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CHAPTER 1
Milk Moves
When I explained to our neighbor that I needed to borrow their cooler because I was taking a road trip to Jacksonville to pick up a stash of frozen breast milk, Allie's reaction was one of wide-eyed surprise and curiosity: "What?! You can do that?" As a mother of three, she had a lot of questions: "How did you find it? How does it work? Do you have to match each other, you know, by race or something? Or age? Is she a friend? Do you pay her?" Since many others asked these same questions, this chapter describes the mechanics of pumping and storage, as well as how the sharing system works.
Milk
Human milk is, from an evolutionary perspective, a biological norm, a time-tested standard of care providing babies with well-documented benefits such as decreased risk of infection and protection against allergies, asthma, arthritis, diabetes, obesity, cardiovascular disease, and various cancers (Mead 2008; Van Esterik 2011). Breast milk also contains a range of immunoprotective components, including secretory Immunoglobulin A (IgA), lactoferrin, lysozyme, bifidus factor, oligosaccharides, milk lipids, and milk leukocytes (Wagner, Anderson, and Pittard 1996).
Mothers' milk is not unique to humans, but the synthesis of milk in mammary glands, which are a kind of modified sweat gland, is the defining characteristic of mammals, so understanding its role during critical periods of development in infancy makes milk an important topic of research (Miller et al. 2013). Almost all mammals deliver milk to the young through a teat, or nipple (the two exceptions are the spiny anteater and the platypus, whose babies lick milk off of their mothers' bodies). Below the teat, milk ducts branch out into alveoli, which siphon protein, sugar, and fat from the blood supply for milk production, with full-scale production starting between forty-eight and ninety-six hours after birth, as prolactin levels rise. It is not, as you might have imagined by watching a baby nurse, sucking alone that releases the milk. Nor does it just seep out once it is produced; secretion requires chemical and often physical stimulation. When a mother's milk "lets down," oxytocin and prolactin generate a milk-ejection reflex during which time the alveoli contract and the milk is squeezed out (the nursing baby also stimulates the mother's body to release the hormones that start the let-down).
All milk is not the same — each mother's milk will reflect the conditions of her body — and it changes over time. Milk can contain alcohol, caffeine, or pharmaceutical products that a mother has ingested. It will contain antibodies manufactured by the mother's body in response to her environment. Milk secreted for a new infant — the golden-colored, high-antibody and high-immunoglobulin colostrum — is different from that produced for an older baby. The constitution of milk even changes during a single feeding: foremilk, milk released at the beginning of the feeding, contains less fat than the hindmilk, secreted later in the feeding. As explained by the La Leche League website, milk-making cells
produce only one type of milk, but the fat content of the milk that is removed varies according to how long the milk has been collecting in the ducts and how much of the breast is drained. ... As milk is made, the fat sticks to the sides of the milk-making cells while the watery portion of the milk moves down the ducts toward the nipple, where it mixes with any milk left there from the last feeding. The longer the amount of time between feedings, the more diluted that leftover milk becomes. This "watery" milk has a higher lactose content and less fat than the milk stored in the milk-making cells higher up in the breast. As baby begins nursing, the first thing he receives is this lower-fat foremilk, which quenches his thirst. Baby's nursing triggers the mother's milk ejection reflex, which squeezes milk and the sticking fat cells from the milk-making cells into the ducts. This higher-fat hindmilk mixes with the high-lactose foremilk and baby receives the perfect food, with fat calories for growth and lactose for energy and brain development. (La Leche League 2015)
As the baby nurses, or as the mother pumps, the foremilk slowly changes into hindmilk; there is no discrete point of changeover. Babies need both. And some of our donors labeled pumped milk as "foremilk" or "hindmilk" before freezing it so that the two could be combined at our baby's feeding.
All milk cannot go anywhere, any time. The fact that it spoils, that it has a shelf life (even when frozen solid), that it can be bitter or sweet, that not all babies will take all milk, that making milk requires time and energy, that its constitution changes as the baby develops, and that not everyone can produce it, all contribute to determining to whom milk goes and how. Milk comes in a range of colors (white, blue, yellow, and orange) and textures (viscous or thin). Milk with an excess of lipase (an enzyme in breast milk that helps to break down fat) can smell "off" and taste bitter or soapy (and some babies will not drink it). High-lipase milk is perfectly nutritious but unacceptable to some donees. Others may not accept milk from women taking certain medications. I once rejected milk from a donor who was taking Zoloft even though I learned that doctors identified sertraline as one of the preferred drugs for new mothers because it shows up in breast milk in smaller quantities than other selective serotonin reuptake inhibitors (SSRIS) (Berle and Spigset 2011; Weissman et al. 2004). These qualities influence who gets what milk, how much they can have, and what they do with it.
