The World Health Organisation recommends exclusive breastfeeding for 6 months and then weaning onto solid foods. Discuss the advantages and disadvantages of this recommendation from the perspective of child development.

Introduction

   Exclusive breastfeeding (EBF) for six months is defined by the World Health Organisation (WHO) as having received no liquids, solids or even water for the first six months of life (Who.int. 2019). This is a very topical issue as there are many disagreements with regards to the optimum duration of time that a child should be EBF for, some suggest four months (Choi et al. 2018) and others suggest 6 (Dewey et al. 2001). This topic also has potential long-term implications on a child’s development and health and therefore it is very important.

   I will discuss 3 of the 5 key areas for a child’s development; Motor, Cognitive and Social & Physical (Shulman and Capone 2010) whilst also referencing to the availability of complimentary foods for children. This essay will argue that the advantages of EBF for 6 months outweigh its disadvantages.

Motor Development

Advantages

   EBF for the first 6 months has been linked with an improvement in infant motor development (Dewey et al. 2001). Two randomised control trials (RCT) were carried out in Honduras that give evidence to support this. A cohort of infants were EBF for the first 4 months and then randomly assigned to continue to be EBF to 6 months or to receive solid foods (SF) as well as breast milk. In both trials the groups that were EBF were seen to be crawling sooner than the groups on SF and in the first study the infants that were EBF were also more likely to be walking by 12 months.

   Both studies only contained first time mothers that were willing to EBF for 6 months. Twins and infants who had severe medical conditions were excluded from the study. This was done because having a medical condition could affect the child’s growth and therefore motor development. With twins, it is well known that it is a lot more difficult for the mother to sustain breastfeeding for them both (Hattori et al. 1999). This could result in both of the twins not receiving the same amount of feeding time as a single child, in turn giving the twins a different food intake to the other children in the study. Both of these factors could have become confounders meaning that they would be responsible for the seen change in motor development, not the EBF or breastfeeding with SF. Therefore, by minimising confounders the inclusion criteria strengthens the findings of this RCT.

   The first study contained only mothers of low-income backgrounds (<$150/month) whereas the second study did not have any limits with regards to the socio-economic backgrounds of the mothers but specified that the infants had to have had a small gestational weight. The second study does not agree with the first study with being more likely to walk at 12 months and this could be explained by the fact that the second study specifically includes infants who had a low gestational weight. Infants with lower gestational weight have been shown to have worse motor ability after 12 months (Moreira et al. 2014). This effect could be more profound than the effect of EBF, resulting in the disparity in results at 12 months.

   Maternal milk has always been known as a very rich source of fatty acids and other compounds that are essential for brain development (Uauy and Dangour 2006). Docosahexaenoic acid and arachidonic acid have been linked with improvements in eyesight and motor development in infants (Lundqvist-Persson et al. 2010). They are present in maternal milk, however, they are not present in formula or cow milk (Lundqvist-Persson et al. 2010). This could also explain the seen motor development benefit in this study.

   The study was an RCT and they are widely accepted as the gold standard for observing whether a specific intervention has a cause-effect relationship (Sibbald and Roland 1998). There is no form of bias or any other explanation of the results apart from being due to the intervention. The random allocation of infants to each group, the equal treatment of each group and the elimination of all possible confounders achieves this (Sibbald and Roland 1998). This is why one could say with confidence that this study proves that it is advantageous in terms of child motor development to EBF for the first 6 months before weaning onto solid foods.

Disadvantages

    EBF for 6 months has been seen to have a negative impact on certain infant’s gross motor development at 6 months (Torsvik et al. 2015). On the contrary to the RCTs carried out in Honduras a more recent part cohort study part randomised intervention trial (RIT) highlighted that 6 months is too long to be EBF infants who have a lower gestational weight (GW). This is due to their inability to receive the adequate amount of vitamin B12 (cobalamin) from breast milk alone.

   Cobalamin is vitamin B12 and is found in lower levels in breast milk (Greibe et al. 2013). It is very important for a rapidly developing nervous system and that is why its levels in infants have motor development ramifications (Torsvik et al. 2013). 

