RESEARCHERS LINK INFANT FORMULAS TYPE TO OVERWEIGHT, DISEASES.

NEW findings from the Monell Centre reveal
that the type of formula the infant is
consuming influences weight gain of
formula-fed infants. The findings have
implications related to the infant ’s risk for
the development of obesity, diabetes and
other diseases later in life.
“Events early in life have long-term
consequences on health and one of the
most significant influences is early growth
rate, ” said study lead author, Dr.Julie
Mennella, a developmental psychobiologist
at Monell. “We already know that formula-
fed babies gain more weight than breast-
fed babies. But we did not know whether
this was true for all types of formula. ”
While most infant formulas are cow’s milk-
based, other choices include soy-based and
protein hydrolysate-based formulas. Protein
hydrolysate formulas contain pre-digested
proteins and typically are fed to infants
who cannot tolerate the intact proteins in
other formulas.
In adults, pre-digested proteins are believed
to act in the intestine to initiate the end of a
meal, thus leading to smaller meals and
intake of fewer calories. Based on this, the
authors hypothesised that infants who
were feeding protein hydrolysate formulas
would eat less and have an altered growth
pattern relative to infants feeding cow ’s
milk-based formula.
In the study, published online in the journal
Paediatrics, infants whose parents had
already decided to bottle-feed were
randomly assigned at two weeks of age to
feed either a cow ’s milk-based formula (35
infants) or a protein hydrolysate formula
(24 infants) for seven months.
Both formulas contained the same amount
of calories, but the hydrolysate formula had
more protein, including greater amounts of
small peptides and free amino acids.
Infants were weighed once each month in
the laboratory, where they also were
videotaped consuming a meal of the
assigned formula. The meal continued until
the infant signalled that s/he was full.
Over the seven months of the study, the
protein hydrolysate infants gained weight
at a slower rate than infants fed cow milk
formula. Linear growth, or length, did not
differ between the two groups,
demonstrating that the differences in
growth were specifically attributable to
weight.
“All formulas are not alike,” said Mennella.
“These two formulas have the same amount
of calories, but differ considerably in terms
of how they influence infant growth. ”
When the data were compared to national
norms for breast-fed infants, the rate of
weight gain of protein hydrolysate infants
was comparable to the breast milk
standards; in contrast, infants fed cow ’s
milk formula gained weight at a greater rate
than the same breast milk standards.
Analysis of the laboratory meal revealed the
infants fed the protein hydrolysate formula
consumed less formula during the meal.
“One of the reasons the protein hydrolysate
infants had similar growth patterns to
breast-fed infants, who are the gold
standard, is that they consumed less
formula during a feed as compared to
infants fed cow ’s milk formula” said
Mennella. “The next question to ask is: Why
do infants on cow’s milk formula
overfeed?”
The findings highlight the need to
understand the long-term influences of
infant formula composition on feeding
behaviour, growth and metabolic health.
Future studies will utilise measures of
energy metabolism and expenditure to
examine how the individual formulas
influence growth and how each differs
from breastfeeding.