10 magical facts about breast milk

Pendant l’allaitement, le lait maternel constitue une source riche en Immunoglobulines A, en facteurs anti-inflammatoires et en cellules immunologiquement actives nécessaires pour induire à la fois une tolérance aux antigènes non nocifs (antigènes alimentaires ou microbes commensaux bénéfiques) et pour développer une défense immunitaire robuste contre les organismes pathogènes. C’est ce qu’on appelle la " voie entéro-mammaire ", qui se produit lorsque les bactéries du tractus gastro-intestinal de la mère sont transloquées vers les glandes mammaires via les cellules immunitaires [1]. 

La production d’Immunoglobulines A chez le nourrisson est encore très immature. C’est pourquoi leur présence dans le lait maternel permet de protéger le bébé en attendant, une sorte de “parapluie immunitaire”. Les anticorps forment une barrière empêchant la plupart des pathogènes de se lier aux cellules des muqueuses et de l'épiderme [2].

Les immunoglobulines sont présentes en grande concentration dans le colostrum et encore plus particulièrement chez les mères dont les enfants sont nés avant terme.

Pour en savoir plus, retrouvez notre article sur allaitement et immunité.

When babies suckle, the diameter of the nipple increases and a vacuum is created by negative pressure, drawing in fluids including nasal and oral secretions, saliva and milk from the child's mouth into the milk ducts [3].

External bacteria can enter the mammary gland through " retrograde transfer " from sources such as the areolar skin or the infant's oral cavity. The reversal of milk flow towards the breast during feeding may allow microbes to enter and establish themselves in the milk ducts from the infant's mouth. This is known as 'retrograde milk flow' [4]. 

The mammary gland is filled with immune cells that end up in the milk, in order to protect against and respond to the pathogens that baby encounters [5].

During breastfeeding, the baby's saliva interacts with breast milk whilst simultaneously providing precursors to molecules that promote growth. Breast milk interacts via the enzyme Xanthine Oxidase with the newborn's saliva during feeding, producing peroxides (hydrogen peroxide) whose antimicrobial action has been demonstrated. This interaction is also thought to act as a kind of "natural selection" to favour beneficial bacteria, which subsequently colonise the gut.

Milk therefore plays more than a simple nutritional role in mammals, as it interacts with infant saliva to produce a powerful combination of stimulating and inhibitory metabolites that regulate the oral, and therefore intestinal, microbiota [6].

Breast milk contains prebiotics — more than 130 different oligosaccharides, the best known being Human Milk Oligosaccharides — which stimulate beneficial colonisation and reduce colonisation by pathogens in the colon [7].

It also contains Bifidobacteria, which produce organic acids and prevent the growth of pathogenic bacteria [8]. The longer breastfeeding continues, the greater the effects on the microbiome. 
A precious gift when you consider that "the microbiome is said to be "resilient", meaning that by around 2–3 years of age, it will not change much for the rest of life [9]!

In the first few days of life, your baby feeds frequently as they take in very small amounts at a time. They are learning to coordinate sucking, swallowing and breathing. Over time, they take in larger quantities of milk at a sustained frequency: roughly every 2 to 3 hours on average. 

However, they may start wanting to feed much more frequently, for various reasons (growth spurts, illness, etc.) [10] [11]. Cluster feeding is normal and you should not follow a strict breastfeeding schedule - feed your baby on demand and without watching the clock.

La mélatonine, dont le taux augmente dans votre lait la nuit, va aider votre bébé à réguler son horloge naturelle [12].

En plus de la mélatonine, le lait maternel produit la nuit est riche en autres substances comme le tryptophane, un acide aminé qui provoque l’endormissement. C’est un précurseur de la sérotonine, une hormone indispensable pour le cerveau et son développement. Le tryptophane va augmenter le nombre de capteurs de sérotonine. Un bébé allaité la nuit va donc développer plus de capteurs de sérotonine comme l'a montré Darcia Narvaez, une chercheuse américaine [13].

Retrouvez notre article sur allaitement et sommeil pour plus d'informations. 

The composition of breast milk varies according to how the feed progresses, throughout the day and over the course of the breastfeeding period.

At the start of a feed, breast milk is composed of a high proportion of water, lactose and minerals to quench thirst. As the feed progresses, the amounts of proteins and fats increase. Towards the end of each feed, fats become increasingly concentrated in the milk, giving the baby a feeling of fullness [14].

A baby fed on demand can adjust feeds according to their own needs. 

A la naissance, son cerveau ne fait qu’un quart de sa taille adulte. Les bébés ont besoin d’une source continue de carburant pour alimenter leur cerveau, qui va grossir beaucoup les premiers mois. Il a donc besoin de ravitaillements fréquents.

Les études montrent que le DHA un acide gras est bénéfique pour le développement du cerveau du bébé [15], le développement du langage et la vision [16]. Les études montrent même que la concentration en DHA dans le lait maternel varie d’un facteur 10 en fonction de vos apports en DHA alimentaires.

Le taux maternel de DHA baisse pendant l’allaitement, ce qui reflète le passage dans le lait d’un acide gras important pour le développement de l’enfant. Les études montrent même que la concentration en DHA dans le lait maternel varie d’un facteur 10 en fonction de vos apports [17] ! 

Le saviez- vous ? Le snack allaitement Cho-chocolat, la pâte à tartiner Crazy nut contiennent tous 200 mg de DHA, soit la quantité recommandée. Vous pouvez également prendre le complément oméga 3 grossesse, avec 200 mg de DHA par gélule, en plus de notre complément alimentaire post partum pour couvrir vos besoins nutritionnels. 

Breast milk contains stem cells, as does amniotic fluid [18].  

The presence of these cells can most likely be explained by the higher needs of newborns in terms of immune protection, growth, protein synthesis, neurocognitive development and blood vessel development [19]. 

#10 Babies recognise the smell of their mother's milk
 

Babies are born with very limited vision, and the world outside the womb is very stimulating and bright for them. Their sense of smell takes over from their vision, before their sight sharpens over time. The smell of breast milk is very similar to the smell of amniotic fluid, which explains its attractiveness to the newborn [20]. Orientation towards the scents of the mother's breast is an innate response in newborns [21].

Researchers have shown that newborns are very quickly able to distinguish the smell of their own mother's milk from that of another mother's milk. Breastfed newborns were able to distinguish their mother's scent from those produced by unfamiliar breastfeeding women [22].

This is why, given the importance of biological scents for newborns, products that eliminate or mask these signals should be avoided during the perinatal period [23].