Concerns regarding the safety of soy formula were raised after
two studies revealed that the amounts of soy isoflavone genistein,
a chemical found in commercial soy formulas, might inhibit the intestinal
growth in babies.
There is a great deal of merit surrounding this concern, particularly
because nearly 25 percent of formula-fed babies in the United States
consume soy formula.
Commercial soy formulas contain anywhere from 32 to 45 milligrams
of genistein. These concentration levels exceed the amount found
to affect menstrual cycles in women. Since formula is the only source
of nutrition for infants during their first four to six months of
life, a period in which several critical organ systems are developing,
researchers were motivated to study the possible effects of genistein.
Two Soy Studies Show Same Results -- Slowing
of Cell Reproduction
The first study involving the treatment of intestinal cells in
culture with genistein that included the same amount found in soy
formula showed that the cells ceased to grow. One researcher did
point out that the actions observed in cells in culture might not
be the same as those in infants.
The second study was made up of two groups of piglets: one group
was fed cow's milk-based formula and the other was given formula
supplemented with genistein at the amount it is found in soy formula.
It was discovered that the piglets given the genisten formula displayed
50 percent less proliferating cells in the intestine over the group
that was fed solely the cow's milk formula. Because the metabolism
and physiology of newborn pigs is so similar to human infants, researchers
believe these results could be applied to infants.
Researchers of the study cautioned that although the soy formulas
might appear to be safe based on some clinical data, these above
studies show that it might not come without side effects.
Pediatric
Research December 7, 2004. DOI: 10.1203/01.PDR.0000150723.87976.32
Science
Daily December 27, 2004
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