Soy Protein-Based Infant Formulas and Its Adverse Effects: A Systematic Review
Yasmin N.V. Amaral
J Nutrigenet Nutrigenomics 2012;5:171–302 297
Cow’s milk allergy is the most common food allergy in infants,
because they have an immature immune system and rely heavily on
antibodies in breast milk. The use of hypoallergenic formulas is considered
the alternative proposed. Currently there are three types of
formulas that can be indicated in the dietary treatment of allergy in
infants: Soy Protein based formulas, extensively hydrolyzed casein
formulas, and free amino acids based formulas.
The soy formulas have high amounts of phytate, aluminum and phytoestrogens that can
bring undesirable effects to child health.
Therefore, the objective of
this review was to describe the adverse effects of the use of soy formula
in infants. This study was a systematic review by searching the
electronic databases Pubmed and Biblioteca Virtual em Saúde, whose
sources of information to Cochrane, SciELO, LILACS and
MEDLINE. The articles were selected from the reading of the
abstracts that should provide the following information: the content
of phytoestrogens and / or aluminum in soy formula compared to
other formulas and breast milk and its possible consequences, evaluation
of growth of infants fed with soy formula and review articles
were excluded. Have been created three cards from extraction of
information from selected articles, first of all have been identified
210 articles, 19 were selected for full reading, and only 14 were
included in the review for meeting all inclusion criteria. The articles
dated from 1994 to 2012 and represented 7 countries: United States
(42.9%), Italy (14.3%), United Kingdom (14.3%), Spain (7.1%),
Finland (7.1%), Canada (7.1%) and New Zealand (7.1%). Five studies
addressed the issue of growth and development of infants fed with
soy formula, five discussed the amount of phytoestrogens in soy formula
and other four aluminum. As for weight of the infants, only one
study reported a reduction in infants fed with soy formula. Other
studies showed
extremely higher amounts of isoflavones and aluminum
in soy formula when compared to milk-based formula
or breast milk. Studies have shown the existence of high levels of isoflavones
(genistein and daidzein) and aluminum in both formulas as in infants
fed with soy formula and this fact may lead to adverse effects on
human health both during childhood and adulthood.
