It's an interesting article but a caveat, which from other posts of yours I tend to expect you'd agree with having a concern on, is that they don't necessarily have evidence.
The Weston A Price people are kind of evidence-phobic, as personal opinion, or at least show no feeling of need for much of it if their theory is satisfying to them without it.
An obvious problem with the theory is that opiates are pretty obviously perceived when at levels sufficient to affect the opiate receptors.
Who is noticing opiate effect from milk?
As it happens considerable work has been done in this area.
From the summary section of the EFSA report on this matter (incidentally, I've been consistently impressed with EFSA's work, which I often consult. They're no industry mouthpiece and frequently impose reductions or bans even on quite conservative measures):
[i]The review covers the following aspects: possible sources of β-casomorphins (BCMs) and
related peptides, polymorphism of β-casein, presence of BCMs and related peptides in food
before digestion, formation of BCM7 and related peptides during human digestion and the
possible molecular interactions of these peptides with the host environment. Furthermore, it
covers the absorption and fate of these peptides, including their possible transfer mechanisms
across the intestinal epithelium, transport in the blood stream and transfer across the bloodbrain
barrier. Finally, possible and suggested organ- and system-specific effects are reviewed,
with specific emphasis on the gastrointestinal, central nervous and cardiovascular systems and
the suggested link with type 1 diabetes mellitus.
This review recognises that proteins, including those present in the diet, are a potential source
of a wide range of biologically active peptides, including some with affinity to opioid
receptors. The latter are also known as opioid peptides.
... Animal data clearly indicate that BCMs, including BCM7, can act as opioid receptor agonists,
probably acting via μ-type opioid receptors. However, in most if not all animal studies to date,
in vivo opioid effects for BCM7 and related milk-derived peptides have only been observed
following intra-peritoneal (i.p.) or intra-cerebro-ventricular (i.c.v.) administration. In
comparison to medicinal and endogenous opioids, bovine BCM7 does not seem to be a very
potent opioid ligand.
... However, the presence of intact β-casomorphin molecules in blood after intake of milk
or casein has not been established in in vivo studies. Opioid peptides, including β-
casomorphin 4, -5 and -7 are highly sensitive to hydrolysis by dipeptidyl peptidase IV thereby
strongly limiting or preventing the transfer of these peptides in an intact form across the
intestinal mucosa and the blood-brain barrier. Available data suggest that in principle,
transport of food-derived peptides and proteins across the human intestinal mucosa is
possible. However, quantitative data on this phenomenon are lacking. In certain cases such as
in neonates and adults with specific diseases, intestinal permeability has been reported to be
significantly increased. In general, the review did not find any quantitative data on the
absorption of intact bioactive peptides for adults, except in the case for di- and tripeptides
with reported antihypertensive properties.
Food-derived peptides, including casomorphins, can have different effects in the intestinal
lumen and the intestinal mucosa, such as regulatory effects on gastro-intestinal motility and
on gastric and pancreatic secretions. Many studies report effects of β-casomorphins on the
central nervous system (CNS) following i.p. or i.c.v. administration in animals. A possible
link between BCM intake and sudden infant death syndrome (SIDS) has been suggested in
some publications. However, no clear evidence for such a relationship was found during the
review. The mechanisms proposed were considered rather speculative and partly
contradictory. Similarly, a link between casein-derived peptides and autism in subjects with
increased intestinal permeability has been suggested. However, recent data do not provide any
support for such a relationship.
It has been suggested that BCM7 might be atherogenic through an oxidative action on LDL.
This mechanism was originally proposed in a single report; however, it has not been
confirmed by later studies. By contrast, numerous in vitro studies indicate that many food
derived peptides/hydrolysates display antioxidant activity. The possibility that BCM7 could
contribute to an increased risk for atherosclerosis has also been suggested from a study in a
rabbit model. This study concluded that β-casein A1 would be atherogenic, in contrast to β-
casein A2 . However, during the review the validity of the experimental model and the
extrapolation to atherosclerosis in humans were not regarded as convincing. Further
speculations for an association between BCM7 intake and cardiovascular disease mortality
have been raised as a result of ecological studies. However, these ecological studies did not
account for several confounding factors. In addition, recent large cohort studies led to
opposite conclusions. Two human intervention studies comparing diets containing β-casein
A1 and A2 did not show a correlation between the estimated β-casein A1 consumption and
development of certain biomarkers for cardiovascular disease (CVD). A limitation of these
studies was the small number of subjects and the short intervention period. Overall, this
review process did not find any strong evidence for a link between the consumption of β-
casein A1 and an increased risk for CVD in humans.
... Moreover, the difference in content of β-casein A1+B in milk produced in countries with high
or low prevalence of IDDM [insulin dependent diabetes mellitus] appears relatively small and does
not explain, from an immunological point of view, the difference in incidence of IDDM across countries.
Based on the present review of available scientific literature, a cause-effect relationship
between the oral intake of BCM7 or related peptides and aetiology or course of any suggested
non-communicable diseases cannot be established.[/i]
The report itself has another 102 pages or so, which I haven't read yet, will post back when I have.
I would have suspicion that these "biodynamic farming" folk may be grabbing stuff which doesn't prove anything, except when wishing it to "prove" something. I'm not saying they must be wrong, it's just that it would hardly surprise me and it would hardly be the first time.