What is so sad is that advertising of artificial infant milk, in which claims are made about additives, encourage parents to switch to these products and stop or reduce breastfeeding. What that means is that the babies then receive greatly REDUCED prebiotics and less of other protective factors. Let's just look at one major component of human milk, oligosaccharides, which serve as one of the prebiotics in breastmilk. They are there in a variety of different sorts, and they are there in a large amount.
1) The lowest count I've seen of the variety of oligosaccharides in human milk is 130. So that means at least 130. When oligosaccharides are added artificially to toddler milks and artificial baby milks for younger babies ("formula"), only a very few of these can be added. Think of these additives as more of a condiment than as the main course, i.e. a small amount.
2) Oligosaccharides are the third most common ingredient in human milk. In artificial infant milks ("formula") and toddler milks there are only traces, and when some brands use them as additives in their products, they are nowhere near as high a proportion or as wide-ranging in type as they are in human milk. Switching from breastmilk to factory-made milks actually reduces the amount and variety of oligosaccarides the baby eats. (The advertisements don't admit this.)
Sadly, I see people leaving supermarkets and in Post Offices with a large number of cans of an Australian-made artificial baby "formula" that they are sending - in bulk - to family and friends in China. They really care about the babies and want to avoid the tragedy of the contaminated artificial "formula" of a few years ago - and slick marketing constantly tells them that these products are " better". It is so sad to see these products sent at great cost and the babies getting a food that doesn't have the important and protective ingredients that come naturally (and for free) in breastmilk.
I have put some references in an earlier post and you might like to check them out. Here's another one:
_ Table 2 in, Perrin MT et al. Journal of Human Lactation 2013; 29(3): 341-349. This useful table is on p. 342.