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The secret bond between mother and child: The power of breast milk nutrients

Having a baby is considered a unique and incomparable experience in the life of any woman, and breastfeeding is often described as one of the moments that most contributes to creating that special bond between a mother and child.

Indeed, the act of breastfeeding allows a mother and baby to be at the perfect distance to look into each other’s eyes, as well as allowing skin to skin contact, which elicits the primordial instincts of protection and belonging.

We are now approaching World Breastfeeding Week 2019 (1–7 August) and so, there is no better time than now to open a discussion about breastfeeding and its implications in mental health.


Breast milk is commonly considered as the gold standard for feeding newborns, thanks to its complete composition, which includes all of the nutrients and physiological hormones a baby needs for optimal growth, as well as immunological components, such as a wide array of different antibodies, able to protect the baby in the first few months of life.

The UNICEF and the World Health Organisation recommend that babies should be exclusively breastfed during their first 6 months. After this period, food should be gradually introduced, but should be done alongside breastfeeding until the baby reaches at least 2 years of age. The duration and exclusiveness of breastfeeding have indeed been proposed to contribute to the development of children’s brain and improve their IQ up until adulthood, although these findings have not been replicated in some occasions, keeping an open debate on this matter.



Breastfeeding and mental health


In some cases, the transition into the new role of being a mother might not be as smooth or as natural as society typically makes it out to be. This is especially the case for women suffering from mental health problems across the “perinatal” period, meaning either during pregnancy (antenatal), or in the first year after giving birth (postnatal or postpartum).

Depression affects around 10–20% of women in the perinatal period, and it is common for new mothers, who are already suffering with this strong emotional distress, to feel even more pressured and inadequate when they don’t feel the telltale call to breastfeed, and they struggle to accomplish what is supposedly a ‘natural, enjoyable and effortless experience’, in the eye of society.

Interestingly, women at risk of, or already suffering from, depressive symptoms, are commonly encouraged to breastfeed by their clinicians, because some of the hormones which increase during lactation, especially oxytocin and prolactin, can reduce stress in the maternal body.

Therefore, theoretically, breastfeeding might act as a form of protection against the development of postpartum depression, although the link between breastfeeding and depression is still not completely understood.

A multitude of biological and psychological factors are involved and need to be taken in consideration, and a chicken or the egg-like conundrum still exists, when trying to explain if early cessation of breastfeeding increases the risk of postpartum depression or if the onset of depression might be the cause of reduced breastfeeding.


However, as we discussed in a previous blog on Inspire the Mind, babies born from depressed mothers have a higher chance of developing mental health problems as they grow.

And, as for the potential biological mechanisms underlying this correlation, genetic and hormonal alterations are likely to play a major role, even from pregnancy, when the baby is still developing in the mother’s womb.

But what about after the baby is born? Could breast milk be a vehicle for the transmission of a biological signal from a depressed mother to her baby?



Breast milk composition and the effects of maternal mental health


Our recent paper, published in Brain, Behavior and Immunity, presents the resultsof a vast body of literature to explore how the molecular composition of breast milk might represent a bridge between maternal mental health and child brain development.

In our review, we identify a number of studies which show that maternal mental health problems can affect breast milk in a potentially negative way. More specifically, that altered patterns of some nutritional and immune components are present in the milk of mothers suffering from mental health problems (depression, anxiety or stress) and also are associated with difficulties in normal child development. However, this is not to downplay the many positive effects of breastfeeding.


For example, women suffering from depression during pregnancy have lower levels of omega-3 fatty acids in the breast milk. Omega-3 fatty acids are “good fats”, usually obtained through a diet rich in fish and nuts, and have long been recognized for their fundamental role in improving brain development and functioning.

Indeed, other studies included in our paper demonstrate that higher levels of omega-3 fatty acids, received through breast milk, have a beneficial role in improving intelligence and cognitive abilities throughout childhood.

Another interesting point that came out in our review is the important role of the secretory Immunoglobulin A (sIgA) in breast milk.


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Immunoglobulin A is an antibody (a proteic complex that attacks disease-carrier germs) which is normally present in breast milk, especially in the first few months after birth, and it is fundamental for the immunological protection of the newborn babies, who still have not completely developed their own immune system at this stage.

In one study, researchers reported that depressed mothers have high milk sIgA levels and have babies with an improved ability to react to outside stimuli, like reaching out for a colorful toy or turning toward a parent’s voice, which is a sign of a better brain development.


The increased levels of this immunological molecule in the milk of depressed mothers might thus represent a form of protective mechanism to defend the baby against any negative environmental changes potentially occurring as a consequence of mothers’ mental health problems.

Interestingly, our review also finds that many other nutritional components, including vitamin B6, which plays a fundamental role for brain functioning, and several hormones, such as cortisol, prolactin and melatonin, which are involved in the stress response, are altered in breast milk of mothers with mental health problems.

Moreover, and, most importantly, such alterations are associated with different emotional and behavioral reactions from children.

For example, babies receiving breast milk with less vitamin B6 cry for longer periods and are more fussy. Babies breastfed with a milk richer in cortisol, a hormone elevated by stress, also show a higher inclination for negative emotions.



The unanswered questions


Although a lot of evidence has demonstrated the exceptional nutritional properties of breast milk, there are still many questions to be answered with regards to its influence on child brain development, including which milk components play a more prominent role for a child’s brain, and which mechanisms are involved in their effect.

Most importantly, little is known on how maternal mental health can affect breast milk composition, and subsequently child growth, and to what extent these alterations might underlie the increased risk of developing mental health problems in children born from depressed mothers. Further research is needed to shed light on these questions.


Moreover, although breast milk represents an invaluable source of nutrients for the child, breastfeeding should not be considered as a mandatory duty for every new mother, especially if it comes at the costs of a worsening mental health. In some cases, adopting an alternative feeding method, or breastfeeding for a shorter period of time, might actually be a valuable option. Sometimes alternative feeding methods might better suit the mother’s personality or situation, and ultimately contribute to the development of a stronger and safer bond with the child. Most importantly, women who are not able to breastfeed their children should not be negatively judged from their partner, family or society. Because of these unaswered questions, future research should continue to investigate the secrets behind breast milk composition and child development, and most importantly, should aim to identify the role that perinatal mental health plays in this intricate mother-milk-child link. Ultimately this will contribute to the discovery of new treatment approaches targeting both the mother and the child.


 

NOTE FROM THE AUTHOR: Many thanks to Alessandra Borsini for her support and collaboration to accomplish the great work that allowed the publication of the paper on which this blog is based.




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