Ultrasonographic patterns of reproductive organs in infants fed soy formula: comparisons to infants fed breast milk and milk formula

A comparison of ultrasound-based testis volume with Prader orchidometry and stability of testis size relative to peers from birth to 28 weeks

BACKGROUND

Testis volume, an indicator of the reproductive development during minipuberty, is commonly measured by Prader orchidometer, despite ultrasound being the gold standard. Data are lacking on the longitudinal relationship between these two measures and on the stability of boys' relative testis size across infancy.

OBJECTIVES

To examine the relationship between ultrasound-based and orchidometer-based testis volume measurements and to assess the stability of relative testis size among individual boys in the study.

MATERIALS AND METHODS

The Infant Feeding and Early Development study is a longitudinal cohort of healthy infants recruited from hospitals in the Philadelphia area during 2010-2013. We measured testis size from birth to 28 weeks in 147 infants using Prader orchidometry (nine study visits) and ultrasound (five study visits). We modeled testis growth, extracted predicted volumes for each boy on each day of the study, and ranked these volumes from smallest to largest.

RESULTS

The average testis volume trajectory exhibited linear growth over the first 16 weeks followed by slower growth and then a plateau. Prader orchidometry overestimated testis size by almost 3-fold, compared to ultrasound. A range of ultrasound volumes corresponded to each bead size (e.g., bead size of 1 cm3 corresponded to an ultrasound-based volume between 0.11 and 0.87 cm3). Infants changed rankings of median of 22 positions (of 147) across the entire 6-month follow-up. Infants' ranks near birth were highly correlated with their ranks at the end of the study.

DISCUSSION

Consistent with other studies, we found wide variability in testis size during infancy and that Prader orchidometry overestimates testis size. When compared to ultrasound, orchidometry only crudely estimates testis size in this age group. Ultrasound-based volumes generally showed stability in relative testis size across infancy.

CONCLUSION

Accurate measurement of testis size is difficult using orchidometry in infants. This highlights the need for ultrasound for accurate measurement, with a one-time measurement likely sufficient to determine relative testis size across the first 6 months of infancy.

Cohort profile: The Copenhagen Analgesic Study-The COPANA cohort

BACKGROUND

Development of the gonads during fetal life is complex and vital for adult reproductive health. Cell and animal studies have shown an alarming effect of mild analgesics on germ cells in both males and females. More than 50% of pregnant women use mild analgesics during pregnancy, which potentially could compromise the reproductive health of the next generation.

OBJECTIVES

We present a research protocol designed to evaluate the effect of prenatal exposure to mild analgesics and endocrine-disrupting chemicals on gonadal function in the offspring.

POPULATION

Healthy, singleton pregnant women and their partners.

DESIGN

The COPANA cohort is a prospective, observational pregnancy and birth cohort.

METHODS

Participants were enrolled during the first trimester of pregnancy. Information on the use of mild analgesics was collected retrospectively 3 months prior to pregnancy and prospectively every 2 weeks throughout the study. We collected extensive data on lifestyle and reproductive health. Biospecimens were collected in the first trimester (maternal and paternal urine- and blood samples), in the third trimester in conjunction with a study-specific ultrasound scan (maternal urine sample), and approximately 3 months post-partum during the infant minipuberty period (maternal and infant urine- and blood samples). A comprehensive evaluation of reproductive function in the infants during the minipuberty phase was performed, including an ultrasound scan of the testis or ovaries and uterus.

PRELIMINARY RESULTS

In total, 685 pregnant women and their partners were included between March 2020 and January 2022. A total of 589 infants (287 males) and their parents completed the follow-up during the minipuberty phase (December 2020-November 2022).

CONCLUSIONS

The Copenhagen Analgesic Study holds the potential to provide novel and comprehensive insights into the impact of early and late prenatal exposure to mild analgesics and other endocrine-disrupting chemicals on future reproductive function in the offspring.

Associations of Exposure to Air Pollution during the Male Programming Window and Mini-Puberty with Anogenital Distance and Penile Width at Birth and at 1 Year of Age in the Multicenter U.S. TIDES Cohort

BACKGROUND

Ambient air pollution may be a developmental endocrine disruptor. In animal models, gestational and perinatal exposure to diesel exhaust and concentrated particulate matter alters anogenital distance (AGD), a marker of prenatal androgen activity, in both sexes. Little is known in humans.

OBJECTIVES

We examined exposure to fine particulate matter (PM 2.5 ) and nitrogen dioxide (NO 2 ) in relation to human AGD at birth and at 1 year of age, focusing on exposures during critical windows of reproductive development: the male programming window (MPW; gestational weeks 8-14) and mini-puberty (postnatal months 1-3).

METHODS

The Infant Development and Environment Study (TIDES) recruited first trimester pregnant women (n = 687 ) at four U.S. sites (Minneapolis, Minnesota; Rochester, New York; San Francisco, California; and Seattle, Washington) from 2010 to 2012. We measured anus to clitoris (AGD-AC) and anus to fourchette (AGD-AF) in female infants at birth; in males, we measured anus to penis (AGD-AP), anus to scrotum (AGD-AS), and penile width at birth and at 1 year of age. Using advanced spatiotemporal models, we estimated maternal exposure to PM 2.5 and NO 2 in the MPW and mini-puberty. Covariate-adjusted, sex-stratified linear regression models examined associations between PM 2.5 and NO 2 and AGD.

