What is A2 protein milk?
What makes A2 protein milk so special?
Once upon a time (thousands of years ago in fact), all cows naturally produced only A2 protein milk1.
Nowadays, A2 protein milk is less common2 and comes from specially selected cows that have a particular genetic history.
Formula milks made with A2 protein milk for babies is a growing trend and is being consumed across the world. But what exactly is ‘A2 protein milk’? And what’s the difference between A2 protein milk and the milk we typically drink?
A moo point...
The credit for A2 protein milk has to go to the cows.
Regular cow's milk contains a mix of two key types of beta-casein protein - A1 and A2 beta-casein. Some cows produce milk that contains one of those, not both. A2 protein milk is made by cows that naturally produce ONLY the A2 beta-casein in their milk.
Making the most of nature
To bring formula milks made with A2 protein milk to your baby, cows that naturally produce only the A2 beta-casein in their milk are specially selected. A2 beta-casein protein was the original beta-casein in cows' milk1.
What is A2 beta-casein protein in milk?
OK, here comes the science…
Cow's milk contains two main types of proteins, known as whey and casein. More specifically (hang in there), beta-casein is one of the major types of casein protein found in cow’s milk.
There are two key types of beta-casein: A1 and A2 beta-casein. A2 protein milk contains only the A2 beta-casein.
Is A2 protein milk good for digestion?
Your baby is growing and developing so fast - blink, and you’ll miss it! One of the things many parents may worry about is their little one's digestion.
Initial studies from adults have shown that A2 protein milk may be easier to digest than regular cow’s milk, which contains both the A1 and A2 beta-casein proteins3,4. This is thought to be because during digestion A2 beta-casein breaks down differently from A1 beta-casein due to a tiny difference in their structure5-8.
What is the difference between A1 and A2 beta-casein protein?
As your baby grows, you’ll watch as they go from the tiny bundle of joy that you first held in your arms, to the happy and healthy little person that you know today. That’s all down to you and your instincts.
If you’re formula or combination feeding, naturally, choosing the type of formula milk they drink is a big deal. So what’s the difference between typical milk containing A1 and A2 beta-casein and A2 protein milk containing only A2 beta-casein? In a nutshell, the difference appears to be all in the digestion.
Did you know?
A1 and A2 beta-casein protein in cow's milk contains a chain of 209 amino acids9!
- Ng-Kwai-Hang KF and Grosclaude F. Genetic polymorphism of milk proteins. In: Fox PF, McSweeney PLH (eds). Advanced Dairy Chemistry: 2002. p. 739-816
- Demirel AF, Cak B. Discussions of effect A1 and A2 milk beta-casein gene on health. APDV. 2018; 3(2):1-6.
- Jianqin S, Leiming X, Lu X, Yelland GW, Ni J, Clarke AJ. Effects of milk containing only A2 beta casein versus milk containing both A1 and A2 beta casein proteins on gastrointestinal physiology, symptoms of discomfort, and cognitive behavior of people with self-reported intolerance to traditional cows’ milk. Nutr J. 2016;15(1):35. doi:10.1186/s12937-016-0147-z
- He M, Sun J, Jiang ZQ, Yang YX. Effects of cow’s milk beta-casein variants on symptoms of milk intolerance in Chinese adults: a multicentre, randomised controlled study. Nutr J. 2017;16(1):72. doi:10.1186/s12937-017-0275-0
- Noni I De. Release of β-casomorphins 5 and 7 during simulated gastro-intestinal digestion of bovine β-casein variants and milk-based infant formulas. Food Chem. 2008;110(4):897-903. doi:10.1016/j.foodchem.2008.02.077
- Ul Haq MR, Kapila R, Kapila S. Release of β-casomorphin-7/5 during simulated gastrointestinal digestion of milk β-casein variants from Indian crossbred cattle (Karan Fries). Food Chem. 2015;168:70-79. doi:10.1016/j.foodchem.2014.07.024
- Asledottir T, Le T, Petrat-Melin B, Devold T, Larsen L, Vegararud G. Identification of Bioactive peptides and quantification of Beta-Casomorphin-7 from Bovine Beta-Casein A1,A2 and I after Ex Vivo Gastrointestinal Digestion. Int Dairy J. 2017;In Press.
- Cieślińska A, Kostyra E, Kostyra H, Oleński K, Fiedorowicz E, Kamiński S. Milk from cows of different β-casein genotypes as a source of β-casomorphin-7. Int J Food Sci Nutr. 2012;63(4):426-430. doi:10.3109/09637486.2011.634785
- Huppertz T et al. Proteins in Food Processing. 2nd ed. Oxford: Woodhead Publishing, 2018.