Benefits for babies

How will breastfeeding help my baby?

Breastfeeding has many benefits for babies, from preventing acute and chronic disease to improving brain development to lowering obesity rates. Breastfeeding provides food security and reduces babies’ stress. Breast milk is unique to each mother and has a wide range of components that work together to promote good health and optimal development.

A) Benefits for babies and young children

The benefits of breastfeeding  work at many levels and come from both the activity of breastfeeding and from breast milk. The latter is much more than just food; it is a reactive biological system made of a large variety of compounds that can affect the baby’s growth, fight disease-causing microbes, and modulate the baby’s response to challenges.

Breastfeeding helps the baby adjust to living outside of the mother’s body, supports optimal growth and development, and programs the baby for future good health (Donovan 2006). Some of the benefits of breastfeeding include:

There are benefits for the smallest premature babies and for busy toddlers and children. Benefits extend to the society in which the baby lives and to the environment.

B) Benefits at different levels

1. Benefits at the macro level

At the large or “macro” level, feeding at the breast provides the comfort of a familiar environment with warm milk always at the right temperature, the mother’s unique heartbeat and voice, and the smell of her breast and milk, all of which quickly calm a baby.

Compared to bottle-fed babies, breastfed babies tend to be less obese. The differences in feeding from the breast and from a bottle may play a role. Breastfed babies control their intake by only getting milk when they stimulate the let-down reflex by sucking. Bottle-fed babies have less control over how much milk they take in, as the milk flows steadily as soon as they are latched onto the bottle nipple (Wood 2016).

2) Benefits at the micro level

At the “micro” level, the baby and mother are connected through hormonal and microbial signals that help to protect and program the baby. For example, breast milk can be called chrononutrition as chrono means related to time and as the levels of some breast milk components change during the day and night. These variations may be providing nutrients when they are most needed by the baby, teaching and supporting the baby’s internal clock, and synchronizing the mother’s and baby’s body rhythms.

Differences are even seen inside of the baby’s genes (chromosomes).   

C) Examples of beneficial breast milk components

Breast milk has been called nature’s first functional food (Gura 2014). It has a wide range of components that work together to help the baby thrive (Smilowitz  2014).  Three fascinating examples are microRNA, human milk oligosaccharides, and lactoferrin.

1) MicroRNA 

MicroRNA consists of a small piece of ribonucleic acid (RNA) and is present in small pieces of cells (exosomes) within breast milk. There are at least 1,400 different types of microRNA in breast milk (Benmoussa 2019). It survives the trip through the acidic stomach and is absorbed by the cells of the baby’s bowel (Kahn 2018).  MicroRNA can control  the expression of the baby’s genes and is thought  to have a role in several biological processes, including (Leroux 2021):

  • The response and development of the immune system 
  • The development of the nervous and digestive systems 
  • Communication between human cells and the gut microbiome
  • Cell life  and function
  • Muscle cell development 
  • Stem cell development 

In addition, there is evidence that microRNA can keep viruses from replicating (Leroux 2021).

2) Human milk oligosaccharides 

Human milk oligosaccharides (HMOs) are specialized compounds made up of sugar molecules that are linked together. There are over 200 types of HMOs and they are present in large amounts and in breast milk.

HMOs have a wide range of functions including:

  • Supporting the growth of a healthy gut microbiome
  • Protecting the baby from:
    • Infection
    • Inflammation
  • Providing nutrients for the baby’s developing brain 

HMOs are unique to each mother and their amounts change over time (Newburg 2013). Colostrum, the first form of milk, has three times the concentration of HMOs of mature breast milk to support the quick growth of helpful microbes and keep out disease-causing ones thereby protecting the vulnerable new baby (Smilowitz 2014) .

When HMOs help good microbes grow, they act as prebiotics.

3) Lactoferrin  

Lactoferrin is a molecule that is part protein and part sugar. It is present in the milk of a number of other animals including cows, goats, pigs, and mice but not in the milk of dogs, rats, or rabbits (Masson 1971). Lactoferrin of different species has different structures and actions (Conesa 2008). Lactoferrin is found in large amounts in human colostrum and mature milk. Indeed, lactoferrin amounts in mature breast milk are 200 times those found in cow’s milk (Neville 2000).

