Hello,

After reading Sandra's message asking about an article that had the
following headline and brief note:

Study finds mothers' lifetime lead exposures may put breast-fed newborns at
risk.
Results from a study conducted jointly by Australian and American scientists
indicate that lead which has accumulated in a woman's bones from earlier
exposures can be released during pregnancy and transferred to breast milk
during lactation.

I contacted Monica Campbell at the Environmental Protection Office of
Toronto Public Health.  There have been several extensive community-wide
investigations into lead impacts on health, including mothers and children.
The EPO at Toronto Public Health, in conjunction with South Riverdale
community and the Bathurst-King neighbourhood, (both areas where massive
lead clean-ups took place) have published a number of resources related to
lead levels.  Given their familiarity with the issues, I asked Monica if she
knew of this article or had comments.

In response, she notes:

Sorry, but I don't have a reference for the article that is mentioned in
your e-mail.

I do find the suggestion that lead is transferred in breast milk very
surprising and biologically implausible. Once the article is tracked down,
one would need to "critically appraise" the authors assertions.

What has been demonstrated to date is that women, including pregnant women
but especially women with osteoporsis, do mobilize stored lead from bone
mass and release it into the blood, thereby making it bioavailable to the
fetus because it will pass through the placental tissues virtually
undiminished. Lead has a high affinity for haemoglobin, which is why lead
concentrations are high in red blood cells. However, lead has a low affinity
for fat (i.e. it is not lipid soluble) and therefore occurs in very low
levels in breast milk relative to levels in blood. Some lead lead will reach
the nursing infant via breast milk, however, most studies suggest that the
amount is very small
compared to the direct transfer from the mother in utero via the placenta.
If I had the new study to examine, I would look critically at it to make
sure that lead levels in the neonate were not due to some other external
sources (air, water, dust, soil).

Hope this helps,

Monica Campbell  [[log in to unmask]]
416-395-7685


Other comments??

Alison Stirling
E-mail: [log in to unmask] OR [log in to unmask]