| NEW YORK
NEW YORK (Reuters Health) - Breast milk helps protect premature babies from potentially fatal complications, but a new study shows that donated breast milk, meant to supplement what the mother provides, may lack key nutrients.
Researchers found that donated breast milk did not contain enough of a fatty acid that tiny babies need for their developing nervous system, and also lacked amino acids, the building blocks of proteins.
Encouragingly, they also found that pasteurizing donor milk -- needed to kill any lingering microbes, which could be deadly to preemies with developing immune systems -- did not affect any nutrients, suggesting this step doesn't strip donor milk of what preemies need.
"We were very reassured" that pasteurization didn't affect donor milk, study author Dr. Christina Valentine of Nationwide Children's Hospital in Ohio told Reuters Health.
Even if donor milk contained too few amino acids and too little of the fatty acid docosahexaenoic acid (DHA) for preemies, Valentine explained, the levels could still be high enough for normal-term babies, who drink a lot more milk and therefore likely receive all the nutrients they need.
Dr. Hawley Montgomery-Downs, who was not involved in the study, said women's bodies have an amazing capacity to adapt to their babies' requirements.
"The woman is producing milk for her baby that is just right for the baby at that age," said Montgomery-Downs, of West Virginia University. Milk expressed for a normal-term baby may simply be somewhat inadequate for a preemie's higher nutritional needs, she explained.
What is unknown, she added, is whether mothers of preterm babies produce more fatty acids and amino acids to supply their babies' extra needs.
Valentine and her team are currently investigating whether adding protein powder to donor milk boosts the amino acid content. But when it comes to DHA, it's not as simple as just supplementing donor samples, she said, since extra fatty acid could displace the balance of other nutrients.
Instead, her team is testing whether asking moms to eat more DHA -- from sources such as fish, algae, and eggs of chickens fed extra DHA -- improves the fatty acid content of their breast milk.
"As we become less of a fish-eating society, breast milk levels are getting low in this essential nutrient," Valentine said.
The milk tested in the study, published in the Journal of Pediatrics, came from Mother's Milk Bank of Ohio, one of several milk banks across North America that collect breast milk from women who donate their extra supply for no compensation.
"They save a lot of babies' lives." Montgomery-Downs said. "For prematurely born infants, milk is medicine."
The science backing breastfeeding is clear: Breastfed babies are healthier and less susceptible to disease. And they might have better brain development.
Research shows breast milk can be particularly beneficial for very tiny babies, helping prevent an intestinal disorder called necrotizing enterocolitis, which in some cases may be fatal.
Many mothers of premature babies do breastfeed, Valentine said, but some can't express enough milk, perhaps a result of an underlying condition that caused them to deliver prematurely. Those mothers often opt to supplement their babies' nutrition with donor milk.
For all its benefits, donor milk doesn't come cheap. It costs typically $4 per ounce, depending on the bank (insurance may cover some of the cost), and preemies will often require hundreds of ounces.
To test whether donor milk contains what preemies need, Valentine and her colleagues tested milk samples from 39 donors before and after pasteurization.
Pasteurization had little effect on nutritional content. But the milk contained about 50 milligrams less DHA than what premature babies would have gotten daily while still in the womb. It also contained fewer amino acids than previously found, and the total protein levels, even with fortification, appeared to be less than what preemies require.
The pasteurization process they used -- heating human milk to 62.5 degrees Celsius for 30 minutes -- matches the guidelines for North America, but not for other regions, Valentine noted, and different types of pasteurization may still affect milk nutrition.
SOURCE: link.reuters.com/geq97q The Journal of Pediatrics, December 2010.