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Soy protein for infant feeding: what do we know?
Purpose of review
This review discusses the safety, nutritional adequacy and
recommendations for use of soy protein formulae, based
mainly on the most relevant reports published during 2005
Concerns have recently been raised regarding potential
risks with soy protein formulae, in particular regarding their
high phytoestrogenic isoflavone content. Recent data are
insufficient to draw definitive conclusions on safety, but
authorities and paediatric societies from several countries
recently advised health professionals to use soy protein
formulae only in certain cases. Indications for use of soy
protein formulae, mainly for prevention and management of
food allergy, have also been better defined.
Soy protein formulae ensure normal growth and
development in healthy term infants but they have no
nutritional advantages over cow’s milk protein formulae.
Main indications include severe lactose intolerance,
protein formulae have no role in preventing allergy or in
management of nonspecific gastrointestinal symptoms
(e.g. infantile colic and regurgitation). They should not be
used in preterm infants or infants with food allergy
before age 6 months. After 6 months, soy protein formulae
maybe considered if tolerance tosoy protein is established.
food allergy, isoflavones, phytoestrogens, reproductive
function, soy protein formula
Curr Opin Clin Nutr Metab Care 10:360–365. ? 2007 Lippincott Williams &
Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics,
Lille University Children’s Hospital and Faculty of Medicine, Lille, France
Correspondence to Dominique Turck, Unite ´ de Gastro-ente ´rologie, He ´patologie et
Nutrition, Clinique de Pe ´diatrie, Ho ˆpital Jeanne de Flandre, 2, avenue Oscar
Lambret, 59037 Lille cedex, France
Tel: +33 3 20 44 68 85; fax: +33 3 20 44 61 34; e-mail: firstname.lastname@example.org
Current Opinion in Clinical Nutrition and Metabolic Care 2007, 10:360–
? 2007 Lippincott Williams & Wilkins
Soy formula was first used in the early 1900s and intro-
with allergy to cow’s milk protein [1,2]. Soy protein
formulae are currently given at some point during the first
and 13% in New Zealand. Use of these formulae is much
warning on potential risks associated with soy protein
formulae was recently issued, placing particular emphasis
on the high phytoestrogenic isoflavone content in such
formulae; this led authorities and paediatric societies
from several industrialized countries to advise health
professionals to use soy protein formulae only in certain
recent reports on the nutritional adequacy and safety of
soy protein formulae, and summarizes recommendations
for their use in infant feeding.
Biological value of soy protein
The biological value of soy protein is less than that of
cow’s milk protein because of its lower nitrogen conver-
sion factor and a different amino acid pattern (i.e. lower
amounts of methionine, lysine and proline, as well as
higher amounts of aspartate, glycine, arginine and
cysteine) . Methionine supplementation has been
recommended to ensure adequate nitrogen retention
and normal growth. Soy-based products have a very
low L-carnitine content, and so carnitine supplement-
ation is also necessary.
Regulations on soy protein infant and follow-
European Union must fulfill the compositional criteria
recently updated by Directive 2006/141/EC, published
on 22 December 2006 . Only protein isolates should be
used, and the minimum protein content required for
infant and follow-on soy protein formulae by European
legislation is higher than that for cow’s milk protein
formulae (2.25g/100kcal versus 1.8g/100kcal) because
of the lower bioavailability of soy protein. The main
compositional criteria specific to soy protein formulae
in Directive 2006/141/EC are summarized in Table 1.
The minimum protein content for infant formula based
on soy protein isolate has also been set at 2.25g/100kcal
in the revised standard for infant formula adopted at the
28th Session of the Codex Alimentarius Committee on
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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Soy protein for infant feeding Turck 365