(04-06-2013, 10:11 AM)Tropico Ha scritto: "Per favore registrati qui per vedere il link :-) "Dovremmo cercare anche che tipo di caseine ha il latte di capra, come per le mucche A1 vs A2.
La storia della variante A1 o A2 non e’ancora stata provata. E’una bella, intelligente ed elegante teoria che bisogna dimostrare. Da quel che ho potuto trovare sui miei vecchi libri e da internet, la β-casina delle capre contiene tutte e due le varianti...ma con propozioni diverse a seconda delle razze. La proporzione dei due allelei A1/A2 varia molto tra le razze. Le razze autoctone e piu antiche hanno addirittura una altra variante della β-casina la D.
Beta-casein is a class of cow's milk protein that may provide effects beyond nutrition, due to the release of biologically active peptides on digestion (1). Beta-casein may be present as one of two major genetic variants: A1 and A2 (2). A2 beta-casein is recognised as the original beta-casein protein because it existed before a mutation caused the appearance of A1 beta-casein in European herds a few thousand years ago (3, 4).
The major difference between the A1 and A2 beta-casein proteins is a single amino acid at position 67 in a strand of 209 amino acids. A1 beta-casein has the amino acid histidine at position 67, while A2 beta-casein has a proline amino acid in the same position (Figure: 1). A1 beta-casein in cow's milk is different to other mammalian beta-caseins, because of its histidine at position 67. Human milk, goat milk, sheep milk and other species’ milk contain beta-casein which is ‘A2 like’, because they have a proline at the equivalent position in their beta-casein chains (5-7). The A1 beta-casein protein has been implicated as a potential etiological factor in type 1 diabetes mellitus, ischaemic heart disease and also as a modifier of behavioural symptoms associated with some neurological conditions such as autism. A2 beta-casein has not been implicated in these conditions (see the Science Overview page for details).
Figure 1: A1 and A2 beta-casein proteins showing the amino acid difference at position 67. This difference can be detected easily by a non-invasive DNA test which indicates accurately which beta-casein genes a cow carries.
A1 and A2 Beta-casein Genes
The bovine beta-casein gene is part of a cluster of 4 casein genes (alpha-S1-casein, alpha-S2-casein, beta-casein and kappa-casein) located on chromosome six (8). A1 and A2 are the most common beta-casein alleles (genetic variants) in dairy cattle, although other minor alleles exist (Figure: 2) (2, 4, 9). The A2 beta-casein gene is recognised as the progenitor of the beta-casein gene in the genus Bos, the genus of bovine animals to which cattle belong. As one gene is inherited from each parent, each cow can only carry two copies of the beta-casein gene but cows can, of course be homozygous or heterozygous for the A1 and/or A2 beta-casein allele. This, together with co-dominance, whereby one allele does not over-ride the other, means that a cow can only produce at most two types of beta-casein in its milk, and if she does carry two different alleles then the two forms will be produced in a 1:1 ratio.
Figure 2: Evolution of beta-caseins in cow’s milk from the original A2 type beta-casein. The same amino acid difference at position 67 occurs between the minor variants, so these sub-variants may be classified as 'A1 like' or 'A2 like'. 'A2 like' sub-variants include A3, D, E and possibly H and have a proline at position 67. 'A1 like' sub-variants include B, C, F, G and possibly H and have a histidine and share the capacity to produce BCM-7 with A1 beta-casein. [adapted from Formaggioni et al., 1999 (2)].
A2 beta-casein is found in all types of bovine animals, including all Western, African and Indian cattle and water buffalo. A1 beta-casein is carried by some cows of European breeds, all of which belong to the subspecies Bos taurus (10). However, the prevalence of the A2 and A1 beta-casein allele varies between cow herds and also between countries. For instance, a recent study on the beta-casein allele frequency in indigenous Indian cattle (Bos indicus) and river buffalo breeds (618 animals of 15 zebu cattle breeds and 231 buffaloes of 8 river buffalo breeds) reported 99 to 100% presence of the A2/A2 genotype in its indigenous cow (0.987) and buffalo (1.00) breeds (11). The same study also reported an absence of the A1/A1 genotype, thus in Indigenous Indian cow and buffalo breeds, nearly all animals are homozygous for the A2 beta-casein allele. Turning to European breeds, the Holstein, which is the most common dairy cow breed in Australia, Northern Europe and the US, carries the A1 and A2 beta-casein alleles in approximately equal distribution. Jersey herds typically have an A2 allele frequency somewhat higher than this, but with considerable between-herd variation. Also, some Jersey cows carry the “B” beta-casein allele which has been shown to give an even higher release of BCM7 (12). The Guernsey breed has an A2 beta-casein allele frequency of more than 90% (13).
