A1 Beta Casein Protein Intolerance vs
Lactose Intolerance


Dairy foods including milk, cheese and yoghurt provide essential calcium and protein and is recommended to be included as part of a healthy diet. However for a growing number of people, consuming dairy foods can cause many symptoms ranging from skin conditions such as eczema, to gastrointestinal symptoms of diarrhoea or constipation. Symptoms are associated with either an allergy to the dairy protein involving the immune system, or an intolerance to the dairy protein or the dairy sugar known as lactose.

Lactose is present in all mammalian milk including human milk.  The lactose molecule is a disaccharide represented as 2 sugars bound together by 1 bond – the sugars are glucose & galactose. The Lactose molecule is the same (uniform) across all mammals however the amount present varies between 2-9%.  Human milk lactose levels are approx. 7%[1], while milk (bovine or cows) is between 4-5%[2].  Infant formula based on cow’s milk has adjusted levels of lactose to be aligned with levels in human milk.

68% of the world’s population identify themselves as intolerant to dairy[3] and most people believe their intolerance is due to lactose. But what if that’s not the case?

True lactose intolerance, where the body is unable to digest the dairy sugar, is less common than is widely perceived, and is only one potential cause of cows’ milk intolerance. There is increasing scientific evidence that the A1 beta-casein protein found in standard dairy milks may be associated with cows’ milk intolerance.

In humans, digestion of the A1 beta-casein protein found in regular dairy products produces a peptide (smaller protein) known as beta-casomorphin-7 (BCM-7). BCM-7 activates opioid receptors throughout the gastrointestinal tract and body which can mimic the symptoms of lactose intolerance in sensitive systems. In dairy products that only contain the A2 beta- casein protein, BCM-7 is not produced and therefore can be gentler on the gut.

Human research involving a double-blind, randomized cross-over study showed that participants consuming A1 beta-casein type cows’ milk experienced statistically significantly looser stools compared with those receiving A2 beta-casein milk. Additionally, a statistically significant positive association between abdominal pain and stool consistency was observed when participants consumed the A1 but not the A2 diet[4]

Those babies, children or adults  diagnosed by a health care professional with a cow’s milk protein allergy,  need to avoid all cow’s milk proteins including A1 and A2. A health care professional such as Paediatrician, GP or specialized Dietitian can help determine whether symptoms are associated with an allergy or intolerance. There are a small number of babies that are lactose intolerant and are unable to breast feed.  They must have their own specialised formula.  Equally there are those that are allergic to cow’s milk all together and must avoid all dairy products.

For the vast majority of babies, they are able to breast feed and digest the lactose.  It is when they transfer to regular cow’s milk after breastfeeding that they experience intolerance symptoms, for example bloating and constipation. It is at this point that they attribute these symptoms to a component found in cow’s milk (which could be various components in the milk including Lactose).   The key thing to remember is that the lactose molecule is exactly the same in human milk and cow’s milk.  Perhaps there are other factors contributing to symptoms including ethnicity, a drop in lactase production or the status of the gut[5]; however it could equally be attributed to the presence of the A1 beta casein protein, which is absent in human milk.

Milk and dairy intolerance is a complex problem of importance both to public health and individual health. It is clear that lactose malabsorption (and consequent symptoms) is one element of the syndrome, but it is also evident that there are other factors that play an important role. The potential role of A1 beta-casein is arguably the prime candidate requiring closer scrutiny if understanding is to be advanced[4].

[1] Jenness R. The composition of human milk. Semin Perinatol. 1979 Jul;3(3):225-39. PMID: 392766

[2] Steve Hertzler, Dennis A. Savaiano, Abby Dilk, Karry A. Jackson, Sinead N. Bhriain, Fabrizis L. Suarez, Chapter 40 – Nutrient Considerations in Lactose Intolerance, Editor(s): Ann M. Coulston, Carol J. Boushey, Mario G. Ferruzzi, Linda M. Delahanty, Nutrition in the Prevention and Treatment of Disease (Fourth Edition), Academic Press, 2017, Pages 875-892, ISBN 9780128029282, Adv. Nutr. 2017 Sep; 8(5): 739–748.

[3] Storhaug CL, Fosse SK, Fadnes LT. Country, regional, and global estimates for lactose malabsorption in adults: a systematic review and meta-analysis. The Lancet. Gastroenterology & Hepatology. 2017;2(10):738–746.

[4] Milk Intolerance, Beta-Casein and Lactose.  Sebely Pal, Keith Woodford, Sonja Kukuljan, Suleen Ho.  Nutrients. 2015 Sep; 7(9): 7285–7297

[5] Lactose Intolerance. Mayo Clinic

Special Thanks to Dietitian Kate DiPrima for her contributions to this article.

