Scientific studies prove that breastfed infants suffer less infections than non-breastfed ones because the mother’s milk contains antibodies and nucleotides that help infants build up their immune system. For example, breastfeeding is connected with lower rates of gastrointestinal and respiratory infections, as well as a healthy maturation of the gut.
Immediately after birth, a mother’s breast releases pre-milk or colostrum. Rich in antibodies and low in fat, it supports the baby’s natural basic immunity. Also, it contains nutrients which have a positive effect on digestion. After about two days, the fatty and high-energy transition-milk flows in. By the end of the second week, mature breast milk is formed, providing the child with everything needed for its healthy development.
A baby’s energy requirement per kilogram of body weight is about three times higher compared to adults. The baby’s neural pathways are growing and the digestive and immune systems are still maturing. In order to develop well, the child needs all nutrients in optimal composition and breast milk provides the perfect mix.
Breastfed children benefit from several advantages compared to those not breastfed, which even extend to adulthood. Breastfeeding is connected with lower rates of allergy, overweight and obesity, and improved mental development. Clinical studies clearly show that breastfeeding decreases the risk of many diseases and pathologies such as gastrointestinal infections, middle ear inflammatory infections (otitis media), respiratory infections, type-II diabetes, and high blood cholesterol (lipid metabolism).
Breastfeeding promotes mother-child bonding but also has great advantages for the health of the mother herself, such as a faster recovery of the uterus after giving birth. In the long term, it reduces the risk of developing breast and ovarian cancer, and is also associated with lower rates of cardiovascular diseases.
Breast milk contains active components which play an extremely important role in the function and development of an infant’s immune system. One of the most relevant of these components are nucleotides. Nucleotides serve as monomers of nucleic acids such as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), while other nucleotides, such as adenosine triphosphate (ATP), transfer chemical energy and act as cofactors for signal transduction reactions. Other nucleotides are involved in the synthesis of proteins, lipids and carbohydrates. Breast milk contains free nucleosides, free nucleotides, RNA and DNA. The concentration of the “total potentially available nucleotides” in breast milk is around 10.5-11mg/100kcal.
Nucleotides have been studied in infants with respect to their effect on antibody titres after vaccination and the incidence of infections and diarrhoea (Yau et al, 2003). They promote a positive immune response and are also involved in other functional roles such as the maturation of the gut.
What is probably even more important is the practical ability of breast milk to protect against infections due to the presence of specific antibodies in breast milk. The positive effect of these antibodies manifests itself in an increased resistance against gastrointestinal infections (Agostoni et al, 2009).
Similarly, convincing data exist related to the protective effect of breast milk regarding respiratory infections. In a meta-analysis report, Horta et al. (2013) demonstrate that for the baby breastfeeding leads to “levels of protection around 30% for morbidity, about 50% for hospital admissions and about 60% for mortality, suggesting that breastfeeding affects not only the incidence but also the severity of these infections”.
These are only a few examples of overwhelming data that prove that breastfeeding has a positive effect on the immune status of an infant. The level of protection against infections provided by breast milk is unique and helps to ensure healthy development for babies all around the world.back
Breast milk constitutes an extremely dynamic system and its composition changes with the individual needs of the baby – not only during its long-term development, but also short term as a response to milk removal by the infant.
During the first few days after birth the “pre-milk” or “colostrum” is expressed, which is characterised by a particularly high concentration of immunological components such as secretory immunoglobulin A (IgA), lactoferrin and leukocytes (white blood cells), as well as various growth factors (Ballard and Morrow, 2013). Subsequently, colostrum changes into protein and fat-rich “transitional milk” which lasts until the end of the second week after birth and supports the needs of the growing infant during this period. After four to six weeks, breast milk is finally considered fully mature.
Moreover, breast milk also changes dynamically during feeding. Initially, it adopts the composition of less fatty and more lactose enriched foremilk. Then, later during feeding, a fattier hind milk follows. The longer the intervals between the individual feedings are, the more foremilk accumulates.
Additionally, it has also become obvious that breast milk even changes between feedings (Hassiotou et al, 2013). A study conducted by the aforementioned authors shows that in many cases, breast milk which is expressed after a longer period of time following a feeding has a higher fat and cell content compared to breast milk sampled immediately after the end of the respective feeding. A possible reason for the differing fat concentration could be a natural control of the baby’s appetite.