Looking Around
When I first started searching for studies related to sharing, I discovered a small library of popular trade books, most published since 2005, dealing with everything from work and breastfeeding balance in milk production to the sexual body (Colburn-Smith and Serrette 2007; Tamaro 2005; West and Marasco 2008). I also found a few scholarly texts exploring milk contamination (Boswell-Penc 2006) and constructions of nursing in "appropriate" motherhood (Barston 2012; Wolf 2013). Overtly anthropological work has examined breastfeeding historically (Fildes 1987; Whitaker 2000); as it relates to sexuality and mothering (Mabilia 2005; Zeitlyn and Rowshan 1997); from a biological perspective, especially as compared to formula (Draper 1996; Ebrahim 1980; Ryan 1988); as related to fertility (Jelliffe 1976; Finka et al. 1992); in the context of emerging labor and consumer markets (Gottschang 2007); with regard to kinship (Dettwyler 1998; El Guindi 2011, 2012); vis-à-vis mothering (Barlow 2010; Barlow and Chapin 2010); and in Hiv-positive contexts (Kroeker and Beckwith 2011; Van Hollen 2011).
More germane to my project was research on milk purchased online (Geraghty et al. 2013; Keim et al. 2013; Keim et al. 2015; Stevens and Keim 2015; Stuebe, Gribble, and Palmquist 2014) and some excellent anthropological work based on an analysis of sharing as presented in newspapers as risky and irresponsible (Reyes-Foster, Carter, and Rogers 2015) and from surveys and interviews with donors and donees (Carroll 2015b; Palmquist and Doehler 2014, 2016; Reyes-Foster, Carter, and Hinojosa 2015). What I did not find were in-depth ethnographic studies.
There is, however, plenty of work on the related practice of allo-mothering, which is carrying, providing food, or guarding another mother's offspring from predators, particularly among primates such as vervets, squirrel monkeys, and macaques. The practice of women providing milk for other mothers' babies, or allo-nursing (what we would call "wet-nursing" in a human context), has been observed in many mammals, not just humans. Perhaps there is some kind of adaptive advantage at play, but further research is needed to adequately understand the functions, costs, and benefits for both babies and adults. The act of nursing, for example, may confer advantages (such as fostering a mother-baby emotional connection) while receiving milk without nursing (through the help of technology such as bottles) and may confer others (e.g., nutritional benefits). But even when we do identify the functions, costs, and benefits of milk sharing in primate populations at large, they may or may not all apply in the same way to humans.
A panel at the 2010 American Anthropology Association (AAA) annual meeting focused on a related question. The panel, entitled "Human Consumption of 'Afterbirth' (Maternal Placentophagy): A Natural and Beneficial Practice?," explored the eating of placenta among humans, which is conspicuously absent from the cross-cultural record but ubiquitous among nearly all other terrestrial mammals (save camels). In the United States, where this practice is on the rise, it is sometimes legitimated by referring to it as an "ancient Chinese custom," which reflects a cultural stereotype of Chinese medicine as bizarre yet effective, rather than being based on anything verifiable. Pierre Leinard (2010) reported in this panel that his research in the Human Relations Area Files turned up no evidence showing human placentophagy as a customary practice in any known contemporary or historic cultures.
Other AAA panelists raised questions about placentophagy's absence (or extreme rarity) in prehistoric and historic populations and contemporary human cultures against a small but visible trend in the United States (Benyshek 2010). In her paper on placentophagy and the U.S. home birth movement Melissa Cheyney (2010) has argued that "rituals of the early postpartum period at home including placental examination, celebration, disposal and consumption are intentionally constructed by midwives to communicate messages to mothers about the sufficiency of the birthing body, as well as the sacredness or miraculous quality of their home deliveries." Apparently among home-birth proponents the practice has perceived, if not real, benefits that range from replenishing iron and enhancing lactation to beating back the "baby blues." Cheyney even provides pictures of lasagna and other dishes prepared with placental materials. In fact some breast milk sharing participants I worked with were also involved in placentophagy: one donor is a regional "goto" source for drying the placenta and for making placenta art, and another had her placenta encapsulated for future consumption. Interestingly Sharon Young and Daniel Benyshek (2010) have shown that the hormonal and nutritional content of the human placenta, particularly in dehydrated and encapsulated forms, has not been established.
As with placentophagy, claims about breast milk need further investigation. Because a mother's milk contains antibodies, drinking milk made by many different women could, theoretically, introduce a larger swath of antibodies to the baby. This was an idea I heard repeated by many donors and donees. Even friends who had heard about milk sharing suggested that enhanced antibody diversity was a possible benefit of sharing. A review of current research suggests that milk not only serves immunological functions but also contains factors with a variety of biological roles: milk contains hormones, growth factors, enzymes, lactoferrin, lysozyme, oligosaccharides, nucleotides, antioxidants, and other cellular components that protect against infection, exert an immunomodulant effect, and support beneficial intestinal bacterial flora (Giuliani et al. 2014).
