I dug out my husband's NEJM of Nov 19, 1998 (Vol 339, #21) and checked the
letter re smoking and breastfeeding.  It was kind of odd because it didn't
seem to be in response to a former article.  Maybe they just wanted to get
printed in the NEJM without having to submit their study?
I'm not sure if it's kosher to reprint the entire letter here.  The first
paragraph states: "Children whose mothers smoke have an increased risk of
smoking during adolescence.  One mechanism underlying the relation may involve
early learning of flavors, since a variety of flavored substances that are
transmitted from the mother's diet to her breast milk can be detected by the
nursling.  In view of the vast array of inherent and added flavors found in
cigarettes, we tested whether the odor and, consequently, the flavor of human
milk is altered by smoking."
They took FIVE smokers and had them refrain from smoking for 12 hrs, then
express 15 ml of milk.  They then put on a disposable lab coat and gloves,
entered an environmental chamber and smoked one or two cigarettes in a 20
minute period.  She then took off the coat and gloves, washed her hands and
left the chamber.  She provided additional 15 ml samples at 30 minutes, and
1,2,3, and 4 hours after smoking.
A "sensory panel" of seven adults then evaluated the odor of the milk.  All
possible pairs from each woman were presented twice, one sample at a time in
random order, to each panelist in a "blinded fashion".  Nicotine content was
also analyzed by gas chromatography.
I will quote the final paragraph: "The results were unambiguous.  The
panelists were more likely to identify samples collected from the women 30
minutes to 1 hour after smoking as smelling 'stronger' or 'more like
cigarettes' than the other samples (P<0.001).  These data clearly confirm
previous reports that breast milk can be a source of exposure to nicotine and
demonstrate that changes in the odor of milk parallel the changing
concentrations of nicotine.  These findings raise the possibility that in
addition to the effects of nicotine on the developing brain, early experiences
with the flavor of tobacco in breast milk (and perhaps even in amniotic fluid)
influence the likelihood that exposed children will find these flavors
appealing later in life.  We do not suggest that lactating women who smoke
occasionally should stop nursing.  However, the knowledge that the milk of
others who smoke smells and may taste like cigarettes provides additional
reason to avoid smoking."  The letter is by Julie A. Mennella, PhD and Gary K.
Beauchamp, PhD at the Monell Chemical Senses Center, Philadelphia PA
19104-3308.
Obviously these people are interested in sensory experiences.  I would imagine
that teenagers are much more affected by growing up in a household where they
can see adults smoking and have access to purloined cigarettes, rather than
the "remembered" taste of nicotine in the breast milk.
Cynthia D. Payne
LLL of Berkshire County Massachusetts