Biotech milk formula - health potential quashed by safety laws

Genetically modified rice carrying a protein from human breast milk is being developed by US biotech companies to enhance baby formula, even though it is currently illegal in America to use a GM protein in baby food, reports Nature​.

Nutritionists have long established that breast milk is better for babies, and have campaigned to promote breast feeding in the third world. Aiming to make milk formula more like human milk, the biotechnology industry has tried engineering crops or animals to produce human breast milk proteins.

Nature reports that Yuriko Adkins of the University of California, Davis and her colleagues, have modified rice plants to carry a human gene for the milk enzyme lactoferrin, needed by babies to use iron efficiently and fight infection.

Rats fed the rice-raised 'recombinant' enzyme together with a second enzyme, lysozyme, were better able to kill gastrointestinal bacteria, Adkins told the Experimental Biology 2002 meeting in New Orleans, US last week. While sterilisation inactivates the lactoferrin in current cow-based infant formula, the GM form is stable.

However the US Food and Drug Administration (FDA) will not approve the recombinant protein, warned Steve Taylor of the University of Nebraska, who has been involved in worldwide GM food committees.

The FDA's regulations are designed to cover biotech plants that carry drugs or pesticides. They will have to be rethought before rice-grown lactoferrin, and other human proteins made by genetically modified organisms, can be approved for production, said Taylor.

Researchers may be able to bypass the regulatory process if they can prove that the recombinant protein acts identically in the gut to the human one. The two might then be treated as the same, claimed Todd Stoltz of Ventria Bioscience, the company planning commercial production of the human proteins in rice.

The recombinant proteins have been developed with particular functions in mind, such as in milk formulas to enhance premature babies' nutrient absorption or to help newborn babies fight HIV. (HIV-positive mothers are advised against breast-feeding by the World Health Organization.)

"These proteins are out there by the tonne,"​ said Bo Lonnerdal, from the University of California, Davis. Human breast-milk proteins are already experimentally produced in several different organisms yet their functions are still unclear, notes the report.

For example, there are no animal models that adequately mimic human allergy, and it is unclear whether an animal's response to a human protein is comparable to that of a person.

There is also no guarantee that consumers will accept humanised biotech milk and they may be particularly concerned about feeding GM food to their baby, added Lonnerdal.