After my previous blog about the uniqueness of breast milk (link), it’s now time to dive into infant formula. There are many differences between breast milk and bovine milk. For example, the proteins, vitamin & minerals, lipids, and oligosaccharides all differ. For this reason, although bovine milk is the basis of infant formula, many changes need to be made to create infant formula.
For the proteins, the major difference is the lower protein level, especially of casein (the cheese protein), in breast milk, while it contains relatively high whey protein levels. So to make infant formula, whey protein is used as the basis, to make a product with lower protein content, with a concomitant shift from casein to whey protein.
One of the challenges of using whey as basis for infant formula, however, is that it contains much more minerals than breast milk. And for the infant kidneys, a lower mineral intake is important. Whey is therefore not used as-is, but after a step of mineral reduction, after which more pure whey protein is obtained. For other minerals and vitamins, several differences exist that are compensated by adding these as separate ingredients.
When it comes to lipids, more unsaturated fatty acids are present in breast milk. Therefore, plant oils are used, as these naturally contain more unsaturated fatty acids. Different plant oils, sometimes mixed with bovine milk fat, are used to reflect breast milk lipids best.
Finally, the oligosaccharide content is very different, with much higher contents in breast milk. In the past years, this was usually compensated by adding an oligosaccharide mixture (called GOS/FOS). Although this compensated the oligosaccharide level, GOS/FOS are different oligosaccharide structures. Recently, the production of a oligosaccharide structure that is also present in breast milk became possible.
This is however not the end. We still learn more-and-more each day about breast milk composition, its complexity and its beneficial effects. Challenges will thus remain to keep updating infant formula in future, to minimize these differences.
Kasper Hettinga, November 2017