RESULTS

In males, a 1 - μ g / m 3 increase in PM 2.5 exposure during the MPW was associated with shorter AGD at birth, but a longer AGD at 1 year of age (e.g., birth AGD-AP: β = - 0.35 mm ; 95% CI: - 0.62 , - 0.07 ; AGD-AS: β = 0.37 mm ; 95% CI: 0.02, 0.73). Mini-pubertal PM 2.5 exposure was also associated with shorter male AGD-AP (β = - 0.50 mm ; 95% CI: - 0.89 , - 0.11 ) at 1 year of age. Although not associated with male AGD measures, 1 -ppb increases in NO 2 exposure during the MPW (β = - 0.07 mm ; 95% CI: - 0.02 , - 0.12 ) and mini-puberty (β = - 0.04 mm ; 95% CI: - 0.08 , 0.01) were both associated with smaller penile width at 1 year of age. Results were similar in multipollutant models, where we also observed that in females AGD-AC was inversely associated with PM 2.5 exposure, but positively associated with NO 2 exposure.

DISCUSSION

PM 2.5 and NO 2 exposures during critical pre- and postnatal windows may disrupt reproductive development. More work is needed to confirm these novel results and clarify mechanisms. https://doi.org/10.1289/EHP12627.

Oestrogens and progesterone in human milk and their effects on infant health outcomes: A narrative review

Human milk (HM) is a complex biological system that contains a wide range of bioactive components including oestrogens and progesterone. Whilst maternal oestrogens and progesterone concentrations drop rapidly after birth, they remain detectable in HM across lactation. Phytoestrogens and mycoestrogens, which are produced by plants and fungi, are also present in HM and can interact with oestrogen receptors to interfere with normal hormone functions. Despite the potential impact of HM oestrogens and progesterone on the infant, limited research has addressed their impact on the growth and health of breastfed infants. Furthermore, it is important to comprehensively understand the factors that contribute to these hormone levels in HM, in order to establish effective intervention strategies. In this review, we have summarized the concentrations of naturally occurring oestrogens and progesterone in HM from both endogenous and exogenous sources and discussed both maternal factors impacting HM levels and relationships with infant growth.

A Longitudinal Observational Study of Skeletal Development Between Ages 3 Months and 6 Years in Children Fed Human Milk, Milk Formula or Soy Formula

BACKGROUND

Early infant feeding can impact skeletal development. Most children are fed breast milk (BF), dairy based infant formula (MF), or soy based infant formula (SF) during the first year of life. The National Health and Nutrition Examination Survey 2003-2010 reports that 12% of U.S. infants consume soy-based infant formula. Despite potential effects of soy-associated isoflavones on skeletal development, studies investigating bone metabolism and structural and functional bone indices in children are lacking.

OBJECTIVE

The aim of this observational study was to investigate early effects of SF intake on bone metabolism and structure during the first 6 years of life by comparing infants fed BF, MF, or SF.

DESIGN

A total of 433 healthy infants were followed from 3 months to 6 years of age. Children's skeletal development was assessed using dual-energy X-ray absorptiometry (DXA, N=433) and peripheral quantitative computed tomography (pQCT, N=78). Urinary biomarkers of bone metabolism (N-terminal telopeptide of type I collagen [NTx] and osteocalcin) were evaluated by immunoassays at 6, 24, 60 and 72 months.

RESULTS

No statistically significant group differences were observed in BMD between children who were BF, MF or SF using DXA or pQCT. At 6 years of age, children who consumed SF in infancy had significantly greater whole- body BMC measured by DXA compared to the MF group. Six-month-old SF boys had significantly greater levels of NTx compared to MF boys, as well as significantly greater osteocalcin levels compared to BF boys.

CONCLUSIONS

Together, these data suggest that while SF infants at age 6 months may have some enhanced bone metabolism compared to BF and MF infants, as indicated by the urinary biomarkers, no differences in bone metabolism or BMD were noted between ages 2 and 6 years.

CLINICAL TRIAL REGISTRY NUMBER

NCT00616395; https://clinicaltrials.gov/ct2/show/NCT00616395.

Phytoestrogens and Health Effects

Phytoestrogens are literally estrogenic substances of plant origin. Although these substances are useful for plants in many aspects, their estrogenic properties are essentially relevant to their predators. As such, phytoestrogens can be considered to be substances potentially dedicated to plant-predator interaction. Therefore, it is not surprising to note that the word phytoestrogen comes from the early discovery of estrogenic effects in grazing animals and humans. Here, several compounds whose activities have been discovered at nutritional concentrations in animals and humans are examined. The substances analyzed belong to several chemical families, i.e., the flavanones, the coumestans, the resorcylic acid lactones, the isoflavones, and the enterolignans. Following their definition and the evocation of their role in plants, their metabolic transformations and bioavailabilities are discussed. A point is then made regarding their health effects, which can either be beneficial or adverse depending on the subject studied, the sex, the age, and the physiological status. Toxicological information is given based on official data. The effects are first presented in humans. Animal models are evoked when no data are available in humans. The effects are presented with a constant reference to doses and plausible exposure.

