Friday, May 28, 2010
Human Milk and Milk Supplements Protect Newborns
Babies born prematurely are at risk of a serious bacterial infection of the intestines, necrotizing enterocolitis (NEC), that can be prevented if formula based on cow’s milk products is avoided and human milk is used for all feedings.
Human Milk Protects Against Formula Based NEC
Feeding low birth weight, premature babies formula made from cow’s milk increases their risk of NEC ten fold. Replacement of some of the cow’s milk formula with human milk from a milk bank reduces NEC.
Human Milk and Cow’s Milk Are Very Different
What is present in human milk that protects against NEC? The major components in milk are proteins, lactose, fats and oligosaccharides (short to medium length chains of sugars.) Human milk and cow’s milk have the same amount of fat (35 grams/liter) and about the same amount of lactose (65 vs. 45 g/l) and protein (10 vs. 35 g/l). The big difference is in the amount (5-10 vs. 0.05 g/l) and quality of oligosaccharides. Human milk has more than 100 times the amount of oligosaccharides as cow’s milk. That also means that about 10% of the carbohydrates in human milk are non-nutritive human milk oligosaccharides (HMOs).
HMOs Are Not FOS
Human milk oligosaccharides are complex, with over 200 different structures identified so far. Essentially they are made up of a lactose (a disaccharide consisting of galactose linked to glucose) extended by different numbers of N-acetyllactosamine (lactose with a modified glucose) and a few other sugars attached a various locations. A different enzyme is used for each modification and the synthesis of these oligosaccharides has not yet been figured out in detail. More than a dozen different genes are devoted to the synthesis of these oligosaccharides. These oligosaccharides are not structurally or functionally related to the frucose oligosaccharides used as prebiotics.
HMOs Are Prebiotic and Stop NEC
Human milk oligosaccharides have been tested both for their ability to act as prebiotics to encourage the development of normal baby gut flora and to suppress NEC. The HMOs were found to be the elusive bifidus factor that stops the development of adult gut flora and facilitates only the development of the Biﬁdobacterium biﬁdum monoculture found in exclusively breastfed babies. HMOs also reduce NEC in the same way as whole human milk. Another interesting aspect of HMOs is that they modify the oligosaccharides produced on the surface of baby intestinal cells. Babies fed human milk also secrete HMOs in their urine, indicating that ingested HMOs are absorbed in the intestines and reach the blood stream.
Neonatal Nurseries Should Use Only Human Milk
Human milk is now available to neonatal intensive care nurseries through milk banks and purified components of human milk are also available to supplement feedings for very low birth weight premature babies. Nursing is still best for baby and mother, but those mothers who choose not to nurse need not compromise the health and development of their babies by using cow’s milk-based formula or supplements. Every dollar spent on pasteurized donor milk ($3/oz.) reduces costs in neonatal intensive care units by more than ten dollars. It seems to be time to eliminate the added risks of formula use in hospitals and provide every baby with a healthy start and normal gut flora by only using human milk products in hospitals.
Lars Bode. 2009. Human milk oligosaccharides: prebiotics and beyond
Nutrition Reviews® Vol. 67(Suppl. 2):S183–S191