1. Phelan M, Aherne A, FitzGerald R.J, O’Brien N.M, (2009). Casein-derived bioactive peptides: Biological effects, industrial uses, safety aspects and regulatory status. International Dairy Journal. 19(11), 643–54. External link
2. Formaggioni P, Summer A, Malacarne M, Mariani P, (1999). Milk protein polymorphism : Detection and diffusion of the genetic variants in Bos genus Parma: Universiti degli Studi de Parma, Annalli della Facolta di Medicina Veterinaria. External link.
3. Ng-Kwai-Hang K,F. Grosclaude F, (2002). Genetic polymorphism of milk proteins. In: Fox PFaM, P.L.H editor. Advanced Dairy Chemistry: Volume 1: Proteins, Parts A&B. New York: Kluwer Academic/Plenum Publishers. p. 739-816. External link.
4. Kaminski S, Cieslinska A, Kostyra E, (2007). Polymorphism of bovine beta-casein and its potential effect on human health. J Appl Genet. 48(3), 189-98. External link.
5. Lonnerdal B, Bergstrom S, Andersson Y, Hjalmarsson K, Sundqvist A,K. Hernell O, (1990). Cloning and sequencing of a cDNA encoding human milk beta-casein. FEBS Lett. 269(1), 153-6. External link.
6. Provot C, Persuy M.A, Mercier J.C, (1989). Complete nucleotide sequence of ovine beta-casein cDNA: inter-species comparison. Biochimie. 71(7), 827-32. External link.
7. accession e. Goat beta-casein [cited 2011 3 October]. External link.
8. Rijnkels M, (2002). Multispecies comparison of the casein gene loci and evolution of casein gene family. J Mammary Gland Biol Neoplasia. 7(3), 327-45. External link.
9. Farrell H.M Jr., Jimenez-Flores R, Bleck G.T, Brown E.M, Butler J.E, Creamer L.K, et al. (2004). Nomenclature of the proteins of cows' milk--sixth revision. J Dairy Sci. 87(6), 1641-74. External link.
10. Woodford K, (2007). Devil in the Milk: Illness, Health and Politics: A1 and A2 Milk. Wellington New Zealand: Craig Potton Publishing. External link.
11. Mishra B.P, Mukesh M, Prakash B, Sodhi M, Kapila R, Kishore A, et al. (2009). Status of milk protein, ß-casein variants among Indian milch animals. Indian Journal of Animal Sciences.79(7), 722-5. External link.
12. De Noni I, (2008). Release of b-casomorphins 5 and 7 during simulated gastro-intestinal digestion of bovine b-casein variants and milk-based infant formulas. Food Chemistry. 110(4), 897-903. External link.
13. Scientific Report of EFSA prepared by a DATEX Working Group on the potential health impact of beta-casomorphins and related peptides. EFSA Scientific Report (2009) 231, 1-107 [cited 3 October 2011]. External link.
Breaking the vicious Cycle
: Casein Sensitivity
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Casein is only an issue if someone is *sensitive* to it. I use the word sensitive, because very few people are truly allergic to it (If you've been properly allergy tested and have tested positive for casein allergy,
then you should not use milk and should carry an Epipen with you as well as wearing a Medicalert bracelet.) If someone has leaky gut, and improperly digested casein is getting into their system, then they are
going to react because inappropriate proteins are what the immune system is designed to attack. The other problem is that the peptides that result from incompletely broken down casein behave like opioids and they will have a similar CNS effects.. hence, brain fog, lethargy, etc.