Soy Formula Is Not Estrogenic and Does Not Result in Reproductive Toxicity in Male Piglets: Results from a Controlled Feeding Study

Soy infant formula which is fed to over half a million infants per year contains isoflavones such as genistein, which have been shown to be estrogenic at high concentrations. The developing testis is sensitive to estrogens, raising concern that the use of soy formulas may result in male reproductive toxicity. In the current study, male White-Dutch Landrace piglets received either sow milk (Sow), or were provided milk formula (Milk), soy formula (Soy), milk formula supplemented with 17-beta-estradiol (2 mg/kg/d) (M + E2) or supplemented with genistein (84 mg/L of diet; (M + G) from postnatal day 2 until day 21. E2 treatment reduced testis weight (p < 0.05) as percentage of body weight, significantly suppressed serum androgen concentrations, increased tubule area, Germ cell and Sertoli cell numbers (p < 0.05) relative to those of Sow or Milk groups. Soy formula had no such effects relative to Sow or Milk groups. mRNAseq revealed 103 differentially expressed genes in the M + E2 group compared to the Milk group related to endocrine/metabolic disorders. However, little overlap was observed between the other treatment groups. These data suggest soy formula is not estrogenic in the male neonatal piglet and that soy formula does not significantly alter male reproductive development.

Developmental exposure to phytoestrogens found in soy: New findings and clinical implications

Exposure to naturally derived estrogen receptor activators, such as the phytoestrogen genistein, can occur at physiologically relevant concentrations in the human diet. Soy-based infant formulas are of particular concern because infants consuming these products have serum genistein levels almost 20 times greater than those seen in vegetarian adults. Comparable exposures in animal studies have adverse physiologic effects. The timing of exposure is particularly concerning because infants undergo a steroid hormone-sensitive period termed "minipuberty" during which estrogenic chemical exposure may alter normal reproductive tissue patterning and function. The delay between genistein exposure and reproductive outcomes poses a unique challenge to collecting epidemiological data. In 2010, the U.S. National Toxicology Program monograph on the safety of the use of soy formula stated that the use of soy-based infant formula posed minimal concern and emphasized a lack of data from human subjects. Since then, several new human and animal studies have advanced our epidemiological and mechanistic understanding of the risks and benefits of phytoestrogen exposure. Here we aim to identify clinically relevant findings regarding phytoestrogen exposure and female reproductive outcomes from the past 10 years, with a focus on the phytoestrogen genistein, and explore the implications of these findings for soy infant formula recommendations. Research presented in this review will inform clinical practice and dietary recommendations for infants based on evidence from both clinical epidemiology and basic research advances in endocrinology and developmental biology from mechanistic in vitro and animal studies.

Phytoestrogens (Resveratrol and Equol) for Estrogen-Deficient Skin-Controversies/Misinformation versus Anti-Aging In Vitro and Clinical Evidence via Nutraceutical-Cosmetics

The overarching theme for this review is perspective. Superfoods (a marketing term for fruits and vegetables, etc.) have a positive connotation, while many superfoods contain phytoestrogens, a term that is alarming to the public and has a negative connotation because phytoestrogens are endocrine-disruptors, even though they are strong antioxidants that have many health benefits. To understand phytoestrogens, this paper provides a brief summary of the characteristics of: (a) estrogens, (b) estrogen receptors (ER), (c) estrogen-deficient skin, (d) how perspective(s) get off track, (e) phytoestrogen food sources, and (f) misconceptions of phytoestrogens and food safety, in general, that influence person(s) away from what is true. Finally, a brief history of cosmetics to nutraceuticals is covered plus the characteristics of phytoestrogens, resveratrol and equol on: (g) estrogen receptor binding, (h) topical and oral dosing, and (i) in vitro, molecular mechanisms and select clinical evidence, where both phytoestrogens (resveratrol and equol) demonstrate promising applications to improve skin health is presented along with future directions of nutraceuticals. Perspective is paramount in understanding the controversies associated with superfoods, phytoestrogens, and endocrine-disruptors because they have both positive and negative connotations. Everyone is exposed to and consumes these molecules everyday regardless of age, gender, or geographic location around the world, and how we understand this is a matter of perspective.

Neurodevelopmental Outcomes in Infants Fed with Soy Formula: A Retrospective, National Population-Based Observational Cohort Study

BACKGROUND

Soy-based infant formulas are increasingly popular, but data regarding their effects on neurodevelopmental outcomes during early childhood is scanty.

OBJECTIVE

This study investigated the effect of consuming soy-based infant formula at 9-12 mo after birth on the subsequent development of epilepsy, neurodevelopmental disorders, and developmental status.

METHODS

This nationwide retrospective administrative study used health screening examinations and linked insurance claims data of children born in Korea during 2008 and 2009. Infants who received soy formula were compared with those who received cow's milk formula using propensity score matching that considered birth history, economic status, clinical conditions, and drug prescription records. Exposure was defined as soy formula feeding determined from questionnaires completed by the parents when children were 9-12 mo old. Outcomes were epilepsy, attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and developmental status. Children were followed until 31 December, 2017.

