Human Breast Milk
Ingredient Adjusts to Optimize for Beneficial Gut Bacteria Over Time
A new study, led by Sharon Donovan of the University of Illinois,
shows that human milk oligosaccharides, or HMO, produce short-chain fatty acids
that feed a beneficial microbial population in the infant gut.
Not only that, the bacterial composition adjusts as the baby
grows older and its needs change.
Even though HMO are a major component of human milk, present
in higher concentration than protein, many of their actions in the infant are
not well understood. HMO are virtually absent from infant formula.
For the first time, scientists have shown that a complex
mixture of HMO and a single HMO component produce patterns of short-chain fatty
acids that change as the infant gets older.
A healthy microbiome* has both short- and long-term effects
on an infant's health. In the short term, beneficial bacteria protect the
infant from infection by harmful bacteria. In the long term, beneficial
bacteria strengthen the immune system so that it can fend off chronic health
problems like food allergies and asthma.
In the study, breast milk was obtained from mothers of
preterm infants at Chicago's Rush University
Medical Center,
and the HMO were isolated and analyzed. The scientists tested bacteria from 9-
and 17-day-old sow-reared and formula-fed piglets. Because piglets grow so
rapidly, these ages reflect approximately three- and six-month-old human
infants.
The colon bacteria were added to test tubes containing HMO
and two prebiotics commonly used in infant formulas. These mixtures were
allowed to ferment and then sampled to see how the bacterial population was
changing over time and what products were being produced by the bacteria.
When the HMOs were introduced, the bacteria produced
short-chain fatty acids, at 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.
Further, different HMOs produced different patterns of
short-chain fatty acids, and the composition of bacteria in the gut changed
over time. "It was distinctly different at 9 vs. 17 days, making it likely
that the functions of HMO change as the human infant gets older," Dr. Donovan
said. "There's evidence that these compounds can bind to receptors on
immune cells and, to our knowledge, no current prebiotic ingredient can do
that," she said.
###
The above story is based on the May. 14, 2012 news release
by University of Illinois College of Agricultural, Consumer and Environmental
Sciences. The study was published in the April issue of the Journal of
Nutrition: M. Li, L. L. Bauer, X. Chen, M. Wang, T. B. Kuhlenschmidt, M. S.
Kuhlenschmidt, G. C. Fahey, S. M. Donovan. Microbial
Composition and In Vitro Fermentation Patterns of Human Milk Oligosaccharides
and Prebiotics Differ between Formula-Fed and Sow-Reared Piglets. J Nutr, 2012; 142 (4): 681 DOI:
10.3945/jn.111.154427
###
* a microbiome is the totality of microbes, their genetic
elements (genomes), and environmental interactions in a particular environment.
Useful Link
The World Alliance for Breastfeeding Action (WABA) is a
global network of individuals & organisations concerned with the protection, promotion & support of
breastfeeding worldwide. WABA action is based on the Innocenti Declaration,
the Ten Links for
Nurturing the Future and the Global
Strategy for Infant & Young Child Feeding. WABA is in consultative
status with UNICEF & an NGO in Special Consultative Status with the
Economic and Social Council of the United Nations (ECOSOC).
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