Human lactoferrin has been found to have many functions that benefit the health of the baby, including: (Mastromarino 2014; García-Montoya 2012; Legrand 2008; Patel 2018):

  • Supporting bone health  
  • Supporting the growth and maturation of the cells of the gut  
  • Stopping the growth of disease-causing microbes by:
    • Killing them
    • Preventing the buildup of bacterial clusters (biofilms)
    • Holding onto iron and keeping it from disease-causing bacteria that need iron to grow  
  • Supporting the development of a healthy gut microbiome
  • Having cancer-fighting properties
  • Promoting healthy development of the immune system

Lactoferrin levels are highest after the baby’s birth, when the baby is most vulnerable, and decrease over the first year of the baby’s life (Yang 2018).

The milk of mothers whose babies are born premature has more lactoferrin than the milk of mothers with full-term babies, and the levels remain higher for the first two months after the premature baby’s birth (Turin 2017). This may prevent infection in these vulnerable babies.

D) Breast milk is unique to each mother-baby pair

1) The breast milk of each mother is different 

Breast milk is unique, not only between each species of mammal but also between mothers:

  • In the type of beneficial microbes found in the milk.
  • In the type of HMOs.
  • In the genetic makeup of cells and microRNA.
  • In the level of activity it can direct at various disease-causing microbes.
  • In the amount of breast milk fat.
  • As different foods in the mother’s diet flavour the smell and taste of the milk.

2) Breast milk changes as the baby grows

As the baby grows, milk changes from colostrum, to transitional, mature, and weaning milk. All of these variations provide nutrients when they are most needed by the baby.

3) Breast milk responds to the condition of the baby 

Breast milk has been described as a vehicle of communication between the mother’s and baby’s immune systems by providing routine protection such as antibodies and actively adjusting the baby’s immune system. For example, when mothers or their babies get sick, breast milk has more white blood cells to fight infection. This response is stronger when mothers are exclusively breastfeeding.

References

Benmoussa A, Provost P. Milk MicroRNAs in Health and Disease. Comprehensive Reviews in Food Science and Food Safety. 2019;18:703-22

Conesa C, Sánchez L, Rota C, et al. Isolation of lactoferrin from milk of different species: calorimetric and antimicrobial studies. Comp Biochem Physiol B Biochem Mol Biol. 2008 May;150(1):131-9

Donovan SM. Role of human milk components in gastrointestinal development: Current knowledge and future needs.  J  Peds. 2006;149(5): S49-S61 

García-Montoya IA,  Cendón  TS, Arévalo-Gallegos S, et al. Lactoferrin a multiple bioactive protein: an overview.  Biochim  Biophys  Acta. 2012 Mar;1820(3):226-36 

Gura T. Nature's first functional food. Science. 2014 Aug 15;345(6198):747-9

Kahn S, Liao Y, Du X, et al. Exosomal  MicroRNAs in Milk From Mothers Delivering Preterm Infants Survive in vitro Digestion and are Taken up by Human Intestinal Cells. Mol  Nutr  Food Res. 2018 Apr 12:e1701050 

Legrand D, Pierce A,  Elass  E, et al. Lactoferrin structure and functions. Adv Exp Med Biol. 2008;606:163-94 

Leroux C, Chervet ML, German JB. Perspective: Milk microRNAs as Important Players in Infant Physiology and Development. Adv Nutr. 2021 May 22:nmab059

Masson PL, Heremans JF. Lactoferrin in milk from different species. Comp Biochem Physiol B. 1971 May 15;39(1):119-29

Mastromarino P, Capobianco D, Campagna G, et al. Correlation between lactoferrin and beneficial microbiota in breast milk and infant's feces. Biometals. 2014 Oct;27(5):1077-86

Neville M. Lactoferrin Secretion into Milk: Comparison between bovine, murine and human milk. J. Anim. Sci. 2000;78(Suppl3):26-35

Newburg DS.  Glycobiology of human milk.  Biochemistry (Most).  2013 Jul;78(7):771-85 

Patel AL, Kim JH.  Human milk and necrotizing enterocolitis. Semin  Pediatr  Surg. 2018 Feb;27(1):34-38 

Smilowitz JT, Lebrilla CB, Mills DA, et al. Breast milk oligosaccharides: structure-function relationships in the neonate.  Annual review of nutrition.  2014;34:143-169 

Turin CG, Zea-Vera A, Rueda MS, et al.; NEOLACTO Research Group. Lactoferrin concentration in breast milk of mothers of low-birth-weight newborns.  J  Perinatol. 2017 May;37(5):507-512 

Wood CT, Skinner AC, Yin HS, et al. Association between bottle size and formula intake in 2-month-old infants. Acad Pediatr. 2016;16(3):254–9

Yang Z, Jiang R, Chen Q, et al. Concentration of Lactoferrin in Human Milk and Its Variation during Lactation in Different Chinese Populations. Nutrients. 2018 Sep 5;10(9). pii: E1235