Hi Ray, 
There are 5 opioid sequences in wheat proteins and 8 opioid sequences in cow
milk. Human milk also contains beta casomorphin 5 and 7.  
I have heard that the opioids from dairy are less potent than those from
wheat, but I'm not sure of that information.
It makes sense to me that the milk of mammals that are subject to predation
would contain opioids...... A very good way of quieting a mildly addicted
infant would be to suckle her/him.

All of these food-borne opioids achieve several things, including
establishing alternate metabolic pathways that would predispose to
addiction. A tendency to overeat and over-indulge in other addictive
substances may, in part at least, be rooted in the opioids found in these
common foods. They may even explain why humans take up eating these
otherwise unnatural foods even though they interfere with absorption of
important dietary minerals and induce allergies, and sometimes, serious
illness. 

Archaeologists have long known that succeeding generations become shorter in
stature and their skeletal remains show reductions in health following
adoption of dietary grains. Whether in Europe or in the Americas, skeletal
remains tell the story of poorer health and smaller size. One example is
from research done on the remains found at or in the Dickenson Mounds, but
there are many such examples.       

Sadly, many of today's bureaucrats and dietitians listen to financial and
political pressures rather than the relevant data. It is impolitic to decry
grains and dairy look at any modern food guide, whether in the USA, Canada,
the UK, etc. They all err on the side of these poor quality foods. 

Best wishes, 
Ron