Engineered plants produce human milk sugars that could lead to healthier baby formula

Worldwide, a majority of babies – approximately 75% – drink infant formula in their first six months of life, either as a sole source of nutrition or as a supplement to breastfeeding. But while formula provides essential food for growing babies, it currently does not replicate the full nutritional profile of breast milk.

That's in part because human breast milk contains a unique blend of approximately 200 prebiotic sugar molecules that help prevent disease and support the growth of healthy gut bacteria. However, most of these sugars remain difficult – if not impossible – to manufacture.

New research led by scientists at the University of California, Berkeley, and the University of California, Davis, shows how genetically engineered plants may help close this gap.

In a new study published today in the journal Nature Food, the study team reprogrammed plants' sugar-making machinery to produce a diverse array of these human milk sugars, also called human milk oligosaccharides. The findings could lead to healthier and more affordable formula for babies, or more nutritious non-dairy plant milk for adults.

To convince plants to make human milk oligosaccharides, study first author Collin Barnum engineered the genes responsible for the enzymes that make these specific linkages. Working with Daniela Barile, David Mills and Carlito Lebrilla at UC Davis, he then introduced the genes into the Nicotiana benthamiana plant, a close relative of tobacco.

The genetically modified plants produced 11 known human milk oligosaccharides, along with a variety of other complex sugars with similar linkage patterns.

Image source: Barnum et al. (2024), Nature Food.