Biomilq and the New Science of Artificial Breast Milk

In 2src2src, the company received $3.5 million in funding in a round led by Breakthrough Energy Ventures, an investment firm founded by Bill Gates. Biomilq’s early days were shaped by the pandemic. This came with difficulties—the company’s lab manager recalls trading with neighboring startups for gloves and pipettes during supply-chain shortages—but also unexpected benefits. Strickland

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In 2src2src, the company received $3.5 million in funding in a round led by Breakthrough Energy Ventures, an investment firm founded by Bill Gates. Biomilq’s early days were shaped by the pandemic. This came with difficulties—the company’s lab manager recalls trading with neighboring startups for gloves and pipettes during supply-chain shortages—but also unexpected benefits. Strickland and Egger would hear “Sesame Street” in the background during calls with investors and know that they were talking to working parents. In 2src21, they closed a twenty-one-million-dollar series-A funding round. Then, in 2src22, a national formula shortage brought urgent attention to the matter of how babies get fed. It was an opening for a company like Biomilq to promote an alternative—and the opening arrived in an era of enthusiasm for tech-based solutions to the fundamental problems of human life. If fertility and longevity were subject to biotech intervention, why not infant nutrition, too?

The process of making breast milk in a human body begins during pregnancy, when hormonal changes prompt mammary cells to multiply. After delivery, two of the pregnancy hormones—estrogen and progesterone—drop off, while prolactin remains. This spurs the mammary cells to draw carbohydrates, amino acids, and fatty acids from the mother’s bloodstream, and to convert these raw materials into the macronutrients required to feed a baby. In Biomilq’s case, the mammary cells come from milk and breast-tissue samples provided by donors, and the cells multiply in vitro under the care of a team of scientists tasked with keeping them “happy.” The cells are then moved to a hollow-fibre bioreactor—a large tube filled with hundreds of tiny porous tubes that are covered in a layer of the lab-grown cells. As nutrients flow through the small tubes, the cells secrete milk components into the large tube, where they collect.

“Honey, did we order a hit?”

Cartoon by Mick Stevens

Describing the results as “milk components,” not “milk,” is a crucial distinction. Biomilq has demonstrated that its technology can produce many of the macronutrients found in milk, including proteins, complex carbohydrates, and bioactive lipids, but it cannot yet create them in the same ratios and quantities necessary to approximate breast milk. Other elements of breast milk are beyond the scope of the company’s ambition. A mother’s antibodies, for example, are present in her milk, but they aren’t produced by the mammary cells, and, because Biomilq’s product will come from a sterile lab environment, it won’t offer any kind of beneficial gut bacteria.

Then there’s breast milk’s characteristic variability—the way its chemical composition changes over the course of months, days, even a single feed—and its ability to respond (through the mechanism of infant backwash, some suggest) to the nutritional needs of a particular baby. Whatever Biomilq winds up being, it will have to be uniform, and “that is not breast milk,” Strickland said. But she still believes in the power of what’s produced by the human mammary cell. Bovine milk and human milk may have some of the same proteins, but there are “species-specific differences in how those proteins are processed,” she said. “We believe that these components will be more bioactive, more absorbable, and interact better with the gut of the infant.”

Katherine Richeson, who oversees product development at Biomilq, is a cell biologist who conducted research on cancer therapies, including breast-cancer treatment, prior to coming to the company. She was struck by the dearth of research on mammary cells in relation to lactation. “Reading the literature didn’t take that long,” she told me. Bruce German, a chemist and food-science professor at the University of California, Davis, is a leading researcher on the subject of human milk. His work has shown how even indigestible parts of breast milk help to nourish bacteria that improve infants’ gut health. (German has also provided unpaid advice to Biomilq.) He sees the historic lack of academic interest in lactation as the result of prioritizing the concerns of “middle-aged white men” over those of mothers and infants. “There are more papers on wine than there are on milk,” he said.