RESULTS

A total of 153,841 eligible participants were enrolled; 11,535 (7.5%) children received soy formula, while 142,864 (92.5%) received cow's milk formula. The incidence rate of epilepsy during the follow-up period was 29.8 per 100,000 person-years (95% CI: 19.48, 41.65) in the soy formula group and 22.6 per 100,000 person-years (95% CI: 31.97, 59.07) in the cow's milk formula group, with no significant difference (aHR: 1.318; 95% CI: 0.825, 2.106). The 2 groups also had no difference based on prespecified analysis using different definitions of epilepsy. Likewise, no significant associations of soy formula with ADHD (aHR: 1.26; 95% CI: 1.00, 1.60) or ASD (aHR: 0.99; 95% CI: 0.54, 1.83), or delays of developmental stages were observed.

CONCLUSIONS

Feeding with soy formula rather than cow's milk formula had no apparent association with increased risks of epilepsy, ADHD, ASD, and developmental status, according to this cohort composed of a general pediatric population.

Reproductive Hormone Concentrations and Associated Anatomical Responses: Does Soy Formula Affect Minipuberty in Boys?

CONTEXT

Soy formula feeding is common in infancy and is a source of high exposure to phytoestrogens, documented to influence vaginal cytology in female infants. Its influence on minipuberty in males has not been established.

OBJECTIVE

To assess the association between infant feeding practice and longitudinally measured reproductive hormones and hormone-responsive tissues in infant boys.

METHODS

The Infant Feeding and Early Development study was a prospective cohort of maternal-infant dyads requiring exclusive soy formula, cow milk formula, or breast milk feeding during study follow-up. In the 147 infant boy participants, serum testosterone, luteinizing hormone, stretched penile length, anogenital distance, and testis volume were longitudinally assessed from birth to 28 weeks. We examined feeding-group differences in age trajectories for these outcomes using mixed-effects regression splines.

RESULTS

Median serum testosterone was at pubertal levels at 2 weeks (176 ng/dL [quartiles: 124, 232]) and remained in this range until 12 weeks in all feeding groups. We did not observe differences in trajectories of hormone concentrations or anatomical measures between boys fed soy formula (n = 55) and boys fed cow milk formula (n = 54). Compared with breastfed boys (n = 38), soy formula-fed boys had a more rapid increase in penile length (P = .004) and slower initial lengthening of anogenital distance (P = .03), but no differences in hormone trajectories.

CONCLUSION

Reproductive hormone concentrations and anatomical responses followed similar trajectories in soy and cow milk formula-fed infant boys. Our findings suggest that these measures of early male reproductive development do not respond to phytoestrogen exposure during infancy.

Characterization of ovarian development in girls from birth to 9 months

BACKGROUND

The minipuberty of infancy is a period of increased reproductive axis activity. Changes in reproductive hormone concentrations and organ size occur during this period, but longitudinal changes have not been well described.

OBJECTIVES

The objective of this study was to characterize ovarian growth trajectories and ovarian follicle development during the first 9 months of life in a large longitudinal cohort of healthy girls.

METHODS

Data from the Infant Feeding and Early Development Study, a longitudinal cohort study of oestrogen-responsive outcomes in healthy infants, were used to estimate ovarian growth trajectories and describe the presence of ovarian antral follicles in girls 0-9 months old. Ovarian ultrasound evaluations were performed on the infants within 72 hours of birth (newborn visit) and at 4, 8, 16, 24, and 32 weeks of age. Mixed-effects regression splines were used to characterize changes in ovarian volume during infancy and assess the association between the presence of ovarian follicles at the newborn visit and ovarian growth.

RESULTS

This analysis included 163 girls with two or more ovarian ultrasounds in the study. Results from the estimated overall ovarian growth trajectory show that ovarian volume increases more than sixfold during the first 16 weeks after birth and then remains relatively stable in the later weeks of infancy. Among girls with observable ovaries at the newborn visit (n = 133), girls with at least one visible ovarian follicle showed more rapid initial ovarian growth compared with girls without visible follicles.

CONCLUSIONS

Infant ovarian volume increased to a peak at 16 weeks, which was influenced by the number and size of developing follicles. This research contributes to future development of reference ranges for postnatal ovarian growth in healthy, term infants.

Developmental assessments during the first 5 years of life in infants fed breast milk, cow's milk formula, or soy formula

OBJECTIVE

To investigate the effects of infant feeding mode on childhood cognition and language as the differential effects of infant feeding on development remain understudied.

METHODS

Breastfed [BF, 174], cow's milk-based formula-fed [MF, 169], or soy protein-based formula-fed [SF, 161] children were longitudinally tested from age 3 to 60 months for neurodevelopment. Data were analyzed using mixed models while adjusting for multiple covariates. Sex differences were also assessed.

RESULTS

Standard scores were within established norms for all groups. There were no differences in mental development to age 24 months, yet BF children had significantly higher motor development scores at age 3 months than SF children (99.1 versus. 97.2). BF children had significantly higher composite intelligence scores at 48 months than MF and SF children (113.4 versus. 109.6 and 108.4, respectively) and higher verbal intelligence scores than SF children at 48 (105.6 versus. 100.7) and 60 months (109.8 versus. 105.9). Greater total language scores at ages 36 and 48 months were found in BF children compared with children fed MF or SF (p < .001), with differences between sexes for auditory comprehension. Higher total language scores at age 60 months were found between BF and SF (105.0 versus. 100.1).

CONCLUSION

Breastfeeding was associated with small, statistically significant, differences between children ages 3 and 5 years in verbal intelligence, expressive communication, and auditory comprehension with the latter having potential sexual dimorphic effects. Yet, these differences remain small and may not be of clinical relevance. Overall, MF and SF did not significantly differ.

