New study findings provide more evidence to dispute the common wisdom that a breast feeding women should have one or two drinks before nursing to optimize the milk supply.

Alcohol does not seem to boost the mother’s production of breastmilk, and actually has a counterproductive effect, the report indicates.

“If a lactating woman is drinking alcohol just because she’s been told to drink (to increase her milk production) there is no scientific evidence that supports this lore,” study author Dr. Julie A. Mennella told AMN Health.

In her study, drinking alcohol before breastfeeding diminished the mother’s production of breastmilk.

Many cultures believe that the quality and quantity of breastmilk can be affected by a mother’s psychological well-being and diet - and that includes the consumption of beer, wine and fermented fruit juices.

Midwives and other healthcare professionals have long touted the benefits of drinking before breastfeeding, believing that it will make infants relax as well as boost the mother’s production of milk.

Previous research has indicated that breastfeeding mothers who consume moderate amounts of alcohol perceive their breasts to be fuller afterwards, but research conducted within the past 10 years suggests that alcohol is not the breastmilk-optimizing substance that many have claimed it to be.

In the current study, Mennella and her colleagues at the Monell Chemical Senses Center in Philadelphia, Pennsylvania, looked at the effect of alcohol drinking on the hormonal response of 17 healthy, nonsmoking women with infants between the ages of 2 and 4 months.

After drinking alcohol-containing orange juice, equivalent to the amount of alcohol in one or two glasses of wine, the women used electric breast pumps to stimulate their production of breast milk. The researchers recorded the amount of time it took for the first droplet of milk to be produced as well as the total amount of milk pumped during a 16-minute period.

Normally, levels of prolactin and oxytocin, hormones crucial to the production and flow of breast milk, rise when babies are at the breast or when breastfeeding moms use breastpumps. When the study participants consumed alcohol, however, their oxytocin levels dropped by 78 percent, levels of prolactin increased more than three-fold, the researchers report in the Journal of Clinical Endocrinology & Metabolism.

These hormones, which usually work in tandem, “go in separate directions” after women have one or two drinks, Mennella said.

The women produced less milk overall, and their breastmilk took longer to flow, the researchers note.

“Yes, mothers will be more relaxed (after drinking), but unbeknownst to them, the hormones that underlie lactation will be disrupted,” Mennella said. Thus, rather than boosting their milk supply, these mothers may “actually produce less milk, (and their) babies drink less milk in the short term,” she added.

The researchers conclude that “the long-term consequences of such disruptions on lactational performance and women’s health, in general, remain unknown.”

By the way, alcohol is not stored in the breasts, so if a mother has a glass of wine, she can safely breastfeed two or three hours later without worrying that her infant will consume alcohol-tainted milk, Mennella noted.

SOURCE: Journal of Clinical Endocrinology & Metabolism, April 2005.