I agree, it's really hard to find consistent information out there about how much alcohol is "safe" while breastfeeding. Some of the things I've read say that if your body has metabolized it, then it is generally assumed that it won't reach your milk. I also agree that most Americans (and American organizations) take a pretty conservative view towards alcohol consumption while pregnant and breastfeeding. It's a pretty personal choice. For me, if I plan to drink, I tend to do so right after I've fed my daughter and I make sure I've stopped at least an hour before her next feeding. The only time I refrained from having an occasional glass of wine or beer was when she was first born.
However, I did find this article:
http://pediatrics.aappublications.org/cgi/content/full/10...
It's rather long, but interesting. I skimmed it, but did see this (the numbers in the text are footnotes):
"Because alcohol is excreted to a limited extent in breast milk,5,8,9 occasional exposure often is considered insignificant,8,10 except in such rare cases of intoxication when the mothers of breastfeeding infants drank quite heavily11,12 or when infants were inadvertently fed large amounts of alcohol in a bottle.13 Moreover, an epidemiologic study14 found no significant difference in the motor and mental development of 1-year-old breastfed infants whose mothers drank less than one drink per day, compared with either breastfed infants whose mothers did not drink at all or those who were formula-fed. Only those infants who were exposed regularly (at least daily) to alcohol in their mothers' breast milk, showed a slight, but significant deficit in gross motor, but not mental, development. Perhaps the developing brain is extremely sensitive to alcohol or the small amounts ingested in breast milk accumulated in the infant because it is metabolized or excreted more slowly than in children and adults.14"