   97 healthy infants with a body weight (BW) of between 2000g and 3000g were selected to be a part of the study. At 6 weeks, 4 months and 6 months they were invited back; the infant’s growth was measured, the infant’s and the mother’s blood was taken and a questionnaire regarding the infant and the mother’s nutrition was also taken. At 6 months, 80 infants remained and their blood was tested for its cobalamin levels. A negative linear association was seen between the amount of times that the children were breastfed and the amount of cobalamin they had in their blood. The p values show the association in the results at 6 months were <0.001. This means that if EBF had no affect on cobalamin levels then you would see the observed difference in less than 0.1% of studies due to study error or chance (Perneger and Combescure 2017). As the p value is less than 0.05 it can be said that we reject the null hypothesis, which in this case states that there is no association between EBF and cobalamin levels (Perneger and Combescure 2017). The results can therefore be thought to be statistically significant and they identify the strong association between EBF for 6 months and cobalamin levels in infants with lower GW.

   The study became a RIT after the 6 months to randomly supplement some of the children who had a cobalamin deficiency with cobalamin and the others with a placebo. One month later a significant improvement was seen in the motor function of infants given the cobalamin intervention, highlighting that the children should have been receiving cobalamin sooner.

   The examiners assessed the gross motor function by using the Alberta Infants Motor Scale (AIMS) that is highly regarded as one of the most reliable tests for measuring gross motor development (Darrah et al. 1998).

   The first part of the study has a cohort design, giving us a clear chronological order of the exposures and outcomes (Setia 2016). However, one of the possible limitations with this study, and cohort studies in general, is loss to follow up bias. As we don’t know the outcomes of those who dropped out, we don’t know the true effect that the EBF would have had on those infants, which can in turn bias the results (Sartipy 2017). However, the study stated that the 17 infants that were lost had no significant affect on the outcomes that we saw, maintaining the strength of this study.

   We know that the seen difference after 6 months is due to the cobalamin supplementation as it was done through an RIT, which clearly identifies the same cause-effect relationship as RCTs identify as I discussed with the previous Honduran study.

   Twins were allowed to be included in the study sample. As I mentioned with the RCT, having twins is not preferred as comparing them to only child infants is difficult due to the possible disparity between feeding amounts (Hattori et al. 1999). This is therefore a limitation of the study.  

   Gross motor development during infancy is a good marker for the child’s neurodevelopment as well (Rydz et al. 2005). Therefore one could hypothesise that EBF for 6 months has a detrimental affects on children who have a lower gestational weight with regards to their neurodevelopment also.

   Having reviewed the methods of this study I would say that this does give evidence that it is a disadvantage for children who are born with a lower gestational weight to be EBF for 6 months.

Physical & Social Development

Advantages

   EBF for 6 months has a strong relationship with lowering the risk of a child becoming obese (Uwaezuoke et al. 2017). Obesity is a multifactorial disease with many possible causes (Grundy 1998). EBF has implications that back some of the hypotheses regarding the development of childhood obesity (Grundy 1998). One of these hypotheses is the feeding behaviour hypothesis. Disantis et al found that EBF in early childhood had a positive influence with regards to appetite regulation in later childhood (Disantis et al. 2011). One hundered and nine children aged between 3 and 6 years old were classified to having either been EBF, fed breast milk from a bottle or formula fed from a bottle during infancy. Their appetites were then studied by measuring their food enjoyment, responsiveness and satiety, all factors that are linked with adiposity and obesity (Wardle et al. 2008).

   As a retrospective cohort study, it was associated with a number of possible limitations. One such limitation was selection bias (Simundić 2013). In order to assess the effect that EBF had on obesity, the study selected participants from data held by a local community-breastfeeding centre. This allowed for the possibility that participants were selected based on the outcome the investigators wanted, rather than selecting a random group of participants.

   Another factor was that the reporting of the child’s feeding was done through self-reporting by the mother. This could allow the mother to not be 100% truthful in her answers and could therefore negatively impact the results. However, the reporting was verified by a medical chart review, meaning that the recall of the feeding method was reasonably accurate enough to ensure that the findings were significant.

   In the same vein as this study, another article made a connection between the amount of milk consumed by the infants who were either EBF or bottle-fed (Li et al. 2010). The results showed that infants who were bottle-fed were more likely to finish all of the milk that had been given to them compared to the EBF children.

   This therefore tells us that the EBF infants are able to control their appetite better whilst also not wanting to consume as much food. This difference between EBF and formula fed infants would be expected to reduce the risk of developing obesity in EBF children later in their childhood.

   Children’s physical development is affected due to obesity as studies have shown that obesity can lead to stunted growth in children (Popkin et al. 1996). This relationship has been seen in developed and non-developed countries and has been recognised as a serious developmental issue (Popkin et al. 1996).