Biomilq’s methods and equipment are drawn from the world of biopharmaceutical technology, and using them to create a commercially viable food product will require working on a radically different scale. “It’s a two-pronged challenge,” Strickland said. “We want to make orders of magnitude more stuff than what the technology is designed for today, and we want to sell that stuff orders of magnitude cheaper.” When asked about the company’s target consumer, Strickland said that it would be a “worst-case scenario” for her if Biomilq replicated the inequalities that already plague infant feeding. “I won’t consider it a success until it’s fully accessible,” she told me. Egger took a somewhat more pragmatic stance: the company was aiming to one day be priced “at the top end” of infant formula, and would likely be more expensive than that at the beginning. “While accessibility is first and foremost for us, it’s not going to be accessible to every person in the world immediately,” Egger said. For now, the company is making a pitch to customers who are already sold on the value of breast-feeding but are frustrated by its challenges, and who are willing to pay to get their child the next best thing.

The relative value of the next best thing is an open question. “What we care about is not just the best nutritional start in life—we’re looking for the best start in life,” Laurence Grummer-Strawn, who works at the World Health Organization and specializes in infant and early-childhood nutrition, told me. The “best start” offered by breast-feeding encompasses all the things impossible to incorporate into a cell-cultured product—breast milk’s fine-tuned changeability, the parent-child bonding. Without those, “we’re talking about essentially a better formula,” Grummer-Strawn went on. “But frankly, from a nutritional perspective, infant formula is not that bad.” He saw the focus on minute chemical improvements as part of a broader American tendency to prioritize breast milk, the substance, over breast-feeding, the act.

I was thirty-one weeks pregnant when I visited Biomilq’s headquarters, and by then I’d heard friends’ stories of their own labor-intensive efforts to generate human milk. For people embarking on parenthood in 2src23, breast-feeding is a recommendation right up there with “Read to your child” and “Don’t smoke.” A large number of American parents start out doing so—83.2 per cent of infants born in 2src19 were breast-fed at least briefly, according to the C.D.C. But by six months—the age through which the American Academy of Pediatrics recommends that babies consume only breast milk—24.9 per cent were exclusively breast-fed, and only 55.8 per cent were receiving breast milk at all. “It’s pretty incontrovertible that breast-feeding is optimal nutrition for the baby,” Olena Dobczansky, a nurse and lactation consultant who oversees the breast-feeding program at Manhattan’s Lenox Hill Hospital, told me. It’s just that families leave hospitals like hers and confront a reality that makes the A.A.P. guidelines sound fantastical. “A fourth of American mothers go back to work two weeks after having a baby,” Dobczansky said. At that point postpartum, she noted, “you’re still bleeding.” Paid maternity leave—which, among high-income countries, only the U.S. does not mandate—translates to higher rates of breast-feeding.

Even for parents lucky enough to receive generous paid leave, it takes practice, and often the help of someone with experience, to get a baby properly latched and nursing. The journey from there may involve frightening uncertainty (is the baby getting enough to eat?) and physical discomfort (sore nipples, mastitis), and requires time—breast-feeding is, especially in the beginning, a constant occupation. Pumping necessitates its own choreography. Women I know became fluent in paraphernalia with names ranging from puns (the My Brest Friend nursing pillow) to euphemisms (the Simple Wishes hands-free pumping bra). Some presided over their own frosty vaults: pumping then stockpiling in dedicated freezers, and fretting over power outages during storms. Milk, I was learning, didn’t have to be the result of biotech innovation to seem faintly experimental and very precious.

The story of breast-feeding in America could start with Cotton Mather, who admonished Puritan women to nurse their babies rather than become “one of the careless women, living at ease”—a call to health and hard work which has never quite abated where motherhood is concerned. But who breast-feeds and why has been defined by the same forces that shape life in America more broadly. In the antebellum South, for example, Black women were made to nurse white babies at the expense of their own. Nearly two hundred years later, Black women’s breast-feeding rates lag behind those of other demographic groups, one of many health disparities—along with a stark maternal-mortality rate—that form part of the ongoing legacy of slavery.

“It’s as fraught as abortion,” Jacqueline Wolf, an emeritus historian of medicine at Ohio University and the author of a history of breast-feeding and formula in the U.S., aptly titled “Don’t Kill Your Baby,” told me. “There’s almost nothing that raises more social issues than infant feeding.” Wolf dates the emergence of what became known as “the feeding question” to the eighteen-seventies, when mothers across the country began raising concerns about their milk supply. “The big change that was sparked by urbanization and industrialization was suddenly having to pay attention to a mechanical clock,” she said. Earlier infant-care manuals had advised feeding a baby when he showed signs of hunger. Now medical advice put infants on feeding schedules as rigid as railway timetables. But, as Wolf pointed out, “to build up a milk supply, you need to put the baby to the breast often, especially in the first few months.” The women complaining that they lacked sufficient milk were not, as one theory had it, suffering from the ill effects of too much education during puberty. Rather, they were following advice unwittingly engineered to fail. The contours of the American conversation around breast-feeding were thus established: expert authority counselled one thing, practical reality dictated another, and mothers who found themselves caught in between were often regarded as the source of the problem.

