Milk is one of the richest food sources of calcium, which is necessary for strong bones and healthy teeth. One cup of milk provides between a half to a third of calcium’s recommended daily intake for a child (aged between 1-11 years) and around one third to a quarter of that for an adult. As calcium is present only in very small amounts in most common foods, it may be difficult for individuals who are restricted in their intake of milk and milk products to obtain the recommended amount. For more information on the importance of calcium in the diet, go to the government website www.nrv.gov.au. Milk is also naturally packed full of other essential vitamins and minerals, like A, B2, B3, B6, B12, D, E, K, magnesium, phosphorus, potassium, zinc and selenium.
Milk also provides a complete source of protein (both whey and casein) and is a natural source of carbohydrate for energy.
The two main types of milk proteins are the casein and the whey proteins. These make up to 80% and 20% of the protein content of cows’ milk respectively. Other proteins present at low levels in milk include antibodies and iron carrying proteins.
Beta-casein makes up about one third of the total protein content in milk. All cows make beta-casein but it is the type of beta-casein that matters. There are two types of beta-casein: A1 and A2. They differ by only one amino acid. Such small differences in the amino acid composition of proteins can result in the different protein forms having different properties.