BUT... there are lots of different kinds of casein, and the casein that's found in cow milk is the one that people generally react to. This is REALLY IMPORTANT to remember, since dairy can be in important
source of calories and there's no point removing something from your diet that you don't have to... so, I'm going to say it again.... there are lots of different kinds of casein, and the casein that's found in cow milk is the one that people generally react to. So... I did a very simple Google search using the words, "casein cow vs. goat milk" and here's what I got....
From: "Per favore registrati qui per vedere il link :-) "
"There is only an 85% overlap in milk protein makeup across different species so people who have an unusual milk allergy, or who are merely lactose intolerant, may find that a milk other than cow's milk is
digestable. Also, remember that since each mammal has protein and sugar variants in their milk, it's possible to be allergic to the milk of only one, or one set of, mammals."
From: "Per favore registrati qui per vedere il link :-) "
"Apha-s1 is the major casein protein present in cow milk and has been identified as one of the major cow milk allergens. By contrast the major casein in goat milk is ß-casein, and alpha-s2 casein is the main alpha
From: "Per favore registrati qui per vedere il link :-) "
"Unlike cow's milk, goat's milk does not contain agglutinin. As a result, the fat globules in goat's milk do not cluster together, making them easier to digest. Like cow's milk, goat's milk is low in essential fatty
acids, because goats also have EFA-destroying bacteria in their ruminant stomachs. Yet, goat milk is reported to contain more of the essential fatty acids linoleic and arachnodonic acids, in addition to a higher
proportion of short-chain and medium-chain fatty acids. These are easier for intestinal enzymes to digest. Different protein. Goat milk protein forms a softer curd (the term given to the protein clumps that are formed
by the action of your stomach acid on the protein), which makes the protein more easily and rapidly digestible. Theoretically, this more rapid transit through the stomach could be an advantage to infants and children
who regurgitate cow's milk easily. Goat's milk may also have advantages when it comes to allergies. Goat's milk contains only trace amounts of an allergenic casein protein, alpha-S1, found in cow's milk. Goat's milk
casein is more similar to human milk, yet cow's milk and goat's milk contain similar levels of the other allergenic protein, beta lactoglobulin. Scientific studies have not found a decreased incidence of allergy with goat's milk, but here is another situation where mothers' observations and scientific studies are at odds with one another. Some mothers are certain that their child tolerates goat's milk better than cow's milk, and mothers are more sensitive to children's reactions than scientific studies. Less lactose. Goat's milk contains slightly lower levels of lactose (4.1 percent versus 4.7 percent in cow's milk), which may be a small advantage in lactose-intolerant persons. Different minerals. Although the mineral content of goat's milk and cow's milk is generally similar, goat's milk contains 13 percent more calcium, 25 percent more vitamin B-6, 47 percent more vitamin A, 134 percent more potassium, and three times more niacin. It is also four times higher in copper. Goat's milk also contains 27 percent more of the antioxidant selenium than cow's milk. Cow's milk contains five times as much vitamin B-12 as goat's milk and ten times as much folic acid (12 mcg. in cow's milk versus 1 mcg. for goat's milk per eight ounces with an RDA of 75-100 mcg. for children). The fact that goat's milk contains less than ten percent of the amount of folic acid contained in cow's milk means that it must be fortified with folic acid in order to be adequate as a formula or milk substitute for infants and toddlers, and popular brands of goat's milk may advertise "fortified with folic acid" on the carton."
Also lots of info at: "Per favore registrati qui per vedere il link :-) "
So.. the upshot is, all milk has lots of casein in it.. otherwise it wouldn't BE milk... but there are different types of casein and for someone who has a casein sensitivity, goat milk may provide an alternative to which they don't react.
If you have a true casein allergy, then no milk will work for you.. but remember, true allergies to casein are pretty rare, and allergy tests may be inaccurate and all the more so for someone with IBD. If you've had an
anaphylactic reaction to milk in the past, then you should never eat any dairy, ever.. but if you just feel a wonky when you have dairy, you may just have a sensitivity and as you heal, that sensitivity may go away.
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