There are numerous known benefits to breastfeeding an infant as opposed to using formula. Breastmilk is safe, nutritionally optimal, contains antibodies and can be easier in hygiene terms than bottle feeding.

Improving breastfeeding rates globally holds importance because it is one of the most effective ways to support child health. The World Health Organisation (WHO) recommends that infants exclusively breastfeed until 6 months, when complementary foods can be added, and can continue breastfeeding alongside the introduction of food until 2 years plus (1).

The first 1000 days of life from conception right the way through to 2 years is key in child growth, immunological, metabolic and gut microbiome development. Therefore, the WHO recommends continuing breastfeeding after the initial 6 months and highlights why maternal nutrition is so important during pregnancy and lactation (2).
While there can be challenges involved in breastfeeding, and a mother being able to breastfeed, there are many advantages for mother’s and infant health (3). The benefits will be discussed in this article.

Biologically speaking, pregnancy and lactation are part of the reproductive cycle, yet many challenges are faced when it comes to breastfeeding. In the poorest countries, late initiation of breastfeeding is an issue. In middle-income to high-income countries, short overall duration of breastfeeding is the predominant challenge (4).

Breastmilk provides an infant with the complete nutrition required up to six months and protection against potential infectious pathogens. There are short-term and long-term health outcomes associated with breastfeeding. This includes reduced risk of infant mortality in the short-term and reduced risk of type 2 diabetes and obesity, as well as positive cognitive outcomes in the long-term (4). Additionally, there are maternal benefits to breastfeeding, including the reduced incidence of breast and ovarian cancer and improved birth spacing (5).

Nutritional benefits of breastfeeding

The nutritional composition and the non-nutritive bioactive factors of human breastmilk are uniquely suited to the human infant for healthy growth and development. The nutritional components, including macronutrients and micronutrients come from maternal stores, the maternal diet and can be influenced by body composition (6).

Some vitamins can be in lower supply than others, such as vitamin D, and it is recommended that breastfeeding mothers take a vitamin D supplement if they are not exposed to much sunlight (6). Vitamin and mineral content of breast milk appear to be positively correlated with maternal intake. However, macronutrient data is unclear as it is based on indirect relationships (7). The high bioavailability of minerals and the optimal protein content of breastmilk makes it suited to immature digestive systems of infants (8).

The bioactive components in human milk include immune factors, metabolic hormones and prebiotic oligosaccharides, to name a few. Human milk oligosaccharides (HMO) are the prebiotic oligosaccharide components of breast milk that selectively encourage the growth of beneficial organisms, including good bacteria (9).

Some vitamins can be in lower supply than others, such as vitamin D, and it is recommended that breastfeeding mothers take a vitamin D supplement if they are not exposed to much sunlight (6). Vitamin and mineral content of breast milk appear to be positively correlated with maternal intake. However, macronutrient data is unclear as it is based on indirect relationships (7). The high bioavailability of minerals and the optimal protein content of breastmilk makes it suited to immature digestive systems of infants (8).

HMOs are the 3rd largest component of human milk and there are more than 200 HMOs present. Their diversity and complexity contribute to the growth and development of the infant’s gut microbiota (9). The growth of microorganisms in the infant’s gut from birth - or maybe even in utero - begins the growth and development of the gut microbiota. The growth of the infant’s gut microbiota and the composition of breastmilk supports the development of the infants immune and metabolic function, amongst other health benefits (6).

Breastfeeding benefit to the gut microbiome

HMOs play an important part in the development of the gut barrier and normal immune responses (9). However, the infant’s gut is first colonised by bacteria from the mother by contact through mode of delivery and in-utero. There is a rich presence of probiotic bacteria (bacteria that elicits a health benefit on the human host) in human milk (10).

The presence of bacteria in human milk is thought to be one way that the infant gut is colonised with beneficial bacteria. The probiotics in human milk are beneficial to breastfeeding mothers because the probiotics improve mammary health (10). There appears to be a transmission of bacteria from mother to infant and vice-versa. The probiotic bacteria in the milk microbiome comes from the mammary glands by contamination from the skin microbiome, and from the maternal gut microbiome through extraintestinal transport (11).

Probiotics given to breastfeeding women reduce recurring mastitis, the recurring inflammation and infection of the mammary glands and alter the milk microbiome providing health benefits for the mother and infant (12).


Human milk bacteria have several roles in infant health, including reduced incidence and severity of infection due to competitive exclusion and the production of antimicrobial compounds. Gut bacteria are the earliest and most important stimulus for the gut associated lymphoid tissue (GALT) which is approximately the 70% of the immune system that is present in the gut (13).

The individual health and gut microbiome of lactating women can be beneficial to breastfed infants. Future research could determine if the modulation of the maternal gut microbiome can pass on health benefits to infants through breastfeeding (13).
With that in mind, could maternal supplementation with prebiotics provide transferable health benefits to the infant?


The HMOs stimulate growth of the beneficial bacteria. This aids the maturation of the gut microbiota and the immune response. Specific HMOs stimulate the growth of specific bacteria such as bifidobacteria. Low levels of bifidobacteria later in life are associated with atopic disease, therefore stimulating growth of specific bacteria is important for the infant’s health (14).

Exclusive breastfeeding for at the least the first two months of life is associated with a more stable gut microbiota and reduced diarrhoea-associated microbial dysbiosis. The benefit of exclusive breastfeeding is that it maintains the development trajectory of the gut microbiota, allowing for the optimal establishment of the gut microbiota and subsequently the immune system (15).

Breastfed infants have a gut microbiota dominated by Bifidobacteria and Lactobacillus due to the presence of HMOs, whereas infants fed formula without pre- or probiotics have a gut microbiota that resembles that of older children. Children with higher abundance of bifidobacteria are reported to have a low risk for development of allergies. Additionally, children with the lowest abundance of bifidobacteria, Akkermansia, and Faecalibacterium are more at risk of atopy and asthma (16). The development of immune function and a reduced allergy risk gives good reason for encouraging breastfeeding for infants during the first six months of life.

Conclusions

Research continues to demonstrate the benefits of breastfeeding for infant and maternal health. Breastfeeding is considered the optimal feeding mode for infants and if possible, the shift away from alternatives to human milk should be encouraged.

There are specific cases where breastfeeding would not be recommended but with the associations to positive health outcomes and the growing evidence base, breastfeeding awareness should be a priority.