Breast milk is considered to be the most appropriate nutrition for newborn babies and young infants. New data show that breast milk participates in the metabolic and immunological programming for the newborn, partially by facilitating the colonization of the infant’s gut with beneficial bacteria, which are naturally present in the milk. However, not all breast milks are the same. The composition of breast milk depends on various parameters. Maternal diet and lifestyle can influence not only the nutritional and immunological value of breast milk, but also the types of bacterial strains present and their relative abundance.
Scientists believe that breast milk contains hundreds of unique bioactive substances, which protect against infection and inflammation, program immune maturation and promote organ development. For example, lactoferrin, an important protein found in human (and mammalian) breast milk is currently being investigated as a novel antimicrobial agent in a variety of clinical settings, such as prevention of hospital infections in neonatal intensive care units and diarrhea in children. Human milk also contains a unique class of sugars, known as type I oligosaccharides. Despite the fact that the baby does not have the enzymes to break them down, these undigested sugars eventually feed the first beneficial bacteria of the infant’s gut (mainly Bifidobacteria). Breastfeeding provides the young child both superior nutrition and protection. The composition of breast milk depends on many factors; its composition changes constantly throughout the lactation period and is inevitably different between mothers. The overall concentration of protein and immune factors declines naturally during lactation. This trend could indicate that the immune and digestive system of the infant is considered mature enough to continue its development with reduced maternal nutritional input.
On the other hand, maternal diet is a major factor that affects the concentration of many important nutritional molecules in breast milk. There is substantial research evidence showing that presence of essential fatty acids (omega 3) in breast milk depends on the maternal dietary intake. A study published in The Journal of Nutrition, in 2012, investigated the effects of fish oil supplementation or salmon consumption during and after pregnancy. The results show that it is the mother’s dietary patterns, during gestation and lactation that determine the adequate supply of omega 3s to their offspring before and after birth. The contribution of omega 3 fatty acids (mainly DHA and EPA) in health and wellbeing is well established.
Although no research has been done specifically for young infants, it is known that sufficient consumption and adequate levels in the blood of these miraculous molecules in adults have a dramatically positive impact in cases of cardiovascular disease, cancer, cognitive decline and can even protect the DNA from oxidative damage. Breast milk enriched in omega 3s, also contains high levels of important immune factors. A study published in the British Journal of Nutrition, in 2012 confirms that apart from high levels of beneficial fatty acids, the milk from mothers residing in areas with higher fish consumption (coastal and river/lake regions) has higher levels in soluble CD14 (sCD14), transforming growth factor (TGF)-β1 and secretory IgA (sIgA).
Breast milk contains numerous bacterial strains, which colonize the infant’s gut. The bacteriological composition of breast milk seems to be directly related to the mother’s lifestyle, as it is indicated by her weight and Body Mass Index (BMI). An interesting study published in the American Journal of Clinical Nutrition, in 2010 has shown that maternal BMI influences the relative presence of beneficial bacteria in breast milk, which is subsequently reflected in the infant’s gut microbes. The study found that milk from overweight mothers had consistently lower numbers of beneficial bacteria (Bifidobacteria) and higher numbers of potentially pathogenic bacterial strains.
It confirms that during the first 6 months of their life, the gut of infants from overweight mothers (pre-pregnancy BMI bigger than 25) has already been extensively colonized by potential pathogens, such as Staphylococcus, Clostridium, Bacteroides and Akkermansia muciniphila. Several studies have found that breast milk from overweight mothers also has different composition in immunological compounds, such as TGF-β2, sCD14, interleukin – 6. Given the fact that certain gut microbiota and immunological profiles are associated with obesity and metabolic disease, the above data suggest that mother’s weight and lifestyle affect the quality of breast milk and the baby’s gut flora, but it may also increase the child’s risk for obesity.
Breastfeeding is not simply a source of nutrients for the newborn. The mother, through her breast milk quality, programs critical immunological, metabolic and microbiological aspects of the baby’s physiology that will determine greatly his/her health status, even as an adult.
Eleni Roumeliotouleni- Roumeliotou has trained as a geneticist, gaining a Master degree in Human Molecular Genetics by Imperial College London, UK. She left the academic research environment to focus on her true passion, which is evidence-based natural health and alternative medicine. She is currently working as a freelance writer.
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