A cup of cow’s milk provides around 8g of protein and contains 9 of the essential amino acids (or the basic building blocks for protein formation) required by humans.

There are two main categories of milk proteins – casein and whey.  They differ both in their chemical composition and their physical appearance.  In cow’s milk approximately 80% of milk protein is casein and the remaining 20% is whey, whereas human milk is 40% casein and 60% whey.

The casein family of protein consists of several types of caseins including alpha-s1, alpha-s2 and beta casein. Each has its own amino acid composition, genetic variations, and functional properties [1].  The whey protein (also referred to as the serum protein) consists of approximately 50% ß-lactoglobulin, 20% α-lactalbumin, blood serum albumin, immunoglobulins, lactoferrin, transferrin, and many minor proteins and enzymes.  It is the beta casein protein component in cow’s milk that has attracted the attention of the science world with much research undertaken into the effect that digestion of the protein has on the human gut. Beta casein makes up about 30% of the total protein contained in cow’s milk and may be present as either the A1 or A2 major genetic type [2].

Most dairy milk produced commercially in Australia and internationally contains a mixture of A1 and A2 beta casein proteins however there are companies such as Beta A2 Australia which produce milk products that contain only the A2 beta casein.

Digestion of the A1 or A2 beta casein chains into smaller peptides and amino acids is where the major difference between the two proteins lies. During digestion of the A1 beta casein, a peptide known as Beta Casomorphin-7 (BCM-7) is produced[2]; this appears to be absent during digestion of the A2 beta casein protein. It’s the opioid like affect that this peptide has on the human gut that is driving health care professionals to investigate the difference in tolerance between different milks.

There are many scientific studies and research assessing the presence of the BCM peptide and subsequent gastrointestinal effects reported in some people. Some of the reported effects include delayed transit time through the bowel, affecting stool consistency [3], inflammation, and digestive discomfort including bloating, abdominal pain and flatulence [2]. Other symptoms reported in a recent study were those usually associated with lactose intolerance including increased gastrointestinal inflammation and worsening of post dairy digestive discomfort [4].

Consuming standard cow’s milk with a combination of A1 and A2 beta casein proteins will not necessarily affect everyone, however those presenting with unresolved gastrointestinal distress such as bloating, flatulence and poor emptying of the bowels may benefit from trialing a milk that is free of the A1 protein.

It’s important to remember, the benefits of A2 only protein milk are not just for those with gastrointestinal symptoms, it may simply ease the intestinal load and therefore equally benefit even those with healthy digestive systems.

Beta A2 Australia is a privately owned and operated Australian company based in Victoria. They produce a premium nutrition range ‘Farmers Beta A2’, based on home grown Australian A2 protein milk, that is naturally free of A1 beta casein.

What’s an easy way to describe the difference between regular milk and A2 milk?

Most people know that Whey Protein is an extract from milk, another type of naturally occurring protein in milk is Casein Protein.  There are a number of types of Casein Protein, two of which are A1 & A2 Beta Casein Protein.

Most cow’s milk contains both A1 & A2 Beta Casein Protein.  Farmers Beta A2 use milk from cows which naturally produce milk that does not contain the A1 Beta Casein Protein.   Hence the name A2 protein milk.

How do you remove the A1 protein from the milk? 

There is no need to remove A1 Beta Casein Protein.  The milk we use naturally does not have the A1 beta casein.

Just like humans have different blood types based on their genetics, cows can naturally product milk containing either A1 & A2 milk, OR A2 ONLY milk, it’s just a matter of genetics. 

Farmers may have a full A2 ONLY producing herd, or they may segregate the milk from the A2 ONLY cows that are naturally in their herds.

How are the cows selected?

The selection of cows is based on genetic testing. 

We test our milk for the absence of A1 protein once it is received.

Does A2 protein milk taste different?

A2 protein milk does not taste different.  It is delicious natural dairy milk.

[1] http://www.milkfacts.info/Milk%20Composition/Protein.htm

[2] Systematic Review of the Gastrointestinal Effects of A1 Compared with A2 β-Casein. Adv. Nutr. 2017 Sep; 8(5): 739–748.

[3] Milk Intolerance, Beta-Casein and Lactose. Nutrients 2015 Sep; 7(9): 7285–7297.

[4] 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 behaviour of people with self-reported intolerance to traditional cows’ milk. Nutrition Journal volume 15, Article number: 35. 2015

Special Thanks to Dietitian Kate DiPrima for her contributions to this article.

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