Todd Moody wrote:
>
> Is there a scientific basis for the claim that the casein of each
> species is molecularly different?
>
Yes, it looks as though there are several different caseins in the milk
of any given species, such as alpha, beta, and kappa. Not only that, but
the beta-casein in cow milk is different from the beta-casein in human
milk. I've included some snippets from web searches that you might find
interesting. The first two are from siobhan's milk citations. Number
five is particularly interesting. They want to grow human milk in potato
plants! That might be great for women who can't breastfeed. The problem
as I see it, is that probably 99 percent of women CAN breastfeed, except
they get sabotaged by hospitals, doctors, corporate greed, and twisted
cultural pressures, and the availability of GM human milk will give them
more reasons not to do the natural thing. But I digress. Stacie said:
"It's not so much that "casein" is a problem for people, but *foreign*
milk proteins". That seems to be true, but just to clarify, bovine
beta-casein IS a foreign protein, being slightly different from the
human version, and it is a major allergen for babies. See note #5 below,
and #2.
cheers,
Hilary McClure
Danville, VT
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1.
"Cow's milk is one of the most frequent food allergens. Whole casein
appears to be highly allergenic...85% of the patients presented a
response to each of the four caseins. "
Int Arch Allergy Immunol, 1998 Mar, 115:3
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2.
"Antibodies to bovine beta-casein are present in over a third of IDDM
patients and relatively non-existent in healthy individuals."
LANCET, October, 1996, 348
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3.
from <http://nrg.ncl.ac.uk/research/resareas/residue/residue2.html>:
what can proteins tell us about ancient ceramics?
Proteins are found in almost all biological tissues. They show immense
variation in structure due to changes in their primary amino acid
composition and hence have a huge range of biological functions.
Proteins with the same function may also show small variation between
species due to differences in the DNA sequence which codes for them.
The variation between proteins with different function and from
different species makes proteins ideal biomarkers for different
foodstuffs. For example, it is possible to distinguish bovine albumin
(blood protein) from bovine casein (milk protein) and bovine casein
from human casein, by using antibodies which recognise small
differences in protein structure. The detection of different proteins
associated with archaeological ceramics could therefore aid
interpretation of ceramic artefact use. Recently, we have demonstrated
this by distinguishing bovine blood and bovine milk in Bronze Age and
Iron Age assemblages.
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4.
from<http://iubio.bio.indiana.edu/R25355-28634-/news/bionet/molbio/gdb/9512.newsm>
Which species are you interested in? I can give you some information
about
human casein genes from GDB and OMIM.
According to OMIM (http://www3.ncbi.nlm.nih.gov/Omim/) there are three
caseins in bovine milk, alpha, beta and kappa. However, humans have only
two of these proteins - either alpha and beta (according to the alpha
casein entry - MIM number 115450) or beta and kappa (according to the
beta
casein entry - MIM number 115460). I suspect that alpha and beta is
correct for humans.
GDB (http://gdbwww.gdb.org/) has entries for human alpha and beta casein
genes. Alpha casein has the symbol CSN1, beta has the symbol CSN2. It
appears that the alpha gene has not yet been mapped or cloned; however,
the beta gene has been cloned and mapped to 4p16.3-q21 in humans.
To find probes for human beta casein, point your web browser at the GDB
home page at:
http://gdbwww.gdb.org/
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5.
from<http://www.plant.uoguelph.ca/riskcomm/archives/agnet/1998/7-1998/ag-7-20-98-2.txt>:
HUMAN MILK CASEIN PRODUCED IN TRANSGENIC POTATOES
July 1998
CAB International
http://agbio.cabweb.org/
The human milk protein b -casein is now being grown in transgenic potato
plants by a research team from the Center for Molecular Biology and Gene
Therapy (Loma Linda, California, USA). Human b -casein mRNA was
identified
in leaf and tuber tissues of transformed potato plants. The aim is to
reconstitute human milk in edible plants and use this to replace bovine
milk in baby foods. This will improve infant nutrition, and prevent
gastric and intestinal diseases in children.
Human casein consists mainly of b - and k -caseins. The b -casein is the
most abundant (70%), while the k -casein accounts for only 27% of total
casein content. Like other milk proteins, lactoferrin, IgA and lysozyme,
b
-casein and b -casein fragments have several beneficial effects. These
include enhancement of calcium absorption, immunostimulating and
modulating effects, and antibacterial functions.
Mother's milk is recommended by the nutritional and paediatric
communities
as the best food for suckling infants. For non breast-fed infants,
bovine
milk-based formulas have been regarded as a suitable substitute.
However,
human milk is markedly different from bovine milk. The amino acid
composition of the caseins differ substantially and a -casein
predominates
in bovine milk, but is almost absent from human milk.
Cow's milk can be responsible for gastrointestinal disease and even
digestive collapse of newborn infants fed a cow milk-based diet. The
main
cause of this allergenicity of cow's milk appears to be the b -casein.
Despite immunological problems with cow's milk and cow's milk-based
formulae, these have become the primary source of infant nutrition in
the
Western world due to their availability and convenience. The
plant-produced b -casein is identical in amino acid sequence to the
human
b -casein and can be used in infant formulae. In the future, other human
milk proteins, such as lactoferrin and lysozyme, will be added to the
casein-producing potatoes.
This will provide a more complete human milk formula for improving
infant
growth and providing greater protection against infant diseases.
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