   Obesity doesn’t only affect a child’s physical development but it has deeper psychosocial implications such as causing a child to develop low self-esteem (Strauss 2000). This can have a very negative impact on a child’s social development, leading them to become excluded in social settings (Onoda et al. 2010). This, among other health issues is why obesity is so detrimental to a child’s development.

Cognitive Development

Disadvantages

   EBF for 6 months has detrimental effects on a child’s communicative, social and cognitive development compared to EBF for 4 months, then weaning onto solid foods at 1 year of age (Choi et al. 2018). A longitudinal study conducted in South Korea looked to examine these outcomes at 6 and 12 months. EBF for 6 months has no apparent affect on the outcomes at 6 or 12 months. Whereas EBF for 4 months and then weaning onto solid foods saw benefits in the child’s communicative and social development at 6 months and then better cognitive development also at 12 months.

   255 healthy Korean infants were followed up at 4, 6 and 12 months. Information regarding the breastfeeding habits of the infants were taken at 4 and 6 months and the Korean-Developmental Screening Test for Infants & Children (K-DST) was taken at 6 and 12 months. This was used to measure the developmental milestones of the children. This is a very effective tool to be used for measuring the development of children (Yim et al. 2017).

   The advantage of using a longitudinal study design in this case is that it’s possible to make inferences regarding events and exposures. The study design also removes any form of recall bias, as the subjects can’t be aware of the outcomes, which gives the study strength (Caruana et al. 2015).

   This study is very specific to one ethnicity and doesn’t contain any diverse racial groups. This is a limitation of this study and allows one to say that the observed differences seen could be due to a certain cultural or genetic difference in Korea, which would need more research. For example, the Koreans could have given their 4-month-old babies certain foods to be weaned onto that contained specific vitamins that weren’t accounted for as confounders in this study, which could account for the seen difference in development.

   This is however a very good study of the associations between EBF and children’s cognitive development in the short term in Korea. Allowing us to say that it is disadvantageous for the children to be EBF for 6 months in terms of cognitive development. However, more studies will have to be made using a more diverse cohort in order to see if the results have more global ramifications.

Advantages

   EBF for 6 months has been linked with better cognitive development in children with regards to their intelligence quotients (IQ) in the short and long term (Jedrychowski et al. 2012). The previous Korean study focused on a child’s development in its first year of life, whereas this study gives us the long and short-term effects of EBF on the child, in turn giving us more important information in terms of the true effect of EBF on development. A prospective birth cohort study was undertaken in Krakow to observe what effect did the EBF for 6 months have on the children’s neurodevelopment over a 7-year follow up period. 307 children performed 5 psychometric tests at ages 1, 2, 3, 6 and 7 to assess their cognitive development.

   The results found that as the amount of time the children were EBF for increased from 3 months to 4-6 months to >6months, the children’s IQs also increased with it. These correlations were also seen to the average IQs of each group at age 7, increasing from 2.1 points higher than the average, to 2.6 points to 3.8 points higher. 

   Maternal education during infancy was able to explain 5% of variability in IQ at age 7. However, after adjusting for this confounding factor the association with the duration of EBF was still constant. This adjusting was possible due to the use of the “generalised estimating equation” which has greatly strengthened this study (Ghisletta et al. 2004)

   At 6 and 7 years of age the children underwent the Weschler intelligence test for children (WISC-R). It is common practise to be used in Poland, as it is a reliable and valid tool for measuring general intelligence (Smith et al. 1977). The test is tailored to be representative of the Polish population. This does limit this study to some extent as it did with the previous Korean study making the results less transferable to the global context.

   EBF for 3 months and between 4-6 months didn’t have a fully significant affect on the children’s IQs at 7 years. Although there is a difference, the confidence interval of the results cross 1, therefore it isn’t possible to reject the null hypothesis and the observed results could be down to random chance (Prel et al. 2009). However, there is a significant correlation between the effect of EBF for 6 months and the IQ advantage at 7 years.

   As discussed earlier breast milk contains numerous fatty acids and compounds that are essential for brain development. These omega-3 polyunsaturated fatty acids could explain why EBF for 6 months benefits the cognitive development of infants (Lundqvist-Persson et al. 2010).

   Another explanation could be that children’s long-term psychological development has been linked with maternal attachment status (West et al. 2013). Breastfeeding has been thought to develop the attachment between mother and child through physical and eye contact with each other (Britton et al. 2006).  This could prove why it is an advantage to the child with regards to its psychological and cognitive development to have been EBF for 6 months.