Infant Formula Feeding Changes the Proliferative Status in Piglet Neonatal Mammary Glands Independently of Estrogen Signaling

BACKGROUND

Soy infant formula contains isoflavones, which are able to bind to and activate estrogen receptor (ER) pathways. The mammary gland is sensitive to estrogens, raising concern that the use of soy formulas may promote premature development.

OBJECTIVE

We aimed to determine if soy formula feeding increases mammary gland proliferation and differentiation in comparison to other infant postnatal diets.

METHODS

White-Dutch Landrace piglets aged 2 d received either sow milk (Sow), or were provided milk formula (Milk), soy formula (Soy), milk formula supplemented with 17-beta-estradiol (2 mg/(kg·d); M + E2), or milk formula supplemented with genistein (84 mg/L of diet; M + G) until day 21. Mammary gland proliferation and differentiation was assessed by histology, and real-time RT-PCR confirmation of differentially expressed genes identified by microarray analysis.

RESULTS

Mammary terminal end bud numbers were 19-31% greater in the Milk, Soy, and M + G groups relative to the Sow and M + E2, P <0.05. Microarray analysis identified differentially expressed genes between each formula-fed group relative to the Sow (±1.7-fold, P <0.05). Real-time RT-PCR confirmed 2- to 4-fold increases in mRNA transcripts of genes involved in cell proliferation, insulin-like growth factor 1 (IGF1), fibroblast growth factor 10 (FGF10), and fibroblast growth factor 18 (FGF18), in all groups relative to the Sow, P <0.05. In contrast, genes involved in cell differentiation and ductal morphogenesis, angiotensin II receptor type 2 (AGTR2), microtubule associated protein 1b (MAP1B), and kinesin family member 26b (KIF26B), were significantly upregulated by 2-, 4-, and 13-fold, respectively, in the M + E2 group. Additionally, mRNA expression of ER-specific gene targets, progesterone receptor (PGR), was increased by 12-fold, and amphiregulin (AREG) and Ras-like estrogen regulated growth inhibitor (RERG) expression by 1.5-fold in the M + E2 group, P <0.05. In the soy and M + G groups, mRNA expressions of fatty acid synthesis genes were increased 2- to 4-fold.

CONCLUSIONS

Our data indicate soy formula feeding does not promote ER-signaling in the piglet mammary gland. Infant formula feeding (milk- or soy-based) may initiate proliferative pathways independently of estrogenic signaling.

Isoflavones

Phytoestrogens are naturally occurring nonsteroidal phenolic plant compounds that, due to their molecular structure and size, resemble vertebrate steroids estrogens. This review is focused on plant flavonoids isoflavones, which are ranked among the most estrogenic compounds. The main dietary sources of isoflavones for humans are soybean and soybean products, which contain mainly daidzein and genistein. When they are consumed, they exert estrogenic and/or antiestrogenic effects. Isoflavones are considered chemoprotective and can be used as an alternative therapy for a wide range of hormonal disorders, including several cancer types, namely breast cancer and prostate cancer, cardiovascular diseases, osteoporosis, or menopausal symptoms. On the other hand, isoflavones may also be considered endocrine disruptors with possible negative influences on the state of health in a certain part of the population or on the environment. This review deals with isoflavone classification, structure, and occurrence, with their metabolism, biological, and health effects in humans and animals, and with their utilization and potential risks.

EB 2017 Article: Soy protein isolate feeding does not result in reproductive toxicity in the pre-pubertal rat testis

The isoflavone phytoestrogens found in the soy protein isolate used in soy infant formulas have been shown to have estrogenic actions in the developing male reproductive tract resulting in reproductive toxicity. However, few studies have examined potential estrogenicity of soy protein isolate as opposed to that of pure isoflavones. In this study, we fed weanling male Sprague-Dawley rats a semi-purified diet with casein or soy protein isolate as the sole protein source from postnatal day 21 to 33. Additional groups were fed casein or soy protein isolate and treated s.c. with 10 µg/kg/d estradiol via osmotic minipump. Estradiol treatment reduced testis, prostate weights, and serum androgen concentrations ( P < 0.05). Soy protein isolate had no effect. Estradiol up-regulated 489 and down-regulated 1237 testicular genes >1.5-fold ( P < 0.05). In contrast, soy protein isolate only significantly up-regulated expression of 162 genes and down-regulated 16 genes. The top 30 soy protein isolate-up-regulated genes shared 93% concordance with estradiol up-regulated genes. There was little overlap between soy protein isolate down-regulated genes and those down-regulated by estradiol treatment. Functional annotation analysis revealed significant differences in testicular biological processes affected by estradiol or soy protein isolate. Estradiol had major actions on genes involved in reproductive processes including down-regulation of testicular steroid synthesis and expression of steroid receptor activated receptor (Star) and cytochrome P450 17α-hydroxylase/(Cyp17a1). In contrast, soy protein isolate primarily affected pathways associated with macromolecule modifications including ubiquitination and histone methylation. Our results indicate that rather than acting as a weak estrogen in the developing testis, soy protein isolate appears to act as a selective estrogen receptor modulator with little effect on reproductive processes. Impact statement Soy protein isolate (SPI) is the sole protein used to make soy-based infant formulas. SPI contains phytoestrogens, which are structurally similar to estradiol. These phytoestrogens, daidzein, genistein, and equol, fit the definition of endocrine-disrupting compounds, and at high concentrations, have estrogenic actions resulting in reproductive toxicity in the developing male, when provided as isolated chemicals. However, few animal studies have examined the potential estrogenicity of SPI as opposed to pure isoflavones. In this study, SPI feeding did not elicit an estrogenic response in the testis nor any adverse outcomes including reduced testicular growth, or androgen production during early development in rats when compared to those receiving estradiol. These findings are consistent with emerging data showing no differences in reproductive development in males and female children that received breast milk, cow's milk formula, or soy infant formula during the postnatal feeding period.

