Today breast milk is recognised as a sort of liquid miracle for babies, but history is full of periods where people swapped in other things in its place. In the 15th century, it was cow and goat milk. In the 18th century, it was cereal or flour mixed with broth. More recently, it was baby formula. For reasons of convenience or in search of better nutrition, humans have long sought to one-up a mother's milk.
Synthesized breast milk sugars. Image: Sugarlogix
Now one Silicon Valley startup wants to disrupt breast milk, not by creating a formula substitute, but by isolating the sugars that make breast milk so unique and turning those sugars into a product for infants and adults alike. Those sugars, the company claims, could be the next big health craze. The science behind breast milk, though, is still too young to tell whether it might really be an immune-boosting superfood supplement or just another soon-to-be-debunked fad.
In recent decades, breast feeding has experienced a resurgence, helped in large part by science that suggests breast milk is a boon to a baby's immune system. Not only does breast milk contain the vitamins and nutrients that a newborn needs, it also contains sugars that serve as medicine, helping to ward off infection by feeding beneficial bacteria. Scientists have identified more than 200 different sugar molecules, or human milk oligosaccharides (HMOs), in humans, far more than the 50 or so found in other mammals. After lactose and fats, those sugars are the third most plentiful ingredient in human milk. But humans of all ages lack the enzymes to process those sugars. Instead, most of those sugars pass through the stomach and into the small intestine, undigested.
Studies suggest why: In 2006, one research team found that, in the lab, the sugars nourish one particular subspecies of bacteria, Bifidobacterium longum infantis, a bacteria which in turn raised the acidity of the substrate as it fed off of the HMOs. In the infant gut, it's possible the same rise in acidity occurs, which would make the environment more hostile to pathogens like E.Coli. The bacteria B. infantis also encourages the production of proteins that close the gaps between gut cells to keep microbes out of the bloodstream and of anti-inflammatory molecules that boost the immune system. And to get those benefits, it appears that B. infantis needs to feed on the sugars found in breast milk.
But not every woman can easily produce breast milk. So naturally, all this research into the potential benefits of breast milk has spurred a rush of companies hoping to synthesise the ingredients in breast milk in order to one day perfectly mimic in formula the stuff from mum.
One of those companies is Sugarlogix, a Berkeley biotech startup that recently graduated from the Indiebio startup accelerator. Sugarlogix is working to synthesise the sugars found in breast milk.
"We were interested in prebiotics and we realised that the best type of prebiotics exist in nature, and that's in human breast milk," Kulika Chomvong, CEO of Sugarlogix, told Gizmodo. Like probiotics, prebiotics are foods that cannot be digested by the human body. But while probiotics contain live bacterial cultures, prebiotics are the stuff that cultivates and feeds that bacteria.
Sugarlogix is working on developing sugars for babies that are not breast-fed -- they say they have a deal in the works to start supplying one infant formula company with its sugars when Sugarlogix scales up production next year.
But babies are just the logical starting point for a vision that's much grander: the benefits of breast milk, for grownups.
Chomvong said that Sugarlogix plans to turn its powder-form sugars into a pill, a prebiotic you might take every day the same way you do a multi-vitamin.
"This is the very first time adults can really harness the power of breast milk," Chomvong said. "We wanted to find the very first food for the gut that we ever received as babies, and that's breastmilk."
Our bodies, including, perhaps most notably, our gut, are home to an entire community of microorganisms, which science increasingly suggests plays a major role in human health. Evidence suggest that gut bacteria can affect disease, mental health and even athletic ability. In one significant study earlier this year, researchers traced the origin of a brain disorder to a particular type of bacteria living in the gut.
The sugars in breast milk feed B. infantis, helping to cultivate a healthy microbiome. Breast milk isn't just a superfood for baby -- it's also a superfood for the baby's microbiome.
The question, though, is whether that superfood would do any good in the grownup microbiome. Infants are born with a sterile, bacteria-free gut. It's only in the first weeks of life that their guts become seeded with the myriad bacterial species that will flourish there throughout their lives. So while HMOs might be the key to jumpstarting bacterial colonies in the pristine environment of an infant's gut, it's unclear whether the process would work exactly the same way in adults, who already have thriving bacterial colonies.
Michael Miller, a microbiologist at the University of Illinois who has studied human breast milk, said that the benefit of synthesizing sugars for infants is still not even clear, let alone for adults.
"Different mum's milks will have different compositions. It's too complex to fully replicate," he told Gizmodo. "Some of the more simple sugars that are most common in mum's milks we can now make somewhat economically. But it's not yet clear whether these more simple sugars will give you some of the benefit of breast milk sugars, or whether the real benefit is having the full complexity that exists in a mum's milk."
Miller said that part of what makes studying human milk so interesting is that the findings could provide insight into the adult microbiome, too.
"There is evidence suggesting that breast milks provides resistance to infections to infants. Maybe an adult could benefit from that," he said.
Miller said, though, that at this point that idea is mostly conjecture. And, if a person did benefit, it would likely come in the form of taking a pill for a specific purpose, rather than like a daily vitamin.
And while the volume of research into human breast milk is growing, it's still exceptionally small compared to almost any other human biological function. There's a lot we don't know about how breast milk nourishes infants, much less how isolated HMOs might impact adults.
"Based on emerging research, human milk oligosaccharides seem to be main drivers in shaping the developing infant gut microbiome, with potential short- and long-term consequences for human health and disease," said Lars Bode, whose UC San Diego lab is dedicated to the study of human milk sugars and has probably published more than any other researcher on the subject.
Bode said HMOs could also be beneficial for adults by helping to re-shape the gut microbiome to guard against pathogens or treat disease. But like Miller, he stressed that all this is still little more than hypothetical.
"Overall, [there is] a lot of potential in both infants and adults, but a lot more work is needed to substantiate and confirm claims," he told Gizmodo.
Sugarlogix does cite a 2016 study (funded by another company synthesizing human milk sugars) that found that the sugars did not have negative side effects and led to an increase of another gut bacteria in the same genus as B. infantis.
And B. infantis, the bacteria that HMOs promotes in infants, has been found to be low in quantity in patients with conditions such as type II diabetes and irritable bowel syndrome. The research is still in early days, but some researchers have suggested increasing the quantities of that bacteria could help mitigate symptoms in people with diabetes. And if a synthetic blend of HMOs could help increase this bacteria in an adult's gut, then it's possible it could help alleviate symptoms.
Though current research only suggests narrow potential indications, Chomveng believes the sugars could someday gain traction with a broad swath of adult consumers. She told me that the company hopes to eventually sell its sugars to food producers, too, fighting disease one over-priced Greek yogurt at a time. But that's a long-shot dream in a field where research is still mostly preliminary.
Of course, breast milk pills could go the way of breast milk cheese -- yet another weird health fad no one will want to remember.