Incorporating new evidence-based information about putting lactation into practice is a critical component of the role of the IBCLC. As additional information becomes available, it is a challenge to place it in the context of what has already been established both in the field of lactation and in the broader fields of anatomy and physiology.
Our guest blogger Sue Cox, an IBCLC since 1985 and the author/presenter of over 80 papers, addresses the research in hot topics in the IBCLC profession today, including questions about breastmilk composition when shaken, agitated, or left in the breast between long feedings. Watch for part two of this post next Wednesday where she will share her reflections on the research on other commonly asked questions about breastfeeding.
On Listening, Then Reviewing/Pondering What We Read and Hear
In this blog post, I will be commenting on some of the discussions I have read on the Internet and heard in professional conversation lately. I hope these quotes – on which I have based my professional life as an IBCLC – will help guide your thinking.
. . . Continued learning requires that we seek new knowledge and [accept] the challenge that takes place when our own interpretations on ways of doing things are questioned by others. That is the price we must pay if we are to hone our skills, increase our knowledge and strive to keep to the best of our abilities for those women who seek our assistance and depend upon us for guidance.
Kathleen Auerbach, (1987) J.Hum Lact 3(4).
Receptiveness to what we hear is vital, but what we hear needs always to be backed up by physiological/biochemical/ anatomical/endocrinological and/or psychological understandings.
Sue Cox 2014.
Note from the editor: Much recent research has addressed how best to handle expressed human milk, with the goal of maintaining the integrity of the milk components and more evenly distribute the components within the liquid. This has, in turn, generated conversation about ways to more evenly distribute nutrients, especially human milkfat, throughout milk during breastfeeding. Read on for the research that Sue provides to further discussion in each of these areas.
Will agitating a syringe of expressed breastmilk for infusion to premature infants homogenize the milk?
Ultrasound has previously been shown to homogenize cow milk (Ertugay & Sengul, 2004).
Ertugay, FM, Sengul, M (2004) Effect of Ultrasound Treatment on Milk Homogenisation and Particle Size Distribution of Fat. Turk J Vet Anim Sci 303-308.
In the recent study by Garcia-Lara and colleagues (2014) the researchers sought to extend knowledge of the most appropriate routine to decrease fat loss in infused expressed breastmilk for premature infants. The word homogenization occurred in the title: “Type of homogenization and fat loss during continuous infusion of human milk.” Three methods were used to mix the milk in the syringe: baseline agitation, hourly agitation and ultrasound. The first two methods simply reconstituted the milk but did not make every drop the same as in homogenization.
Garcia-Lara et al., (2014) Type of homogenization and fat loss during continuous infusion of human milk. J Hum Lact 0890334414546044, first published on August 13, 2014 as doi:10.1177/0890334414546044.
Could shaking the breast homogenise milk?
Breastmilk in the alveoli is a suspension of fore- or skim- milk with small amounts of fat suspended in it, but most of the fat is bonded to the epithelial lining of the alveoli.
If breastmilk were to be homogenised it would require a “factory setting” in which it would be altered from a suspension to an emulsion where every drop would be the same.
Homogenisation is a process in which the fat droplets are emulsified and the cream does not separate http://www.oxforddictionaries.com/definition/english/homogenize
Even after centrifuging, all of the fat globules do not separate and fat is seen in the skim fraction of the milk (Czank et al, 2009)
Czank, C, Simmer K, and Peter E Hartmann, PE (2009) A method for standardizing the fat content of human milk for use in the neonatal intensive care unit. Int Breastfeed J. 2009; 4: 3.
Could shaking the breast or breast massage increase the fat content earlier in the feed?
Whittlestone (1953) hypothesised that the fat globules adhered to the walls of the alveoli and ducts.
Whittlestone WG (1953) Variations in the fat content of milk throughout the milking process. J Dairy Res 20: 146–153
Foda (2004) found that when samples of expressed milk were taken within 30 minutes before Okatani massage and then the breast was fully hand expressed after massage that there were increased fat levels in the post-massage breastmilk but this only occurred after lactation was well established which in that study was after three months. No reference was made to the effect that the massage may have had on milk ejections occurring which increase fat levels in milk, nor was there mention of degree of fullness or time since the previous feed.
Foda et al., (2004) Composition of milk obtained from unmassaged versus massaged breasts of lactating mothers. J Pediatr Gastroenterol Nutr.;38(5):484-7.
Morton et al (2012) found that when mothers who were expressing for their premature babies used hand expression and breast compression during pumping that their milk exceeded normal fat and energy levels after the first week postpartum.
Sue notes here that the breasts would have been well drained at each expressing and pumping session.
Morton J, et al., (2012) Combining hand techniques with electric pumping increases the caloric content of milk in mothers of preterm infants. J Perinatol. 32(10):791-6
Would altering breastmilk so that the infant received creamier milk earlier in the feed be an advantage to the baby?
Karatas (2011) suggested that the weight patterns in healthy breastfed infants at their second and fifth months is based on the satiety from changes in breastmilk ghrelin, leptin, and fat levels between the foremilk and hindmilk.
Karatas Z et al., (2011) Breastmilk ghrelin, leptin, and fat levels changing foremilk to hindmilk: is that important for self-control of feeding? Eur J Pediatr. 2011 Oct;170(10):1273-80.
Various theories have been suggested about how/why the fat detaches including: the decrease in surface area as the alveoli are being drained of milk during a feeding (Atwood & Hartmann, 1992; Neville, Allen & Watters, 1983; Hytten, 1954); the effect of hormones oxytocin and prolactin and/or alteration in gene expression as the alveoli is drained (Hassiotou et al., 2012; Hall, 1979) .
Atwood CS, Hartmann PE (1992) Collection of fore and hind milk from the sow and the changes in milk composition during suckling. J Dairy Res 59: 287–298.
Neville MC, Allen JC, Watters C (1983) The mechanisms of milk secretion; Neville MC, Neifert MR, New York and London: Plenum Press. 49–102.
Hytten FE (1954) Clinical and chemical studies in human lactation. I. Collection of milk samples. Brit Med J 23: 175–182.
Hassiotou F, Geddes DT, Hartmann PE (2012) Cells in human milk: State of the science. J Hum Lact 29: 171–182.
Hall B (1979) Uniformity of human milk. American Journal of Clinical Nutrition 32: 304–312.
Does milk separate in the breast if there are long gaps between feeds?
The greater portion of the milk is stored in the alveoli until required (Geddes, 2009). High-resolution ultrasound images (Geddes, 2009) show the flow of milk as the ducts dilate in the breast following oxytocin-mediated milk ejection (shown by flecks in the milk in the duct as the milk is ejected as well as in the infant’s oral cavity). When milk removal ceases the residual milk returns to the alveoli.
Geddes D (2009) The use of ultrasound to identify milk ejection in women – tips and pitfalls. Int Breastfeed J. 2009; 4: 5. doi: 10.1186/1746-4358-4-5
Hassioto et al., (2013) found that when milk was expressed before, after and then at 30- minute intervals for three hours after breastfeeds that the highest fat levels were found 30 minutes after the end of milk removal. This supports the utrasound findings of Geddes (2009) that showed how residual fat returns to the alveoli after milk removal.
Hassiotou F, et al., Breastmilk cell and fat contents respond similarly to removal of breastmilk by the infant. PLoS One. 2013; 8(11): e78232. Published online Nov 6, 2013. doi: 10.1371/journal.pone.0078232
In conclusion, the suggestion that homogenization can be achieved by simply shaking or agitating breastmilk in the breast or in another receptacle is an incorrect use of the word homogenize. The use of the word homogenize in the context of human lactation and breastfeeding requires scholarly review.
Watch for Sue’s next guest post, where she presents the research on other key areas of breastfeeding practice today.