Researchers Examine Human Breast Milk Ingredient
May 15, 2012

Researchers Examine Human Breast Milk Ingredient

Connie K. Ho for

A report by the University of Illinois (UI) demonstrates that human milk oligosaccharides (HMO) can create short-chain fatty acids that can help beneficial microbial populations in an infant´s gut. The bacterial composition can alter itself as the baby grows older and its needs change.  Based on the fact that HMOs are a large part of human milk and absent from infant formula, the researchers wanted to better understand what formula-fed babies were not receiving.

Published in the April issue of the Journal of Nutrition, the study was funded by a grant from the National Institutes of Health (NIH). The researchers worked to identify HMO´s actions in the infant. Sharon Donovan of UI was one of the lead researchers on the project who wanted to demystify the influences of HMO.

"We refer to HMO as the fiber of human milk because we don't have the enzymes to break down these compounds. They pass into the large intestine where the bacteria digest them,” commented Donovan, the Melissa M. Noel Endowed Professor in Nutrition and Health at UI. "We're curious about the role they play in the development of the breast-fed infant's gut bacteria because the bacteria found in the guts of formula-fed infants is different.”

The researchers found that a complex combination of HMO and a single HMO component could create patterns of short-chain fatty acids that would adapt as the baby got older. For the infant, the healthy microbiome could have short and long term effects. While beneficial bacteria could protect the infant from infections caused by virulent bacteria in the short term, it bolstered the immune system to address chronic health problems like asthma and food allergies in the long term.

During the experiment, scientists took breast milk from mothers of preterm babies at Chicago´s Rush University Medical Center. They then isolated the HMO and analyzed the bacteria. The researchers also examined bacteria from nine-day-old and 17-day old sow-reared and formula-reared baby pigs that were to represent three-month-old and six-month-old human infants. The scientists took the colon bacteria and placed it in test tubes that had HMO and two prebiotics that are found in baby formulas. They fermented the mixtures to see how bacterial populations would change over time and what products were created by the bacteria.

"When the HMOs were introduced, the bacteria produced short-chain fatty acids, in some cases at higher levels than other prebiotics now used in infant formula. The short-chain fatty acids can be used as a fuel source for beneficial bacteria and also affect gastrointestinal development and pH in the gut, which reduces the number of disease-causing pathogens,” explained Donovan in the statement.

The team observed that varying HMOs created distinct patterns of short fatty-chain acids and the makeup of the bacteria in the gut changed a few times.

"It was distinctly different at 9 vs. 17 days, making it likely that the functions of HMO change as the human infant gets older," continued Donovan in the statement.

The results of the project prove that HMOs are necessary in understanding the effects of breastfeeding babies.

"Several companies are now able to synthesize HMO, and in the future, we may be able to use them to improve infant formula. There's evidence that these compounds can bind to receptors on immune cells and, to our knowledge, no current prebiotic ingredient can do that," concluded Donovan in the statement.