Critical Nutritional Variations in Donor Human Milk for Preterm Infants

A recent study highlights significant disparities in the nutritional content of donor human milk, which carries important implications for the care of preterm infants worldwide. Conducted by researchers at the University of North Carolina at Greensboro (UNCG), the findings suggest that existing clinical practices regarding donor human milk may need substantial revisions based on the characteristics of the milk bank's donor population.

The research, published in the American Journal of Clinical Nutrition, involved the analysis of 600 milk samples from approved donors at eight milk banks located in Chile, Kenya, Poland, Vietnam, and the United States. The study's lead researcher emphasized the critical role of donor human milk as a feeding alternative for preterm infants when mothers are unable to provide their own milk, significantly lowering the risk of necrotizing enterocolitis, a serious intestinal condition.

The analysis revealed that the nutritional profile of donor milk varies considerably based on whether the milk is sourced from donors in early or mature lactation stages. This variation has significant implications for feeding strategies for vulnerable infants. Most countries in the study utilized a mature donation model, where milk was donated an average of 14 to 21 weeks after delivery. This model yielded milk with higher concentrations of lactose and several B vitamins, such as thiamine, niacin, vitamin B6, and pantothenic acid.

In contrast, Kenya's milk bank employed an early donation model, sourcing milk from donors an average of just 1.6 weeks post-delivery. This resulted in samples with protein concentrations that were 30 to 50 percent higher, an essential nutrient for the growth of preterm infants. Additionally, the Kenyan samples contained elevated levels of minerals like potassium, sodium, copper, iron, selenium, and zinc, along with an increase in human milk oligosaccharides. Notably, more than half of the donors in Kenya had experienced preterm deliveries themselves.

Regional disparities in vitamin content were also observed, which may be influenced by the dietary habits of the donors. Among the countries practicing mature donation, the U.S. samples showed relatively higher riboflavin levels and reduced choline, while Poland had lower vitamin B12 levels and Vietnam had diminished thiamine levels.

Researchers indicated that donor human milk is typically fortified to ensure that preterm infants receive optimal nutrition. However, the study's findings suggest that fortification strategies could be tailored to align with specific regional and milk bank models to enhance nutritional consistency.

Despite these findings, the researchers acknowledged that a significant portion of nutrient variation--over 60 percent--remains unexplained by factors such as lactation stage, birth term, maternal age, donation volume, or storage duration. This unpredictability continues to present challenges in providing consistent nutrition for the approximately 15 million preterm infants born globally each year, many of whom are nutritionally vulnerable.

The study's authors included experts from various institutions, reflecting a collaborative effort to address knowledge gaps regarding donor human milk composition, particularly in low- and middle-income countries with high preterm birth rates. This research marks a significant advancement in understanding the nutritional needs of preterm infants, a population that has seen remarkable survival rates in recent years.