These complex dynamics result in a truly individualised breast milk composition, which optimally fulfils the nutritional needs of each child in every phase of its development.back
The first six months after birth represent a critical time period for infants. Crucial developmental milestones have to be reached and all necessary nutrients for healthy growth have to be provided in liquid form. On average, infant energy requirements are approximately three times higher than those of an adult, which stresses the absolute importance of proper nutrition. Breast milk does not only ensure the right energy level, but also has to provide all the necessary micro and macronutrients.
In adjustment to the baby’s needs, protein concentrations of breast milk from mothers who deliver preterm is substantially higher than those of mothers who deliver in term. This can be interpreted as evidence of the intimate relationship between mother and child. Nevertheless, it has to be noted that at this point the higher protein values are still not sufficient to provide full premature nutrition (Agostoni et al, 2010).
There is substantial investment in the study of bioactive substances prevalent in mothers’ milk. These substances are defined as compounds that “affect biological processes or substrates and hence have an impact on body function or condition and ultimately health” (Schrezenmeir et al, 2000). A brief list of such factors was summarised by Ballard and Morrow (2013), which, among others, comprises epidermal growth factors important for intestinal growth and repair, neuronal growth factors promoting growth and development of the enteral nervous system, insulin-like growth factors, vascular endothelial growth factors, erythropoietin, calcitonin, somatostatin, adiponectin and many others.
Human breast milk contains different types of cells, which include probiotic bacteria, breast derived cells (lactocytes, myoepithelial, progenitor or stem cells) and blood-derived cells (immunological or hematopoietic cells). These distinct cell types are involved in complex pathways which ultimately support babies’ natural development (Witkowska-Zimny and Kaminska-El-Hassan, 2017).
A major difference between human and cow’s milk is the presence of a large number of potentially beneficial oligosaccharides, the human milk oligosaccharides (HMOs). These oligosaccharides are prebiotics that promote the growth of beneficial bacteria. Some of them can inhibit the binding of pathogens to the intestinal surface.
It is obvious that these (and other) bioactive compounds represent another of the unique properties of breast milk and are able to manage nourishment and protection at the same time.back
Gastrointestinal infections – Breastfeeding decreases the risk of these infections by 64%. This effect is observed even two months after breastfeeding cessation (Stanley et al, 2007).
Otitis media (middle ear infections) – Three or more months of exclusive breastfeeding decreases the risk of middle ear infection by 50%. Shorter durations of exclusive breastfeeding decrease the risk by 23% (Van Rossum et al, 2006).
Severe respiratory infections – Exclusive breastfeeding for at least four months decreases the risk of hospitalisation due to severe respiratory infections by 72% (Agostoni et al, 2009).
Type-II diabetes – Breastfeeding provides a certain degree of long-term protection against the development of type-II diabetes; with lower blood glucose and serum insulin concentrations in infancy, and marginally lower insulin concentrations in later life (Owen et al, 2006).
Lipid metabolism – Breastfeeding leads to lower blood cholesterol concentrations in later life (Owen et al, 2008).
Breastfeeding increases the production of oxytocin, a hormone which supports the postpartum involution of the uterus. This reduces the duration in which the uterus contracts to its former size. Such rapid involution of the uterus also decreases birth related blood losses (Negishi et al, 1999). In addition, oxytocin seems to be a hormone promoting mother-child bonding, as it has long-term anti-depressive properties and promotes contact between the mother and her baby (Galbally et al, 2011).
Next to this, breastfeeding women clearly experience several other future health benefits. For example, the total duration of breastfeeding negatively correlates with the incidence of ovarian cancer, meaning that the longer the mother breastfeeds, the lower is her risk of suffering ovarian cancer. Similarly, the study of Stuebe et al. (2009) shows that in a cohort of premenopausal women with a family history of breast cancer, the characteristic of having ever breastfed at some point in life reduces the incidence of breast cancer, too.
Breastfeeding also seems to decrease the risk of metabolic syndrome – a vicious and widespread complex of various diseases including cardiovascular disease. Women who have breastfed during their lives have a 10-50% lower risk of arthrosis, hypertension, hypercholesterolemia, cardiovascular disease and type-II diabetes (Stuebe, 2009).
This is only a partial overview of the advantages that breastfeeding can have for breastfeeding women – either directly or indirectly. It is a final example of how breast milk, together with breastfeeding, contributes not only the health of the child but also of the mother.back