the New Science of Artificial Breast Milk
Not long ago, I suited up in a white coat and safety goggles and entered a quiet laboratory where an experiment at the frontiers of science and parenthood was under way
A young engineer with a tidy beard escorted me past rows of benches to a large freezer.
He opened it to reveal an array of ice-caked steel drawers and, wearing blue Cryo-Gloves (reverse oven mitts, essentially), removed a small bottle from the chill, which measured minus eighty degrees Celsius.
At the bottom of the bottle, two hundred and fifty millilitres of liquid had formed a shallow, colorless puck.
I was visiting Biomilq, a startup, founded by Leila Strickland and Michelle Egger, that is working to produce lab-grown breast milk. Biomilq’s headquarters are in North Carolina’s Research Triangle Park, a seven-thousand-acre wedge of pine forests and office complexes between Durham, Chapel Hill, and Raleigh.
The bottle creaked as it began to adjust to the room’s warmth, and the engineer hastened to put it back in the freezer.
You could call the bottle’s contents Biomilq, or maybe just milk, or, as the engineer did—indicating a number of smaller bottles also stowed in the freezer—“our best shots to date.”
The frozen puck represented a week and a half’s worth of output from a single line of lab-cultured human mammary cells. The company hopes to use these cells and others like them to re-create as closely as possible the process of making human milk.
About three years before my visit, in February of 2020, Biomilq announced that it had successfully used cells to produce lactose and casein, a sugar and a protein found in breast milk.
“Our opinion as a company—and most of us internally, too—is that breast-feeding, at the breast, has benefits that no one will ever be able to mimic,” Egger, a food scientist turned entrepreneur, told me. “If you can breast-feed—do it. Great. But the reality is, a majority of parents cannot exclusively breast-feed. . . . And that’s not for lack of trying.”
Breast milk is often described as a kind of elixir—“perfect nutrition,” in the words of a 2015 paper in Early Human Development. The health benefits that have been attributed to breast milk include protection against asthma, diabetes, diarrhea, ear infections, eczema, obesity, and sudden infant death syndrome.
Some much cited research also credits breast milk with producing smarter children, although this is difficult to substantiate. Tabulating a complete science-backed list of the advantages of breast milk over infant formula can be a challenge.
The available data are limited by a lack of structural support for breast-feeding. There are, for example, statistical concerns about comparing parents who can’t undertake the time-intensive process of breast-feeding with those who can. (Studies tend to show that parents who breast-feed are more educated and affluent than parents who don’t, and thus confer other benefits on their children.)
Regardless of the precise details of breast milk’s advantages, it remains the widely acknowledged gold standard in infant nutrition; to replicate it in a laboratory would be alchemy. On a neon sign in Biomilq’s office, the words “Making Magic” hang beneath the curve of a decorously abstract lactating breast.
In a conference room labelled “Skim,” I met with Strickland, a mother of two with cropped wavy hair and a soft lisp. On one wall was a series of photographs, by Sophie Harris-Taylor, that depict nursing mothers in various states of domestic weariness and serenity.
The photos were among the first things that Egger bought for Biomilq’s workspace—a purchase in keeping with the company’s efforts to build a mom-forward brand. At the heart of those efforts is Strickland’s own experience with breast-feeding.
Fourteen years ago, Strickland, then a postdoctoral fellow in cell biology at Stanford, became pregnant. At the time, she lived near Santa Cruz, a beach town in Northern California where a particular goddess-mama vibe around maternity prevailed.
“Culturally, there was a lot of promotion of, like, ‘You want to do a natural birth, you don’t want an epidural,’ ” she told me. “You know, ‘Your body is made for this.’ ”
To some extent, Strickland embraced that attitude. She certainly planned to breast-feed. But the first weeks of her baby’s life called those expectations into question. “When you find, actually, my body is not making enough milk for my baby—what’s up with that?” she said. “Is my body actually not made for this?”
Strickland began to think of her struggle, a not uncommon one, as a scientific challenge. Then, in 2013, a tissue engineer named Mark Post unveiled a hamburger made from lab-grown beef.
Produced at a cost of some three hundred and twenty-five thousand dollars, it tasted, in Post’s words, “reasonably good,” and helped to kick off a period of burgeoning interest among investors in “cellular agriculture,” an area of biotechnology devoted to finding lab-grown alternatives to conventional agricultural products.
Startups were using engineered yeast to generate animal proteins, or were culturing animal cells directly. Strickland and her husband, a software developer, were excited about the possibilities. What if there were a way to generate breast milk from cells in a lab?
They had moved to North Carolina a few years earlier, and Strickland started to experiment using tissue from a cow udder and secondhand lab equipment. In 2019, a mutual friend introduced Strickland to Egger, a Duke M.B.A. student focussed on social entrepreneurship.
(Strickland and her husband are now separated. They are currently litigating disputes over the product and its name, ownership, genesis, and technology. He continues to operate an L.L.C. that they formed together, 108Labs, through which he is pursuing lab-grown milk products on his own.)
Egger has a sign in her office that reads “Wake me when I’m CEO.” She spent her early career at General Mills, where she helped develop such products as Lärabar, Go-Gurt, and low-sugar bulk yogurt for schools.
While training as a food scientist, Egger had planned to avoid working on dairy—she has hyperosmia, a heightened sense of smell, and the world of bovine odors was uninviting—but the field’s complexity drew her in. “Dairy research is a little bit of art and science combined,” she told me. “Often we do things not because we know why it works but because we just know that it does.” Egger became Biomilq’s C.E.O.
In 2020, 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 2021, they closed a twenty-one-million-dollar series-A funding round.
Then, in 2022, 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.
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.
This is taken from a long article. Read the rest here newyorker.com
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