The demand for donor breast milk has increased, and many parents are paying a hefty price for human breast milk or seeking out donors through milk exchanges on social media. While the safety of these practices has come under question, now donor breast milk nutrition is also under scrutiny.
A new study from the University of Rochester indicates all the nutrients newborns need may not be found in donor milk. The study examined milk from 138 samples of donated human milk from the Mother’s Milk Bank in Colorado. The results from the analysis confirmed previous research that donor milk had lower caloric density than expected.
The milk also showed a specific deficit in Zinc. The nutrient Zinc plays a large role in babies’ growth and development, so its lack in donor milk is a cause for concern for parents supplementing at home. The concentration of Zinc naturally decreases in a mother’s milk the further away she is from giving birth. Since donors circumstances vary greatly, so do the nutrients in their milk.

That should not deter parents wanting to use donor milk, according to Bridget E. Young, PhD, CLC, an author of the study. Young tells Parentology, “Donor milk is a lifesaving source of nutrition, especially for premature infants. Donor milk is routinely fortified for premature babies to meet their elevated nutrient needs. This fortification overcomes the lower value of protein and zinc observed in many donor milk pools.”
Indeed, hospitals and NICU’s use fortifiers with all donor breast milk to ensure babies receive the correct amount of calories and nutrients.
Lactation expert Andrea Tran, RN, MA, IBCLC is the former lactation coordinator of Boulder Community Health (BCH), a depot for the Mother’s Milk Bank in Colorado, weighs in with Parentology, “Research has shown when used in premature babies, human donor milk results in much lower rates of the deadly disease Necrotizing Enterocolitis.”
Tran continues, “Furthermore, infants fed milk that was not breast milk have higher rates of asthma. Human milk that’s been pasteurized still retains important factors like oligosaccharides and antibodies.”
To ensure your baby is getting what they need nutritionally, Young recommends working closely with your pediatrician to discuss individual circumstances. “Things like how old the baby is, how much donor milk the baby is drinking, whether the baby is also receiving formula or mother’s milk, and how much of each are all things that matter. Your pediatrician knows the individual characteristics of your baby and will help navigate these questions.”

The University of Rochester study focuses on breast milk from a certified breast milk bank. “We don’t recommend families purchase breast milk from the internet since it is not regulated at all,” Young says. “All the issues with nutrient variation still apply there. Also, milk banks screen donors and pasteurize the milk to ensure it is safe for medically fragile babies. Obviously that safety isn’t guaranteed when exchanging milk privately.”
This new research may help certified milk banks ensure that their breast milk is affording babies the nutrition they need. The Human Milk Banking Association of North America (HMBANA) recommends parents consult with their child’s doctor to make sure their baby is getting the needed nutrients from any donor breast milk.
Donor Breast Milk Nutrition — Sources
University of Rochester
National Center for Biotechnology Information
Andrea Tran, RN, MA, IBCLC
Bridget E. Young, PhD, CLC