Complimentary Food Availability

   In developing countries such as parts of Africa, India and Papua New Guinea the available complementary foods don’t give the adequate nutrition for infants. Children in these countries have diminished levels of calcium, iron and zinc in their blood (Gibson et al. 1998). These are vital for children’s brain development and growth (Anon 2007). Therefore, for some children it is unsafe for them to stop being EBF before the 6 months as they won’t be able to get all of the vitamins that they would be getting from breast milk (Bates and Prentice 1994).

Conclusion

   In light of the evidence discussing the current WHO recommendation, I have proved my thesis in that the advantages of EBF for 6 months significantly outweigh the disadvantages from the perspective of child development. Not only does breast milk provide all the nutrients a child needs to develop, but the alternative weaning foods are often of a poor nutritional quality, particularly in the developing world. With this being said, a number of studies provide evidence to suggest that the recommendation of EBF should be lowered to 4 months. However, these studies were carried out in specific areas without a diverse cohort, bringing into question their reliability.

   In conclusion, based on the available research, the current WHO recommendation should be applied globally. However, more research should be carried out to explore some of the less well-documented effects of EBF, such as the possible physical development sides of the argument.

REFERENCES:

• Anon, 2007. Iron needs of babies and children. Paediatrics & child health, 12(4), pp.333–6.
• Bates & Prentice, 1994. Breast milk as a source of vitamins, essential minerals and trace elements. Pharmacology and Therapeutics, 62(1), pp.193–220.
• Britton, John R, Britton, Helen L & Gronwaldt, Virginia, 2006. Breastfeeding, sensitivity, and attachment. Pediatrics, 118(5), pp.e1436–43.
• Caruana, E.J. et al., 2015. Longitudinal studies. Journal of thoracic disease, 7(11), pp.E537–40.
• Choi, H., Kang, S. and Chung, M. (2018). The relationship between exclusive breastfeeding and infant development: A 6- and 12-month follow-up study. Early Human Development, 127, pp.42-47.
• Choi, H., Kang, S. and Chung, M. (2018). The relationship between exclusive breastfeeding and infant development: A 6- and 12-month follow-up study. Early Human Development, 127, pp.42-47.
• Darrah, J., Piper, M. & Watt, M.J., 1998. Assessment of gross motor skills of at‐risk infants: predictive validity of the Alberta Infant Motor Scale. Developmental Medicine & Child Neurology, 40(7), pp.485–491.
• Dewey, K., Cohen, R., Brown, K. and Rivera, L. (2001). Effects of Exclusive Breastfeeding for Four versus Six Months on Maternal Nutritional Status and Infant Motor Development: Results of Two Randomized Trials in Honduras. The Journal of Nutrition, 131(2), pp.262-267.
• Disantis, K.I. et al., 2011. Do infants fed directly from the breast have improved appetite regulation and slower growth during early childhood compared with infants fed from a bottle? The International Journal of Behavioral Nutrition and Physical Activity, 8(1), p.89.
• Ghisletta, Paolo & Spini, Dario, 2004. An Introduction to Generalized Estimating Equations and an Application to Assess Selectivity Effects in a Longitudinal Study on Very Old Individuals. Journal of Educational and Behavioral Statistics, 29(4), pp.421–437.
• Greibe, E. et al., 2013. Cobalamin and haptocorrin in human milk and cobalamin-related variables in mother and child: a 9-mo longitudinal study. The American journal of clinical nutrition, 98(2), pp.389–95.
• Grundy, S.M.M., 1998. Multifactorial causation of obesity: Implications for prevention. American Journal of Clinical Nutrition, 67(3), p.563S.
• Hattori, Ritsuko & Hattori, Haruo, 1999. Breastfeeding Twins: Guidelines for Success. Birth, 26(1), pp.37–42.
• Jedrychowski et al., 2012. Effect of exclusive breastfeeding on the development of children’s cognitive function in the Krakow prospective birth cohort study. European Journal of Pediatrics, 171(1), pp.151–158.
