UNC Greensboro study could change how critically ill infants are fed

A landmark international study conducted by UNC Greensboro researchers has found "significant variations" in the nutritional composition of donor human milk across five countries.

The findings could transform how hospitals support critically ill preterm infants worldwide, according to lead researcher Dr. Maryanne Perrin, an associate professor of nutrition.

"Donor human milk serves as a lifesaving feeding alternative for preterm infants when a mother's own milk is unavailable, significantly reducing the risk of necrotizing enterocolitis — a devastating intestinal condition," Perrin said.

"Our study reveals current clinical protocols around donor human milk may require substantial revisions that vary based on the profile of a milk bank's donors."

The study has been published in the American Journal of Clinical Nutrition.

The researchers collected and analyzed 600 milk samples from approved donors across eight milk banks in Chile, Kenya, Poland, Vietnam and the United States.

"This represents the largest and most geographically diverse study of donor human milk composition to date," Perrin said. "In particular, the study fills knowledge gaps by including low- and middle-income countries with high preterm birth rates.

"This is a population that didn't exist 30 years ago; babies that were born around 24 weeks didn't survive."

"That has implications for how we feed our most vulnerable infants. This is in line with other studies of human breast milk."

Almost all the countries studied used a mature donation model, where donations occurred an average of 14 to 21 weeks after delivery.

These donations had higher concentrations of lactose and several B-vitamins including thiamine, niacin, B6 and pantothenic acid.

However, Kenya used an early donation model with milk donations sourced from donors at an average of 1.6 weeks after delivery.

Those samples had 30% to 50% higher protein concentrations — an especially important nutrient for preterm infant growth.

They also had higher concentrations of several minerals, including potassium, sodium, copper, iron, selenium and zinc, as well as increased human milk oligosaccharides, which help the immune system develop.

Perrin said it is important to note that more than half of donors in Kenya experienced preterm deliveries.

Researchers noted other regional differences in vitamins that may be related to the dietary patterns of the donors.

Among the countries using mature donation models, they found relatively higher riboflavin and lower choline levels in samples from the U.S., lower B12 in Poland, and lower thiamine in Vietnam. Choline is a nutrient that's vital for cell membranes and brain function.

"Over 60% of nutrient variation we saw in donor milk remains unexplained by lactation stage, birth term, maternal age, donation volume or storage duration," Perrin said.

"In addition to fortification, we must investigate other strategies, such as multi-donor pooling to reduce variation.

"For now, the unpredictability means continuing challenges to ensuring consistent nutrition for the 15 million preterm infants born each year, many who are nutritionally vulnerable."