One miracle solution of the late nineteenth century came from a new feature of urban life: milk laboratories, which provided some in the middle class with access to “percentage feeding.” A doctor would study a baby’s stool and arrive at a precise mathematical formula (hence “formula”) for her diet. A milk-laboratory chemist would tweak cow’s milk accordingly. The dominant school of thought in early-twentieth-century child-rearing valued scientific rigor over intuition and tradition; kissing your baby excessively, much less nursing her, came to seem suspect. Even so, some authorities endorsed the medical value of breast-feeding. In 1937, Ladies’ Home Journal published an article headlined “Babies Should Be Breast-fed,” written by Dr. Herman N. Bundesen, the president of the Chicago Board of Health. Bundesen used public-health statistics to make his case: “Out of every ten babies who die in the first year of life, eight are bottle fed—not breast fed.” (Don’t kill your baby!)

Yet imperatives like Bundesen’s rarely translated into meaningful support for women interested in breast-feeding, as Jessica Martucci, a historian of medicine at the University of Pennsylvania and the author of “Back to the Breast,” a study of breast-feeding’s postwar resurgence, has argued. By the nineteen-forties, most mothers were giving birth in hospitals, where orderly routine—babies in nurseries, bottles on schedules—often took priority over the personal attention required to initiate breast-feeding. Sometimes the discouragement was still more direct: into the sixties, some hospitals treated maternity patients with hormonal “dry-up pills.”

Under these circumstances, mothers who wished to breast-feed were often obliged to figure it out for themselves. Niles Polk Rumely Newton, a Columbia-trained psychologist who wrote a popular mid-century child-rearing book, breast-fed her children with help from her mother, but she was troubled by the lack of official guidance. With her obstetrician husband, she devised a series of experiments based on research performed on cows, and she used herself as a test subject. Newton helped to establish the workings of the human “let down” reflex, a hormonal process that prompts the release of milk in response to a baby’s suckling. Basically, a mother had to be able to relax. (A beer could help, the Newtons suggested.) “In the dairy business,” a 1955 Ladies’ Home Journal article on the Newtons noted, “the farmer’s loss can be measured in dollars and cents; perhaps for this reason, far more research has been concentrated on lactation in cows than in humans.”

Commercial infant formula from brands such as Similac and Enfamil took off in the fifties—a modern amenity that sat comfortably alongside Betty Crocker cake mix and Cheez Whiz. (Formula had also made it easier for women to work outside the home.) At the same time, the decade saw the rise of some of breast-feeding’s most influential evangelists. The La Leche League was founded in 1956 by seven Catholic housewives in the Chicago suburbs who wanted to create a forum for breast-feeding mothers to share questions and advice. La Leche occupied a tricky cultural position, at once radical and conservative: on the one hand, it encouraged women to claim control of their bodies and to defy voices of institutional authority; on the other, the intended result of this rebellion was a world in which a mother’s place was unequivocally at home. Still, the appetite for practical help was ravenous. Within twenty years of its first meeting, La Leche had grown to include almost three thousand chapters.

National breast-feeding rates reached their lowest ebb in the early seventies, with only twenty-two per cent of mothers even trying to nurse in 1972. But a shift was already taking place. Feminists sparred with La Leche over its stance on working mothers, yet they, too, sought to empower women facing down the medical establishment. Countercultural currents produced a generation of parents more inclined to feed babies the natural way. In a “Sesame Street” segment from the era, Buffy Sainte-Marie, the singer and Indigenous activist, breast-feeds her baby while Big Bird looks on. It’s “nice and warm and sweet and natural,” Sainte-Marie explains. “And I get to hug him while I do it, see?” It was also an activity with the power to, among other things, épater le bourgeois. “Breast Feeding in Public a Growing Trend,” the Times reported in 1973. As one woman told the paper, “Neither I nor my husband want to go out to dine and be faced with someone’s breast. It’s only happened to us once but let me tell you, it was enough. . . . My husband almost dropped his martini.”

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