• Li, R., Fein, S.B. & Grummer-Strawn, L.M., 2010. Do infants fed from bottles lack self-regulation of milk intake compared with directly breastfed infants? Pediatrics, 125(6), pp.e1386–93.
• Lundqvist-Persson et al., 2010. Early behaviour and development in breast-fed premature infants are influenced by omega-6 and omega-3 fatty acid status. Early Human Development, 86(7), pp.407–412.
• Moreira, Magalhães & Alves, 2014. Effect of preterm birth on motor development, behavior, and school performance of school‐age children: a systematic review. Jornal de Pediatria, 90(2), pp.119–134.
• Onoda, K. et al., 2010. Does low self-esteem enhance social pain? The relationship between trait self-esteem and anterior cingulate cortex activation induced by ostracism. Social Cognitive and Affective Neuroscience, 5(4), pp.385–391.
• Perneger & Combescure, 2017. The distribution of P-values in medical research articles suggested selective reporting associated with statistical significance. Journal of Clinical Epidemiology, 87(C), pp.70–77.
• Popkin, B.M., Richards, M.K. & Montiero, C.A., 1996. Stunting is associated with overweight in children of four nations that are undergoing the nutrition transition. The Journal of nutrition, 126(12), pp.3009–16.
• Prel, J., Hommel, G., Röhrig, B. and Blettner, M. (2009). Confidence Interval or P-Value? Part 4 of a Series on Evaluation of Scientific Publications. Deutsches Aerzteblatt Online, 106(19), pp.335–339.
• Rs Gibson, El Ferguson & J Lehrfeld, 1998. Complementary foods for infant feeding in developing countries: their nutrient adequacy and improvement. European Journal of Clinical Nutrition, 52(10), pp.764–770.
• Rydz, D. et al., 2005. Developmental screening. Journal of child neurology, 20(1), pp.4–21.
• Sartipy, U., 2017. Loss to Follow-Up? The Annals of Thoracic Surgery, 103(3), p.1037.
• Setia, M.S., 2016. Methodology Series Module 1: Cohort Studies. Indian journal of dermatology, 61(1), pp.21–5.
• Shulman, B. and Capone, N. (2010). Language Development. 1st ed. Jones and Bartlett Publishers, pp.35-45.
• Sibbald, B. & Roland, M., 1998. Understanding controlled trials – Why are randomised controlled trials important? British Medical Journal, 316(7126), p.201.
• Simundić, A.-M., 2013. Bias in research. Biochemia medica, 23(1), pp.12–5.
• Smith, A.L., Hays, J.R. & Solway, K.S., 1977. Comparison of the WISC-R and Culture Fair Intelligence Test in a Juvenile Delinquent Population. The Journal of Psychology, 97(2), pp.179–182.
• Strauss, R.S., 2000. Childhood obesity and self-esteem. Pediatrics, 105(1), p.e15.
• Torsvik, I. et al., 2013. Cobalamin supplementation improves motor development and regurgitations in infants: results from a randomized intervention study. The American journal of clinical nutrition, 98(5), pp.1233–40.
• Torsvik, I.K. et al., 2015. Motor development related to duration of exclusive breastfeeding, B vitamin status and B12 supplementation in infants with a birth weight between 2000-3000 g, results from a randomized intervention trial. BMC pediatrics, 15(218), p.218.
• Uauy, R. & Dangour, A.D., 2006. Nutrition in Brain Development and Aging: Role of Essential Fatty Acids. Nutrition Reviews, 64, pp.S24–S33.
• Uwaezuoke, S.N., Eneh, C.I. & Ndu, I.K., 2017. Relationship Between Exclusive Breastfeeding and Lower Risk of Childhood Obesity: A Narrative Review of Published Evidence. Clinical Medicine Insights: Pediatrics, 11(11), p.1179556517690196.
• Wardle, J. et al., 2008. Obesity associated genetic variation in FTO is associated with diminished satiety. The Journal of clinical endocrinology and metabolism, 93(9), pp.3640–3.

• West, Katara K., Mathews, Brittany L. & Kerns, Kathryn A., 2013. Mother-Child Attachment and Cognitive Performance in Middle Childhood: An Examination of Mediating Mechanisms. Early Childhood Research Quarterly, 28(2), pp.259–270.
• Who.int. (2019). WHO | The World Health Organization’s infant feeding recommendation. [online] Available at: https://www.who.int/nutrition/topics/infantfeeding_recommendation/en/.
• Yim, C.-H., Kim, G.-H. & Eun, B.-L., 2017. Usefulness of the Korean Developmental Screening Test for infants and children for the evaluation of developmental delay in Korean infants and children: a single-center study. Korean Journal of Pediatrics, 60(10), pp.312–319.