Journal of Pediatrics and Neonatal Care Soy-Based Infant Formulas: A Review of Developmental and Nutritional Considerations Abstract Review Article Soy-based infant formulas are widely used as a source of nutrition for children Volume 7 Issue 3 - 2017 in the first year of life, but research is still lacking on how soy formulas affect infant nutrition and development short-term and long-term. This review article examines research spanning nearly four decades and discusses implications Biochemistry and Molecular Biology, University of Miami, USA for infant nutrition, development (with particular emphasis on the role of phytoestrogens), and other physical effects correlated to the use of soy-based *Corresponding author: Nicole Stevens, 1207 W. 20 S. infant formula. Proposals for future research are also presented. Keywords: Soy-based infant formula; Soy formula; Infant formula; Infant Pleasant Grove, UT 84062, Tel: 1-801-701-0881; Email: development Received: September 29, 2017 | Published: November 01, 2017 Abbreviations: CM: Cow’s Milk; HPLC: High Performance Discussion Liquid Chromatography; GC/MS: Gas Chromatography– Mass Spectrometry; TPO: Thyroid Peroxidase; LC/MS: Liquid Hormonal effects of soy Chromatography – Mass Spectrometry; UV-VIS: Ultraviolet-Visible Analysis methods: Traditional methods for analyzing the Introduction and mass spectrometry (GS/MS). Recently, it was found that amount of isoflavones in soy included gas chromatography Many brands of soy-based infant formulas are commercially High Performance Liquid Chromatography (HPLC) was faster, available in any supermarket. Soy-based infant formulas have demanded less technician time, less preparation time and less been in use for more than 100 years [1] and continue to be very expensive equipment [3]. Consequently, most of the studies popular as a nutritional supplement for growing infants. Recent regarding the amount of phytoestrogens in soy formulas have used HPLC. soy may contribute to a lowered risk of cardiovascular disease, Numerous studies have been done extracting phytoestrogens cancer,findings andin soy a researchlessening even of thesuggest effects that of the menopause—all phytoestrogens inof from soy formulas and comparing these amounts to the amount which could be added bonuses to consuming a soy diet early in of phytoestrogens in breast-milk collected after maternal soy life [2]. However, as researchers investigate the effects of soy consumption. Franke et al. [4] used HPLC and diode-array on infants, some concerns are arising about both the hormonal ultraviolet scanning in their study, and found that the total (phytoestrogen) and nutritional impacts that soy has on the infant physiology. Inquiries into the amount of phytoestrogens contained in soy formulas compared to cow’s milk and breast milk, how dueisoflavones to the environmental in four popular conditions soy formulas of thevaried soybean from 155growth µg/g and to these foods function differently on the infant metabolism, as well the281µg/g genetic [4]. disposition The researchers of the notedparticular that thisbreeds variation of plants. is probably Breast- as research on the effects of dosage and timing of soy feedings have produced interesting results. Yet there still remain some unanswered questions about how soy exposure in youth affects milk, they found, contains anywhere from 0.2 µMol to 1.5 µMol/L the later years of an individual. exposure[3]. The lowerfrom soy concentration formulas. of isoflavones may provide the benefits of phytoestrogens without as many of the risks of high The nutritional aspects of soy are also a concern to researchers, especially since soy is the sole source of nourishment for many infants for at least several months of their development. Studies foods.Irvine They et concluded al. [5] also that, usedif the manufacturer’sHPLC to study instructions the amount were of have been done on how the nutrition of soy formulas compares followed,isoflavones an in 0-4month-old five popular soy infant formulas would and receive six other 3mg/kg soy infantbody to breast feeding and cow-milk formulas; how infant growth and development responds to each of these feeding methods; how soy formulas may be a wise alternative to cow milk because of weight of isoflavones, and after 4 months of age supplementing food allergies; and how soy interacts with the immune system. formulasan infant’s [ Firstdiet withAlternative soy foods, Enrich may, andincrease Glucerna the isoflavone] and found intake that These studies will be presented along with the current attitudes whenby 25% following [5]. Using the GC/MS, manufacturer’s Dwyer et instructionsal. [6] analyzed of preparation,3 popular soy a and recommendations about using soy as a primary source of nutrition for growing