Past research had already
indicated a link between formula-feeding and a higher risk for chronic diseases
later in life. But there were gaps in determining the basis for that link.
Carolyn Slupsky and colleagues at the University of California, set out to fill
those gaps by investigating how diet impacted metabolic changes by comparing
growth, gut microbes, and other metabolic profiles of formula fed and breast
fed infant rhesus monkeys.
The results revealed the key
differences between formula-fed and breast-fed subjects.
The researchers found that
formula-fed infants were larger than their breast-fed counterparts and had a
different gut microbe that includes higher levels of bacteria from the Ruminococcus
genus and lower levels of bacteria from the Lactobacillus
are known to be pro-inflammatory whereas Lactobacillus
bacteria are anti-inflammatory. This explained the differences in the immune
function between formula fed and breast fed infants. Breast fed ones had better
immune function which provided immediate protection against infection as
compared with their formula fed counterparts who showed elevated inflammatory
state in their first month.
They also found that despite the
higher protein content of infant formula, protein metabolism was lower in
formula fed infants, suggesting that formula fed infants have a reduced ability
to metabolize amino acids as compared with their breast fed counterparts.
Again, higher levels of uric acid
in the body combined with lower urinary pH (acidic) increase the risk for
metabolic syndrome in adults.
The researchers here noted that allantoin levels
(derivative of uric acid) were higher in infant monkeys suggesting that formula
fed infants had the higher risk of developing metabolic syndrome later in life
than the breast fed ones.
'These results demonstrate that
metabolic and gut microbiome development of formula-fed infants is different
from breast-fed infants and that the choice of infant feeding may hold future
health consequences,' said Slupsky.
The researchers also hinted that
reducing the protein content of infant formula might be beneficial in reducing
the metabolic stress in formula-fed infants.
'Our findings support the contention that infant
feeding practice profoundly influences metabolism in developing infants and may
be the link between early feeding and the development of metabolic disease
later in life,'
concluded the researchers of this study.