On average, each Australian consumes
105 litres of milk in a year.1
Milk, along with other dairy products, is a rich source of calcium and other minerals, protein and
vitamins and is recommended as part of a healthy diet.2 For some people, however, milk consumption
can have adverse health impacts. Here you can learn more about milk types, the process of milk
digestion and some of the conditions associated with adverse reactions to milk.
The components of cows’ milk
Cows’ milk contains protein, fat, carbohydrate (namely lactose) as well as vitamins and
minerals in amounts that can vary considerably between different cow breeds and also
between cows of the same breed and herd.3,4
Basic components of cows’ milk
(mean values/100 mL)5
The process of digestion
releases the nutrients from
cows’ milk in a usable form.
What is beta-casein?
of the total protein in
cows’ milk is beta-casein6
Beta-casein occurs as one
of two genetic variants

A1 and A26
Regular cows’ milk contains a mixture of A1 and A2 beta-casein. Existing and emerging research is
exploring the possible health impacts of cows’ milk A1 beta-casein. a2 Milk™ contains only the A2 beta-casein protein.COMPLETED
Milk digestion and adverse milk reactions
Milk digestion
and absorption
The gastrointestinal system
processes ingested milk into
its molecular forms (digestion)
for absorption and distribution
by the circulatory system.3,4
Learn more
Digestive conditions
& milk intolerance
Some digestive conditions – such as
inflammatory bowel disease, irritable
bowel syndrome and coeliac disease
– can affect the ability to digest milk
and absorb nutrients, resulting in
milk (or lactose) intolerance.
Learn more
Adverse milk
Adverse milk reactions may be
immune-related (ie milk allergy)
or of metabolic origin (eg lactose
intolerance and A1 beta-casein
protein intolerance).7,8
Learn more
A1 beta-casein
protein intolerance
There is evidence that cows milk
A1 beta-casein protein may stimulate
gastrointestinal symptoms of
intolerance in some people, through
the action of the A1 beta-casein
derived opioid peptide, beta-
casomorphin-7 (BCM-7).9,10
Learn more
Adverse milk reactions
diagnostic algorithm
Use this tool to help to identify A1
beta-casein intolerance and lactose
intolerance in patients with symptoms
following milk intake.
Go to algorithm
a2 Milk™ may assist some people with
milk-mediated digestive symptoms
Although milk and other dairy products are recommended as part of a healthy diet, most Australians
consume only about half the recommended quantity.2 Some people who report intolerance symptoms following milk intake may benefit from a2 Milk™,
which is produced by cows that do not carry the gene for A1 beta-casein. Because a2 Milk™ is free
of A1 beta-casein, some people may experience differences in gastrointestinal symptoms when
substituting it for regular cows’ milk.9,10
References: 1. Dairy Australia consumption summary. www.dairyaustralia.com.au/Markets-and-statistics/Production-and-sales/Consumption-Summary.aspx (accessed 10 November 2016). 2. National Health and Medical Research Council (2013) Australian Dietary Guidelines. Canberra: National Health and Medical Research Council. www.eatforhealth.gov.au/guidelines (accessed 25 August 2016). 3. Vander A et al. (2001). Human physiology: The mechanism of body function. 7th ed. Boston, MA: McGraw-Hill. Chapter 17. pp: 553–591. 4. Garrow JS, James WPT (eds). (1993). Human nutrition and dietetics. 9th ed. London: Churchill Livingstone. Section 1. pp: 24–262. 5. Cows’ milk values per 100 mL taken from Food Standards Australia New Zealand (FSANZ) NUTTAB database and Foodworks supermarket. 6. Formaggioni P et al. Universiti degli Studi de Parma, Annalli della Facolta di Medicina Veterinaria 1999; Vol XIX:127–165. 7. Boyce JA et al. J Allergy Clin Immunol 2010; 126: S1–S58. 8. Australasian Society of Clinical Immunology and Allergy (ASCIA). Information sheet: Food allergy clinical update for health professionals. 2016. www.allergy.org.au/patients/food-allergy/cows-milk-dairy-allergy (accessed 28 August 2016). www.allergy.org.au/health-professionals/papers/food-allergy (accessed 28 August 2016). 9. Pal S et al. Nutrients 2015; 7: 7285–7297. 10. He M, et al. (2017). Effects of cow’s milk beta-casein variants on symptoms of milk intolerance in Chinese adults: a multicentre, randomised controlled study. Nutr J. 16:72.