children. single serving of infant soy formula may contain over 1000 µg of isoflavones [6]. These levels are higher than levels that have been Submit Manuscript | http://medcraveonline.com J Pediatr Neonatal Care 2017, 7(3): 00287 Copyright: Soy-Based Infant Formulas: A Review of Developmental and Nutritional Considerations ©2017 Stevens 2/6 shown to alter reproductive hormones in premenopausal women Summary: HPLC is a good method for determining the amount of have on infant development. [7], and it is not certain what effect these high levels of isoflavones servingisoflavones most in formulas soy-based provide infant a formula. dose of phytoestrogensAlthough the amount that is ofat isoflavones varies among the different soy formulas, in a regular demonstrates effects on the menstrual cycle of women. Breast There is interest not just in the amount of isoflavones in milk after the nursing mother consumes soy products. Franke least as high or much higher than the amount of isoflavones that infant formula, but also in the amount of isoflavones in breast shownmilk, while to interfere still containing in vitro with some an isoflavones, important thyroidcontains enzyme, a much a collectedet al [8]. fromtested 2 thepostpartum isoflavone women content 12 inhours human before milk consuming after the constantlower concentration diet of soy formulathan soy mayformula. modulate Since isoflavonesthyroid development have been subjects consumed 5, 10, or 20g of roasted soybeans. Milk was of an infant. Several studies have shown that infants do absorb maximumsoy, then at concentration 0, 24 and 72 hoursof only after about consuming 70 nmol/L 5, 10, [8]. or A 20g normal soy. feedingThe concentration of breast milk of atisoflavones this concentration in the breast would milk provide reached about a haveand excreteon the infantup to physiology 50% of the in theisoflavones concentrations they ingest, at which so theyit is areimportant ingested. that Long-term researchers studies focus are on necessary. the effects that isoflavones typical serving of soy formula. a thousandth the amount of isoflavones than are contained in a In Vitro Research: Nutritional Effects of Soy Human Research: Although soy formulas have been used for a catalyst essential in Divithe synthesiset al. [9] of studied thyroid thehormone effects [9]. of Theytwo decades, until recently there was a lack of rigorous studies studiedisoflavones, soybean genistein extract and using daidzein, HPLC, on UV-VIS thyroid spectrophotrometry, peroxidase (TPO), showing whether a soy diet provides for the nutritional needs and liquid chromatography / mass spectrometry (LC/MS) to of a growing infant. In a randomized controlled clinical trial, identify genistein and daidzein. Incubation of either of the protein on growing infants. At two days of age, 32 males and 32 femalesChurella wereet al. [15]randomly studied assigned the effects to aof commercialdifferent amounts soy formula of soy isoflavones (50µM of each, separately) with TPO in the presence (2.91 g protein/100 Kcal) or a soy formula containing less protein of hydrogen peroxide (200 µM) caused the enzyme to be individualsinactivated; who however, are exposed in the presenceto high levels of iodine of phytoestrogens (0.15 to 5.0 mayµM) developprevented thyroid this inactivation. problems. ThisSeveral suggests cases thatof alleged in iodine-deficient soy-related urea(2.45 nitrogen g protein/100 concentration Kcal) and in fed the that low diet protein until group. 112 days The of study age. thyroid disorders have been documented [10-12], but additional concludedThe only statistically that a commercial significant soydifference formula was provides a lower enoughplasma controlled, double-blind clinical experimentation is needed protein to meet the needs of a normal, term infant from 2 to 112 through feeding would interfere with TPO activity even in the fed infants was not compared to breast-fed or cow-milk-formula presencethat would of iodine.clarify whether continual isoflavone replenishment days of age [15]. However, in this study the growth in soy-protein- Human Research: One of the most important questions in this differences between soy isolate formula and milk-based formula, andinfants. their Jung effects et ofal. growth [16] addressed on 40 healthy, the full-termquestion newborn of nutritional white soy formulas are actually absorbed into the infant’s body. Setchell or Spanish infants until 112 days of age. They showed that body area of research is how much of the abundant isoflavones in infant differ between the two groups. Neither group showed retarded weights, lengths and head circumference did not significantly formulas:et al. [13] Nursoyused reverse-phase powdered formula, HPLC toIsomil determine powdered the isoflavoneand