Cow’s milk vs human breast milk – how do they compare?

What is cow’s milk?

Like humans, and all other mammals, cows are prolific producers of milk, which they use to nurse their offspring. They are so good at it, that humans have made an industry of it.

However, the milk in products that we use is different from what comes from the animal (whole milk). It needs to go through different processes to make it safe to consume.

The main steps are:

  • Pasteurization: heating of the milk, to kill any bacteria or viruses.
  • Homogenization: reducing the fat content and making it a more regular consistency, so it doesn’t separate out
  • Skimming: removing the top layer of fats, and leaving the protein behind. This is how low-fat milk is made.
  • Ultrafiltration: some milks are passed through very fine filters, which purifies it and makes it last longer in liquid from
  • Drying: this removes the moisture from the milk, to leave a dry powder, which has a long life in storage.

What’s in it?

Like human milk, cow’s milk contains more than 80% water, with the rest as fats, protein, carbohydrates (lactose), vitamins and minerals[1]. So, it is a complete package of nutrients. Whole cow’s milk, like human milk, also contains living factors that help with stimulating the immune system.

The protein in milk classified into two main groups – whey and casein. Casein is the part of milk that becomes thicker, when it is milk is made into cheese. Casein helps with the absorption of calcium and phosphorus.

Whey protein is more soluble and contains a variety of factors including lactoferrin. It is also easier to digest in tiny tummies. Both casein and whey contain a full profile of essential amino acids.

How are they different?

Cow’s milk has the same basic composition as human milk, but the proportions are different. Cow’s milk is higher in casein versus whey protein (80:20) compared to human milk (60:40) [2]. Here are some of the main differences:

  Cow’s milk Human milk
Total protein 3-4% 1-2%
Total fats 3-5% 2-4%
Lactose (carbohydrate) 4-5% 6-7%
Whey/Casein 80/20 60/40
Calcium[3] (mg/litre) 120 28
Phosphorus[4] (mg/litre) 52 9

Infant formulas made from cow’s milk are modelled off of human milk in many respects. One example is through enriching for whey protein. Also, the processes to make milk safe for human use mean that additional micronutrients usually added, except for calcium and phosphorus, which are higher in cow’s milk.

What do health authorities say?

Although regulators still maintain that breast milk is the most complete form of nutrition, the use of cow’s milk products containing complete nutrient profiles, especially including iron, are recommended by health authorities, such as NHMRC [5].

The World Health Organization recognizes cow’s milk as a source of essential nutrients, and an important source of energy, high-quality protein and fats [6]. This is especially the case in countries where breastmilk is of lower in nutrient quality, due to malnutrition of the mother [7].