The Next Thing In Gut Health Is Going To Be Sugar Made From Human Breast Milk

You may not have heard of human milk sugar, but it does great things for your microbiome. Scientists have figured out how to synthesize it, and it’s coming to your grocery store soon.

The Next Thing In Gut Health Is Going To Be Sugar Made From Human Breast Milk
“If we consume [human milk sugars], the population of the good gut bacteria increases, out-populating the bad bacteria.” [Photo: John Howard/Getty Images]

Your mixed berry yogurt may eventually include not only probiotics but a type of sugar usually found only in human breast milk.


In babies, sugars known as human milk oligosaccharides, or HMOs, play a key role in health. A California-based startup is one of a handful of companies trying to manufacture the sugars outside the human body–both to produce healthier infant formula for babies who can’t breastfeed, and to potentially improve health in adults as well.

Unlike typical sugar found in food, human milk sugars can’t be digested by people and don’t make food sweet; instead, they feed beneficial bacteria in the gut. “If we consume them, the population of the good gut bacteria increases, out-populating the bad bacteria that could also reside in your body,” says Chaeyoung Shin, one of the cofounders of Sugarlogix, a startup making a particular type of human milk sugar called 2′-fucosyllactose, or 2′-FL. “This leads to a healthier digestive system, healthier gut, which will then help in boosting your immune system as well.”

“It’s telling the immune system what’s, in a sense, a good bug and a bad bug.” [Photo: Or Weizman]
Shin and cofounder Kulika Chomvong met at the University of California-Berkeley’s Energy Biosciences Institute while working on a different problem: producing biofuel. Chomvong, a microbiologist, engineered yeast that could produce fuel from cellulose, and Shin, a chemical engineer, worked on improving the biofuel fermentation process. But after completing their PhD programs, they decided to shift course. “After the crash in fuel price, it didn’t seem like a good idea anymore, nor did it seem viable in the next 20 to 50 years,” says Shin. “So then we decided to look for a higher-end product.”

Human milk sugars, which can be cultured through yeast fermentation–in a similar process to making biofuel or brewing beer–seemed like a good fit. In breastfed infants, the human milk sugars help build up bifidobacterium in the gut, one of a few bacteria that can digest the complex sugars. The bacteria help make the gut more acidic, which “prevents E. coli and bugs like that from getting an early foothold,” says David Mills, a professor of food science and technology at the University of California-Davis who studies the oligosaccharides. “It’s telling the immune system what’s, in a sense, a good bug and a bad bug.”

In adults, low levels of bifidobacterium have been found in patients with diabetes and other diseases such as irritable bowel syndrome. When the gut microbiome–the ecosystem of trillions of bacteria living in the intestinal tract–is unbalanced, it has also been linked to cancer risk, Parkinson’s disease, and anxiety and depression, among other diseases.

Eating junk food quickly affects the gut microbiome; in one study, a group of rural Africans who temporarily shifted from a healthy diet to burgers and fries showed both a marked change in gut microbes and an increase in biomarkers of cancer risk after only two weeks. In addition to shifting to a healthier diet, the scientists say that probiotics–such as bifidobacterium, which is added to some foods like yogurt–might help. And though there’s little research to back it up so far, the theory is that a supplement of human milk sugars, part of a class of ingredients known as prebiotics, could help those probiotics work better.


[Photo: Or Weizman]
“When you consume probiotics, what you’re consuming is the good gut bacteria themselves,” says Shin. “You’re consuming the living organisms. However, since they are living organisms, they need the right kind of food source, and the right kind of food source for them is prebiotics. We believe that you need both–the good gut bacteria and the food source–in order for them to thrive and to make a healthy gut microbiome.”

A 2016 study (notably, funded by another company synthesizing human milk oligosaccharides) found that HMO supplements in adults led to an increase in beneficial bacteria in the gut and appeared to be safe and well tolerated.

Sugarlogix plans to initially offer supplements for adults, and then offer its product as an additive in foods that already target gut health, such as yogurt and kombucha. It also plans to produce the sugar as an ingredient for infant formula. “It’s known as the holy grail of ingredients for baby formula,” says Shin.

While infant formula is unlikely to become as healthy as breast milk–which delivers antibodies from the mother to the baby, along with antimicrobial proteins and fatty acids, along with as many as 130 different kinds of the milk sugars–adding one of the sugars could help. A 2016 study from researchers at Abbott, the company that makes the baby formula Similac, found that when babies were fed formula with 2′-FL, the same HMO that Sugarlogix produces, they had an immune response more similar to breastfed babies. Similac now offers a version of formula with the ingredient.

Some other producers create the sugar using modified E. coli bacteria, but Sugarlogix believes that its method, using yeast, is a better approach. E. coli produce endotoxins that have to be filtered from the resulting sugar, adding expense and potential risk.

“The advantage of producing with yeast is that it has been known to be a food-friendly organism for thousands of years, meaning it does not produce any toxins, which could increase the separation cost and potentially be a food-safety risk,” says Shin. “We start out with bakery yeast, make genetic changes so that it produces HMOs–this is the technology that separates us from our competitors. In other words, currently we are the only ones who know how to produce HMOs with yeast.”


The startup is part of the current class at IndieBio, a San Francisco-based accelerator for biotech companies, and is raising a seed round of investment.


About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley.