The casein portion of all species' milk includes several kinds of caseins,
and most species milk has some beta-casomorphins which are natural opiates.
Since human milk has a low casein-to-whey ratio (starting at 10:90 then
changing gradually to 40:60 by about 6 months, the breastfed newborn doesn't
get much of this substance.

Before anyone panics, take a look at the biggest competitor to human milk:
the dairy cow, whose milk is 82% casein, and with beta-casomorphins that are
10-30 times more potent than those in human milk. (Peter Hartmann, 1990 and
elsewhere). Processing may reduce the casein-to-whey ratio, but not the
potency of the naturally-occurring opiates.

Linda J. Smith, BSE, FACCE, IBCLC
Bright Future Lactation Resource Centre www.bflrc.com
6540 Cedarview Ct., Dayton, OH 45459-1214 USA
(937) 438-9458 email [log in to unmask]

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