Notable constituents of mature human milk include:
WATER
FAT
Myristic acid
Palmitic acid
Linoleic acid
Alpha-linolenic acid
Arachidonic acid
Docosahexaenoic acid
PROTEIN
Whey protein
Casein protein
HORMONES
Leptin
Ghrelin
Adiponectin
Insulin
Insulinlike growth factor-1 (IGF-I)
Insulinlike growth factor-2 (IGF-2)
Cortisol
IMMUNE FACTORS
Secretory IgA (slgA)
Lactoferrin
Lysozyme
Transforming growth factor beta (TGFß)
Interleukin 1 (IL-1)
Interleukin 6 (IL-6)
Interleukin 10 (IL-10)
Tumor necrosis factor alpha (TNF-α)
CARBOHYDRATES
Lactose
Oligosaccharides
ASH
Vitamin A
Vitamin D
Calcium
Phosphorus
Iron
Zinc
Copper (Miller et al. 2013, 2)
Policy
Today powerful institutions promote breastfeeding or suggest that women offer a combination of breastfeeding and feeding babies mothers' milk. Citing documented long-term and short-term neurodevelopmental advantages, the American Academy of Pediatrics (AAP) began in 2005 to advance breastfeeding and human milk as normative standards for infant feeding and nutrition and recommended exclusive breastfeeding for six months, followed by continued breastfeeding as complementary foods are introduced, with the continuation of breastfeeding for one year or longer as mutually desired by mother and infant. The AAP recognizes contraindications for breastfeeding, such as when the mother has an active, untreated case of tuberculosis or is actively using drugs such as phencyclidine (commonly known as PCP), cannabis, or cocaine.
A 2011 AAP report showed that almost 75 percent of all American women initiate breastfeeding, but this figure obscures some significant demographic information. For example, the rate for breastfeeding in Hispanic populations is about 80 percent, while only about 58 percent of African American mothers initiate breastfeeding. Among mothers participating in the federal Women, Infants, and Children supplemental nutrition program, initiating breastfeeding rates were 67.5 percent overall, but for those with a higher income the rate was 84.6 percent. For low-income non-Hispanic African American mothers the rate was only 37 percent. Older mothers were more likely to breastfeed. The lowest rates of initiation were among non-Hispanic African American mothers younger than twenty, for whom the breastfeeding initiation rate was only 30 percent. The highest rates for exclusive breastfeeding are among urban, white, well-educated women with higher incomes.
If we were to look six months out from the initiation point, the "any breastfeeding" rate in 2011 was 43 percent (with Hispanic or Latinas at 46 percent and non-Hispanic African Americans at 27 percent). Only 13 percent of the mothers met the recommendation to breastfeed exclusively for six months. So as a national population Americans are a long way from the AAP goal, significant internal demographic differences notwithstanding. But why? For one thing, disparities in breastfeeding rates are associated with variations in hospital routines, including when and how formula is presented to new mothers. Other factors implicated in disparities include the media, which often cite difficulties with breastfeeding rather than positive stories, different policies on work and parental leave, social and cultural norms, and advice from family and friends (U.S. Surgeon General 2011). I suspect that there is much more to it, and while this is not a study of breastfeeding per se, demographic differences identified by these reports were strongly reflected in my milk-sharing community, which comprises largely white, educated, and middle-class women who are well aware of the AAP policy.
The policy echoes Breastfeeding and Maternal and Infant Health Outcomes in Developed Countries, a report prepared by the Evidence-Based Practice Centers of the Agency for Healthcare Research and Quality of the U.S. Department of Health and Human Services (Ip et al. 2007). The AAP identifies this report as the most comprehensive analysis of scientific literature comparing breastfeeding to formula. It shows that the risk of hospitalization for lower respiratory tract infections is reduced by 72 percent in the first year for infants breastfed exclusively for more than four months and that any breastfeeding is associated with a 64 percent reduction of nonspecific gastrointestinal tract infections (an effect that lasts for two months after cessation of breastfeeding). Exclusive breastfeeding for three to four months helps reduce the incidence of clinical asthma, atopic dermatitis, and eczema by 27 percent in low-risk populations and up to 42 percent in infants with a family history of these conditions. Finally, there is a reduction of 52 percent in the risk of developing celiac disease in infants breastfed at the time of gluten exposure, a 31 percent reduction in the risk of childhood inflammatory bowel disease, significantly lower rates of obesity, up to a 30 percent reduction in the incidence of type 1 diabetes mellitus in infants exclusively breastfed for at least three months, and a reduction in leukemia that is correlated with the duration of breastfeeding (Eidelman and Schanler 2012).
The case for providing human milk to preterm infants is extremely compelling, according to this study, with regard to preventing necrotizing enterocolitis and promoting growth and neurodevelopment. Breastfeeding also affects maternal health: for example, breastfeeding is associated with decreased postpartum blood loss and more rapid involution of the uterus, while breastfeeding (cumulatively) for twelve to twenty-three months is associated with significant reduction in rates of hypertension, hyperlipidemia, cardiovascular disease, and diabetes. Breastfeeding is also thought to reduce the risk of both breast and ovarian cancers.
(Continues…)
Excerpted from "White Gold"
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