Infant and toddler milks or what you will find in the composition
PhDr. Karolína Hlavatá, PhD.
Breast milk is unique in its composition and thus represents a model that infant formulas try to approximate as closely as possible.
The composition of infant formulas is very strictly monitored and the requirements for their production, information on product packaging, etc. are regulated by legislation.
Infant formula is most often made from cow's milk proteins. In order for cow's milk to serve as the basis of infant nutrition, it must be modified to closely match the nutritional characteristics of breast milk. Examples include adjusting the ratio of whey to casein, supplementing vitamins, or the mandatory addition of docosahexaenoic acid.
Although it may seem that all infant and toddler milks are the same, this is not the case. Just as when choosing suitable foods, it is necessary to read the information on the product packaging. In order for a parent to provide their child with the nutrition that best meets their needs, it is important to understand the basic terms that you may encounter within the context of milk formulas.
There are various types of infant milk formulas on the market that reflect the different needs of children. Examples include anti-reflux milks, milks for allergy sufferers, etc. However, in today's post, we will focus on "classic" milk formulas.
Fats
Fat plays a crucial role in infant nutrition. It provides 40-50% of the baby's energy needs and has a number of other functions. It provides fat-soluble vitamins (vitamins A, D, E, K), essential fatty acids, ensures proper functioning of the digestive tract, is involved in lipid and lipoprotein metabolism, and is an important component of cell membranes. It is essential for proper growth, psychomotor development of the child and optimal functioning of the immune system.
The issue of fat composition in breast milk and infant formulas is very interesting, so let's take a closer look at it.
To understand the context, let's first explain the basic principles.
Fatty acid splitting
The basic building block of fats are fatty acids. Based on the length of the chain and the presence of double bonds, fatty acids are divided into saturated (SAFA = Saturated Fatty Acids) and unsaturated. Unsaturated acids are further divided into fatty acids with one double bond (monounsaturated; MUFA = Mono Unsaturated Fatty Acids) and fatty acids with more double bonds (polyunsaturated; PUFA = Poly Unsaturated Fatty Acids).
Depending on the position of the last double bond, polyunsaturated fatty acids are divided into omega-3 fatty acids and omega-6 fatty acids. These fatty acids are referred to as essential. The body cannot produce essential fatty acids on its own and therefore must obtain them from the diet.
The importance of fatty acids
The fat in breast milk of European women contains 45-50% MUFA, 35-40% SAFA and the remaining 15% PUFA. Manufacturers are striving to achieve similar ratios in formula milk.
Saturated fatty acids and MFGM
Palmitic acid holds a privileged position among saturated fatty acids, accounting for up to 25% of all saturated fatty acids. Anyone interested in a balanced diet may be wondering – saturated fats and healthy? We hear everywhere that we should limit saturated fats in our diet, because in excess they increase blood cholesterol levels and contribute to the development of cardiovascular diseases? It is true, but be careful! A child is not a small adult and a certain proportion of saturated fats is necessary for his successful development. The already mentioned palmitic acid has a positive effect on calcium metabolism, its absorption in the intestine and also softens the stool.
The main sources of palmitic acid are palm and milk fat. The use of palm fat is considered unecological due to the destruction of rainforests, so milk fat is (not only) a more advantageous choice.
Are you wondering why not? This is another impressive piece in the colorful puzzle of breast and infant milk.
MFGM is not a new term in the vocabulary of today's adolescents, but the English abbreviation Milk Fat Globule Membrane. Fats are found in mammalian milk in the form of fat globules (globules; MFG = milk fat globule) enclosed by a three-layer membrane. The core of the globule consists mainly of triglycerides (98%), which, after the globule is split by the child's digestive enzymes, serve as a source of energy. The membrane (i.e. MFGM) has 3 layers and contains a number of bioactive substances that are of great importance for the child's health. Examples of such components are cholesterol, sphingomyelins, phosphatidylcholines, gangliosides, lactoferrin, mucin and others. Their effect is complex and significantly affects the development of the digestive, nervous and immune systems. Proteins in MFGM also have signaling and transport functions.
Whole cow's milk-based infant formulas naturally contain MFGM. Fortifying infant formulas with whole milk is a relatively new development, and studies suggest a possible positive effect on infant health and development. However, more research is needed in this area.
The importance of unsaturated fatty acids
MUFAs account for the largest proportion of fats in breast milk and infant formulas. The main representative is oleic acid. However, despite their abundance, their potential function in infants has not been investigated and their nutritional significance has not been clarified.
In contrast, the importance of PUFA is well known. As already mentioned, they are divided into omega-3 and omega-6 fatty acids. Omega-3 fatty acids include alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The best-known omega-6 fatty acids are linoleic acid (LA) and arachidonic acid (ARA).
PUFAs are part of cell membranes and are therefore essential for the growth and development of the CNS and retina. They also represent the starting materials for the production of many agents that influence inflammatory and immune processes and blood clotting.
DHA content is particularly high in nervous tissue. Fat and PUFA are essential especially in the first two years of a child's life, when growth and differentiation of the central nervous system is most rapid. Current expert studies support the enrichment of infant formulas with omega-3 DHA and omega-6 ARA, however, the legislation requires the addition of only DHA.