Soy-Based Infant Formula: Are Phyto-Oestrogens Still in Doubt?

Although Scientific Societies have stated that there are very few indications for the use of soy-based formula (SF) in infant nutrition, their utilization rates have been repeatedly found to be higher than expected. It is likely that a significant role in this regard is played by the belief that the use of SF during infancy can reduce the risk of the development of several diseases later in life. Although no definitive data that can substantiate these claims have been collected, many people perceive soy consumption to confer significant health benefits and might also use soy for infant nutrition. However, not all the problems regarding safety of SF in infants have been definitively solved. Among risks, the potentially toxic role of the phyto-oestrogens contained in SF is not definitively established. In vitro and animal studies have raised suspicions that SF could have potentially negative effects on sexual development and reproductive function, neurobehavioral development, immune function, and thyroid function. Several studies in humans have aimed to assess whether the results of animal studies can be applied to humans and whether SF can be used in infants following the official recommendations. The results are somewhat conflicting. The aim of this narrative review is to discuss what is presently known regarding the impact of phyto-oestrogens in SF on early and late child development. PubMed was used to search for the studies published from January 1980 to June 2017 using the keywords: “soy,” “soy formula,” “child,” “phytoestrogens.” Analysis of the literature showed that a global evaluation of the impact of modern SFs on human development seems to suggest that their use is not associated with relevant abnormalities. Only children with congenital hypothyroidism need adequate monitoring of thyroid function.

A Longitudinal Study of Estrogen-Responsive Tissues and Hormone Concentrations in Infants Fed Soy Formula

PURPOSE

Chemicals with hormonelike activity, such as estrogenic isoflavones, may perturb human development. Infants exclusively fed soy-based formula are highly exposed to isoflavones, but their physiologic responses remain uncharacterized. Estrogen-responsive postnatal development was compared in infants exclusively fed soy formula, cow-milk formula, and breast milk.

METHODS

We enrolled 410 infants born in Philadelphia-area hospitals between 2010 and 2014; 283 were exclusively fed soy formula (n = 102), cow-milk formula (n = 111), or breast milk (n = 70) throughout the study (birth to 28 or 36 weeks for boys and girls, respectively). We repeatedly measured maturation index (MI) in vaginal and urethral epithelial cells using standard cytological methods, uterine volume and breast-bud diameter using ultrasound, and serum estradiol and follicle-stimulating hormone levels. We estimated MI, organ-growth, and hormone trajectories by diet using mixed-effects regression splines.

RESULTS

Maternal demographics did not differ between cow-milk-fed and soy-fed infants but did differ between formula-fed and breastfed infants. Vaginal-cell MI trended higher (P = 0.01) and uterine volume decreased more slowly (P = 0.01) in soy-fed girls compared with cow-milk-fed girls; however, their trajectories of breast-bud diameter and hormone concentrations did not differ. We observed no significant differences between boys fed cow-milk vs soy formula; estradiol was not detectable. Breastfed infants differed from soy-formula-fed infants in vaginal-cell MI, uterine volume, and girls' estradiol and boys' breast-bud diameter trajectories.

CONCLUSIONS

Relative to girls fed cow-milk formula, those fed soy formula demonstrated tissue- and organ-level developmental trajectories consistent with response to exogenous estrogen exposure. Studies are needed to further evaluate the effects of soy on child development.

Adverse Effects of Nutraceuticals and Dietary Supplements

Over 70% of Americans take some form of dietary supplement every day, and the supplement industry is currently big business, with a gross of over $28 billion. However, unlike either foods or drugs, supplements do not need to be registered or approved by the US Food and Drug Administration (FDA) prior to production or sales. Under the Dietary Supplement Health and Education Act of 1994, the FDA is restricted to adverse report monitoring postmarketing. Despite widespread consumption, there is limited evidence of health benefits related to nutraceutical or supplement use in well-nourished adults. In contrast, a small number of these products have the potential to produce significant toxicity. In addition, patients often do not disclose supplement use to their physicians. Therefore, the risk of adverse drug-supplement interactions is significant. An overview of the major supplement and nutraceutical classes is presented here, together with known toxic effects and the potential for drug interactions.

