Cow’s Milk – a Cornerstone Dietary Staple

Let’s start with cow’s milk, then move onto A2 Protein Milk. One of the cornerstones of the Australian Dietary Guidelines and most government dietary guidelines around the globe is the inclusion of dairy foods such as milk (1). The reason for this is that milk provides a range of essential vitamins and minerals and is an excellent source of high-quality protein. In fact, a number of studies have shown that milk intake is a marker for overall diet intake quality, largely because of its rich provision of nutrition (2-4).  In short, a cup of cow’s milk provides a big bang for your nutrition dollar.

The very high calcium content of milk and dairy foods per serve has largely driven the recommendation for including dairy foods as part of a healthy diet. The reason for this is that since the agricultural revolution, when hunter-gatherer people shifted from eating plant foods high in calcium to consuming plant foods relatively lower in calcium, the major food source of calcium shifted to dairy milk and its products (1).  So, milk and dairy foods today are our major source of calcium and other important nutrients.

As well as calcium, cow’s milk provides many other nutrients (Table 1). Cow’s milk is a good source of high-quality protein, riboflavin, vitamin A (full fat milk only), magnesium, iodine, phosphorus and zinc (5).  Three dairy serves per every day will allow most people to reach their daily calcium needs but also makes an important contribution to the recommended daily intakes of these other essential nutrients.  So, the next time you think to grab a quick snack, why not make it milk (or a smoothie)?

Table 1: Nutrient composition of cow’s milk

  Cow milk (regular) 250 mL serve (1 cup) % Daily Intake (based on 8700 kJ/day) Cow milk (skim)  250 mL serve (1 cup) % Daily Intake (based on 8700 kJ/day)
Energy (kJ) 733 8.4 % 368 4.2 %
Protein (g) 8.8 18.0 % 9.3 18.6%
Total fat (g) 8.8 12.9% 0.25 0.4%
Carbohydrate (g) 15.8 5.2% 12.5 4.0%
Calcium (mg) 268 33.5% 302 37.8%
Phosphorus (mg) 230 23% 250 25%
Riboflavin (mg) 0.5 29.4% 0.5 29.4%
Iodine (mg) 58 38.6% 38 25.3%
Magnesium (mg) 25 7.8% 30 9.4%
Zinc (mg) 1.0 8.3% 0.8 6.7%
Vit. A (μg retinol equivalents) 125 16.7% 0.0 0.0%

Source: Dairy Australia. Proximate Composition of Australian Dairy Foods. Your guide to the nutritional content of Australian Dairy Foods. Note: One glass (250ml) of milk is equal to 1 serve of dairy.

What is A2 Protein and Why Drink A2 Protein Milk?

Cow’s Milk has a number of different proteins, including whey proteins and casein proteins. Of the casein proteins, one of the major sub-groups is called the beta-caseins. Of the beta-caseins, there are 2 types: A2 beta-casein and A1 beta-casein types (Figure 1).

Figure 1: Major cow’s milk protein groups, showing beta-casein A2 and A1 sub-groups

People digest these A2 and A1 beta-caseins differently, because these 2 beta-casein protein types have different protein structures (6). It seems that because of these differences, human studies including Australian and Chinese participants have shown that some people do not feel digestive discomfort when they have A1 Protein free cow’s milk, such as A2 Protein Milk (7-11).

Of course, A2 Protein Milk still has lactose in it, so for those who are lactose intolerant, they will still need lactose free or lactose reduced milk.

While the reasons for all this are still being investigated by researchers, the main take home point is that there is another dairy milk alternative available for people who prefer A2 Protein type milk.

Do all cows produce A2 Protein in their Milk?

No, not all cows produce A2 Protein in their milk.

  • Some dairy cows have the genetic ability to naturally produce only the A2 Protein in their milk;
  • Other dairy cows have the genetic ability to produce only the A1 Protein in their milk;
  • Still other dairy cows have the genetic ability to produce both the A1 and A2 Proteins in their milk.

All this means that an ordinary dairy cow herd produces milk which contains both the A1 and A2 Protein in its milk.

A2 Protein Milk is different to the milk produced by an ordinary dairy herd, because it is naturally A1 Protein free and can only come from cows which naturally produce only the A2 Protein type and not the A1 type (6). Why not give it a try?

References

  1. Weaver CM. How sound is the science behind the dietary recommendations for dairy? Am J Clin Nutr. 2014;99(5 Suppl):1217S-22S.
  2. Coudray B. The contribution of dairy products to micronutrient intakes in France. J Am Coll Nutr. 2011;30(5 Suppl 1):410S-4S.
  3. Fulgoni V, 3rd, Nicholls J, Reed A, Buckley R, Kafer K, Huth P, et al. Dairy consumption and related nutrient intake in African-American adults and children in the United States: continuing survey of food intakes by individuals 1994-1996, 1998, and the National Health And Nutrition Examination Survey 1999-2000. J Am Diet Assoc. 2007;107(2):256-64.
  4. Ranganathan R, Nicklas TA, Yang SJ, Berenson GS. The nutritional impact of dairy product consumption on dietary intakes of adults (1995-1996): the Bogalusa Heart Study. J Am Diet Assoc. 2005;105(9):1391-400.
  5. Gaucheron F. Milk and dairy products: a unique micronutrient combination. J Am Coll Nutr. 2011;30(5 Suppl 1):400S-9S.
  6. Scientific Report of EFSA prepared by a DATEX Working Group on the potential health impact of ß-casomorphins and related peptides. EFSA Scientific Report (2009). 231, 1-107. Cited Nov. 2018. URL: http://edepot.wur.nl/8139
  7. Ho S, Woodford K, Kukuljan S, Pal S. Comparative effects of A1 versus A2 beta-casein on gastrointestinal measures: a blinded randomised cross-over pilot study. Eur J Clin Nutr. 2014;68 (9):994-1000.
  8. 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. Nutrition Journal. 2016;15:35. Epub 2016/04/04.
  9. 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. Nutrition Journal. 2017;16(1):72.
  10. Brooke-Taylor S, Dwyer K, Woodford K, Kost N. Systematic Review of the Gastrointestinal Effects of A1 Compared with A2 beta-Casein. Adv Nutr. 2017;8(5):739-48.
  11. Pal S, Woodford K, Kukuljan S, Ho S. Milk Intolerance, Beta-Casein and Lactose. Nutrients. 2015;7(9):7285-97.