The source of DHA in infant formulas is usually fish oil. Overfishing and the resulting devastation of the environment, concerns about heavy metal contamination and possible undesirable odors have led to the search for new sources of DHA. In infant formula, oils from seaweed such as Crypthecodinium cohnii are mainly used.
Carbohydrates and fiber
The main carbohydrate is lactose, similar to breast milk, but other carbohydrates (maltodextrins, gluten-free starches) are also permitted in small quantities. The content of maltodextrins is limited, as they can cause flatulence and infant colic. However, their use in milk formulas has its own significance - they thicken the milk, thereby increasing its satiety and also positively affecting the stability of the mixture.
Prebiotics are indigestible food components that are not digested in the upper digestive tract and are only utilized by bacteria in the colon. Basically serves as food for bifidobacteria and lactobacilli (so-called "good bacteria") in the intestine. The predominance of these bacteria leads to a reduction in the growth of "pathogenic" bacteria and thus to the optimization of the intestinal microbiota, the importance of which for human health is considerable. Importantly, beneficial intestinal bacteria produce short-chain fatty acids, which serve as a source of energy for intestinal cells. Prebiotics also help to absorb important and health-promoting substances, such as vitamins and minerals, protect the intestinal mucosa, have a positive effect on the volume of stool and support immunity and bowel movements.
Several types of prebiotic mixtures are used in infant formula, with the best combination being galactooligosaccharides (GOS) and fructooligosaccharides (FOS) in a ratio of 9:1. The prebiotic mixture used is safe and well tolerated by infants.
Prebiotic oligosaccharides added to infant formulas include the so-called HMO (Human Milk Oligosaccharides). 2'-Fucosyllactose (abbreviation 2-FL) is used in infant formulas. Synthetic 2-FL has the same structure as 2-FL found in human milk. In addition to the described prebiotic effects, it supports intestinal maturation, has a beneficial effect on the intestinal barrier and probably also on the central nervous system.
Probiotics
Probiotic bacteria are also important for optimizing the intestinal microbiota. An example is the lactic acid bacteria Bifidobacterium animalis subsp. Lactis.
Proteins
Cow's milk protein is so-called adapted (the original whey to casein ratio of 2:8 is adjusted to 1:1 or even higher).
Minerals and vitamins
The minimum and maximum amounts of vitamins and minerals for both infant and follow-on formula are set out in Regulation (EU) 2016/127. Regulation (EU) 609/2013 also clearly sets out the forms of these substances that may be used in the production of infant formula. Based on the requirement of the legislation, all infant and follow-on formula contain vitamins C, D. In the case of infant formula, inositol and choline are also added compulsorily. In the case of follow-on formula, these substances are not mandatory, but can be added voluntarily.
Used and recommended literature
1. Nevoral J.: Fats in infant nutrition. Pediatr. praxi. 2018; 19(5): 262–266
2. Bronský J.: The role of prebiotics in the prevention of allergies in children. Pediatr. praxi 2011; 12(5): 359–360
3. Musilová Š, Rada V.: The effect of breast milk oligosaccharides on the intestinal microbiota of infants. Pediatr. praxi 2015; 16(1): 17–19
4. Vyhnánek R.: Milk fat in infant formulas – new findings. Pediatr. praxi 2020; 21(3): 216–218
5. Sýkora J.: The issue of fats in breast milk and infant formula. Pediatr. praxi 2021; 22(3): 189–195
6. Ježek P.: Comparison of milk fat of cow's milk and vegetable fat in infant milk formula and impacts on infant health. Prakt. lékáren. 2022;18(3):187-190
7. Salminen S, Stahl B, Vinderola G, Szajewska H. Infant Formula Supplemented with Biotics: Current Knowledge and Future Perspectives. Nutrients. 2020 Jun 30;12(7):1952. doi: 10.3390/nu12071952. PMID: 32629970; PMCID: PMC7400136.
8. Frühauf P.: Modifications and additions to infant formulas – upgrade of an article from Pediatrie pro praxi 2005; 6. Pediatr. praxi. 2016; 17(2): 92–95
9. https://www.magistra.cz/cs/novinky/2023-04-kojenecke-mleko-kdy-jak-a-co-vlastne-obsahuje?_=m-76
10. https://www.fao.org/fao-who-codexalimentarius/sh-proxy/es/?lnk=1&url=https%253A%252F%252Fworkspace.fao.org%252Fsites%252Fcodex%252FStandards%252FCXS%2B156-1987%252FCXS_156e.pdf
11. https://a0893052e1.cbaul-cdnwnd.com/ccf53c0c8de9f665fefb732f2e88fff2/200000163-4a2514c70f/doporuceni-vyziva-kojencu-a-batolat-2014.pdf
12. Laštovičková J.: Infant milk and legislation. Pediatria (Bratisl.) 2021; 16 (S1): 8-12
13. Ambrożej D, Dumycz K, Dziechciarz P, Ruszczyński M. Milk Fat Globule Membrane Supplementation in Children: Systematic Review with Meta-Analysis. Nutrients. 2021 Feb 24;13(3):714. doi: 10.3390/nu13030714. PMID: 33668227; PMCID: PMC7996302.
14. Zeisel SH, Blusztajn JK. Choline and human nutrition. Annu Rev Nutr. 1994;14:269-96. doi: 10.1146/annurev.nu.14.070194.001413. PMID: 7946521.