Sex Hormones, Gonadotropins, and Sex Hormone-binding Globulin in Infants Fed Breast Milk, Cow Milk Formula, or Soy Formula

Measurement of endogenous hormones in early life is important to investigate the effects of hormonally active environmental compounds. To assess the possible hormonal effects of different feeding regimens in different sample matrices of infants, 166 infants were enrolled from two U.S hospitals between 2006 and 2009. The children were classified into exclusive soy formula, cow milk formula or breast milk regimens. Urine, saliva and blood samples were collected over the first 12 months of life. Estradiol, estrone, testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and sex hormone-binding globulin (SHBG) levels were measured in the three matrices. Lower estradiol and LH levels were found in urine and saliva samples of soy formula-fed boys compared to cow formula-fed boys. Higher LH level was found in urine samples of soy formula-fed girls compared to cow formula-fed girls. However, we found neither a neonatal testosterone rise in the boys nor a gender-specific difference in testosterone levels, which suggests that urinary testosterone levels may not accurately reflect blood levels during mini-puberty. Nevertheless, our study shows that blood, urine and saliva samples are readily collectible and suitable for multi-hormone analyses in children and allow examination of hypotheses concerning endocrine effects from dietary compounds.

Size of testes, ovaries, uterus and breast buds by ultrasound in healthy full-term neonates ages 0-3 days

BACKGROUND

Hormonally sensitive organs in the neonate can change size within days of birth as circulating maternal estrogen wanes. Although several reports document the size of these organs through infancy, few focus attention on the near-birth period. Clinical and research evaluation of hormonal and genitourinary disorders would benefit from reference size standards.

OBJECTIVE

We describe the size of the uterus, ovaries, testes and breast buds in healthy term neonates.

MATERIALS AND METHODS

As part of the Infant Feeding and Early Development (IFED) study, we sonographically measured the largest diameter of these organs in sagittal, transverse and anterior-posterior planes for 194 female and 204 male newborns up to 3 days old. We calculated mean, median and percentiles for longest axis length and for volume calculated from measured diameters. We evaluated size differences by laterality, gender and race and compared our observations against published values.

RESULTS

Mean length and mean volume were as follows: uterus, 4.2 cm and 10.0 cm³; ovary, 1.0 cm and 0.2 cm³; testis, 1.1 cm and 0.3 cm³ (0.4 cm³ Lambert volume); female breast bud, 1.2 cm and 0.7 cm³; male breast bud, 1.1 cm and 0.6 cm³. Breast buds were larger in females than males. Laterality differences were typically below the precision of clinical measurement. No significant race differences were detected.

CONCLUSION

Using data from our large cohort together with published values, we provide guidelines for evaluating the size of reproductive organs within the first 3 days of age. Discrepancies between our results and published values are likely attributable to technique.

Skin aging and oxidative stress: Equol's anti-aging effects via biochemical and molecular mechanisms

Oxygen in biology is essential for life. It comes at a cost during normal cellular function, where reactive oxygen species (ROS) are generated by oxidative metabolism. Human skin exposed to solar ultra-violet radiation (UVR) dramatically increases ROS production/oxidative stress. It is important to understand the characteristics of human skin and how chronological (intrinsic) aging and photo-aging (extrinsic aging) occur via the impact of ROS production by cascade signaling pathways. The goal is to oppose or neutralize ROS insults to maintain good dermal health. Botanicals, as active ingredients, represent one of the largest categories used in dermatology and cosmeceuticals to combat skin aging. An emerging botanical is equol, a polyphenolic/isoflavonoid molecule found in plants and food products and via gastrointestinal metabolism from precursor compounds. Introductory sections cover oxygen, free radicals (ROS), oxidative stress, antioxidants, human skin aging, cellular/molecular ROS events in skin, steroid enzymes/receptors/hormonal actions and genetic factors in aging skin. The main focus of this review covers the characteristics of equol (phytoestrogenic, antioxidant and enhancement of extracellular matrix properties) to reduce skin aging along with its anti-aging skin influences via reducing oxidative stress cascade events by a variety of biochemical/molecular actions and mechanisms to enhance human dermal health.

Removing isoflavones from modern soyfood: Why and how?

Estrogenic isoflavones were found, in the 1940s, to disrupt ewe reproduction and were identified in soy-consumers' urine in 1982. This led to controversy about their safety, often supported by current Asian diet measurements, but not by historical data. Traditional Asian recipes of soy were tested while assaying soy glycosilated isoflavones. As these compounds are water-soluble, their concentration is reduced by soaking. Pre-cooking or simmering time-dependently reduces the isoflavone:protein ratio in Tofu. Cooking soy-juice for 15 or 60min decreases the isoflavone:protein ratios in Tofu from 6.90 to 3.57 and 1.80, respectively (p<0.001). Traditional Tempeh contains only 18.07% of the original soybean isoflavones (p<0.001). Soy-juice isoflavones were reduced by ultra-filtration (6.54 vs 1.24 isoflavone:protein; p<0.001). Soy-protein and isoflavones are dissociated by water rinsing and prolonged cooking, but these have no equivalent in modern processes. As regards human health, a precise definition of the safety level of isoflavone intake requires additional studies.

Risks and benefits of phytoestrogens: where are we now?

PURPOSE OF REVIEW

The estrogenic effects of genistein, as reconfirmed by the American National Toxicology Program (USA-NTP), have led to several new clinical studies being undertaken. Here, we highlight the most relevant recent data, reporting either beneficial or adverse effects.

