Isoflavones:

There are several articles in a recent Clinical Chemistry journal that I found
very interesting concerning the presence of two unique chemicals in breast milk
following a soy meal.

Joanne Slavin. Clin Chem 42(6):841-2, 1996.
A.A. Franke and LJ Custer. Clin Chem 42(6): 955-964, 1996.

Apparently, daidzein and genistein which are isoflavones are secreted into
human milk following a soy bean meal.  This is very interesting because these
compounds have been found to be potent anticancer agents, and the authors
surmise that these agents could account for some of the anticancer properties
of human milk.  It is somewhat difficult reading (at least for me),  but it
should peak your interest.

More importantly, however, is the leading article in this journal(Slavin) which
is titled "Phytoestrogens in Breast Milk - Another Advantage of Breast-feeding
?

This brief review explains the intense interest in soy phytoestrogens and some
of their anticancer properties.  Interestingly,  soy based infant formula has
NONE of these good isoflavones.

So if you are interested in this subject, check this journal out.

Tom Hale