchamp of the Monell Chemical Senses Center in Philadelphia. “What we think is that mother’s milk is a rich source of information about her diet.”

Beauchamp and a colleague, Julie A. Mennella, studied 12 lactating mothers and their infants. Immediately before breast-feeding, the researchers gave them either orange juice or orange juice mixed with the amount of alcohol normally found in a can of beer.

After each feeding, the researchers weighed the babies to measure their intake. They also had samples of the women’s breast milk sniffed by a panel of 17 adults who had been screened for “normal olfactory thresholds” for alcohol.

“Because odor is a primary component of flavor, it can confidently be predicted that if the odor of milk changes, its flavor changes also,” wrote the researchers, whose center is the world’s only scientific organization devoted exclusively to exploring taste and smell.

The researchers found that the infants exposed to alcohol consumed 23% less than they did otherwise and that the milk containing alcohol smelled strikingly different, with changes in the intensity of the odor paralleling concentrations of alcohol.

The amount of alcohol ingested by an infant through breast milk is a minute fraction of the mother’s intake, the researchers said.

The group speculated that the drop in the babies’ consumption could be attributed either to the changed flavor of the milk or to the alcohol’s effect on the babies, or to a decrease in milk production.

Jason, however, cautioned women and doctors against overreacting to the findings.

On the one hand, she said, there is no evidence that an occasional drink by the mother will harm a baby. But on the other hand, she said, any time a breast-feeding woman takes a medication or any other potentially dangerous substance, she should discuss it with her doctor.

“If a mother has a glass of wine for dinner on a Saturday night and the baby doesn’t consume as much in the next feeding, a normal, healthy baby will make up for that a few feedings after that,” Jason said.