Milk-Derived Amadori Products in Feces of Formula-Fed Infants

Food
processing of infant formula alters chemical structures, including
the formation of Maillard reaction products between proteins and sugars.
We detected early Maillard reaction products, so-called Amadori products,
in stool samples of formula-fed infants. In total, four Amadori products
(N-deoxylactulosyllysine, N-deoxyfructosyllysine, N-deoxylactulosylleucylisoleucine, N-deoxyfructosylleucylisoleucine)
were identified by a combination of complementary nontargeted and
targeted metabolomics approaches. Chemical structures were confirmed
by preparation and isolation of reference compounds, LC-MS/MS, and
NMR. The leucylisoleucine Amadori compounds, which most likely originate
from β-lactoglobulin, were excreted throughout the first year
of life in feces of formula-fed infants but were absent in feces of
breastfed infants. Despite high inter- and intraindividual differences
of Amadori products in the infants’ stool, solid food introduction
resulted in a continuous decrease, proving infant formula as the major
source of the excreted Amadori products.