RECENT FINDINGS

Phytoestrogens are natural molecules from edible plants exhibiting estrogenic activities. Post-USA-NTP studies investigated both human and animal reproductive and other physiological issues. These studies showed that estrogens can be either deleterious for reproduction and estrogen-dependent diseases, or beneficial for those with steroid deficiencies, that is more than 50. The specific outcome depends on exposure level and on the estrogenic status of the patients exposed. Recently, it was reported that, with the industrialization of soybean process, phytoestrogen exposure dramatically increased in both humans and cattle, whereas traditional Asian soy-food-processing empirically removed isoflavones. Phytoestrogen exposure has also become more widespread with the progressive internationalization of soybean use in human and cattle food.

SUMMARY

Phytoestrogens should be considered as modern endocrine disruptors and studied as such.

Environmental factors, epigenetics, and developmental origin of reproductive disorders

Sex-specific differentiation, development, and function of the reproductive system are largely dependent on steroid hormones. For this reason, developmental exposure to estrogenic and anti-androgenic endocrine disrupting chemicals (EDCs) is associated with reproductive dysfunction in adulthood. Human data in support of "Developmental Origins of Health and Disease" (DOHaD) comes from multigenerational studies on offspring of diethylstilbestrol-exposed mothers/grandmothers. Animal data indicate that ovarian reserve, female cycling, adult uterine abnormalities, sperm quality, prostate disease, and mating behavior are susceptible to DOHaD effects induced by EDCs such as bisphenol A, genistein, diethylstilbestrol, p,p'-dichlorodiphenyl-dichloroethylene, phthalates, and polyaromatic hydrocarbons. Mechanisms underlying these EDC effects include direct mimicry of sex steroids or morphogens and interference with epigenomic sculpting during cell and tissue differentiation. Exposure to EDCs is associated with abnormal DNA methylation and other epigenetic modifications, as well as altered expression of genes important for development and function of reproductive tissues. Here we review the literature exploring the connections between developmental exposure to EDCs and adult reproductive dysfunction, and the mechanisms underlying these effects.

Uterine responses to feeding soy protein isolate and treatment with 17β-estradiol differ in ovariectomized female rats

There are concerns regarding reproductive toxicity from consumption of soy foods, including an increased risk of endometriosis and endometrial cancer, as a result of phytoestrogen consumption. In this study, female rats were fed AIN-93G diets made with casein (CAS) or soy protein isolate (SPI) from postnatal day (PND) 30, ovariectomized on PND 50 and infused with 5 μg/kg/d 17β-estradiol (E2) or vehicle. E2 increased uterine wet weight (P<0.05). RNAseq analysis revealed that E2 significantly altered expression of 1991 uterine genes (P<0.05). SPI feeding had no effect on uterine weight and altered expression of far fewer genes than E2 at 152 genes (P<0.05). Overlap between E2 and SPI genes was limited to 67 genes. Functional annotation analysis indicated significant differences in uterine biological processes affected by E2 and SPI and little evidence for recruitment of estrogen receptor (ER)α to the promoters of ER-responsive genes after SPI feeding. The major E2 up-regulated uterine pathways were carcinogenesis and extracellular matrix organization, whereas SPI feeding up-regulated uterine peroxisome proliferator activated receptor (PPAR) signaling and fatty acid metabolism. The combination of E2 and SPI resulted in significant regulation of 504 fewer genes relative to E2 alone. The ability of E2 to induce uterine proliferation in response to the carcinogen dimethybenz(a)anthracene (DMBA) as measured by expression of PCNA and Ki67 mRNA was suppressed by feeding SPI (P<0.05). These data suggest that SPI is a selective estrogen receptor modulator (SERM) interacting with a small sub-set of E2-regulated genes and is anti-estrogenic in the presence of endogenous estrogens.

Types of Infant Formulas Consumed in the United States

We examined consumption of different types of infant formula (eg, cow's milk, soy, gentle/lactose-reduced, and specialty) and regular milk among a nationally representative sample of 1864 infants, 0 to 12 months old, from the National Health and Nutrition Examination Survey, 2003-2010. Among the 81% of infants who were fed formula or regular milk, 69% consumed cow's milk formula, 12% consumed soy formula, 5% consumed gentle/ lactose-reduced formulas, 6% consumed specialty formulas, and 13% consumed regular milk products. There were differences by household education and income in the percentage of infants consuming cow's milk formula and regular milk products. The majority of infants in the United States who were fed formula or regular milk consumed cow's milk formula (69%), with lower percentages receiving soy, specialty, gentle/sensitive, or lactose-free/reduced formulas. Contrary to national recommendations, 13% of infants younger than 1 year consumed regular milk, and the percentage varied by household education and income levels.

Compared with feeding infants breast milk or cow-milk formula, soy formula feeding does not affect subsequent reproductive organ size at 5 years of age

BACKGROUND

Literature reports suggest that phytochemicals, such as isoflavones found in soybeans, impair reproductive function in animals and raise the possibility that consuming soy infant formula could alter hormonally sensitive organ development in children.

OBJECTIVE

This study compared reproductive organs volumes and structural characteristics in children at age 5 y who were enrolled in the Beginnings study long-term cohort.

METHODS

Breast bud, uterus, ovaries, prostate, and testes volumes and characteristics were assessed by ultrasonography in 101 children (50 boys and 51 girls) aged 5 y who were breastfed (n = 35) or fed cow-milk formula (n = 32) or soy formula (n = 34) as infants. Analyses were adjusted for race, gestational age, and birth weight.

RESULTS

Among girls, no significant differences were found in breast bud, ovarian, or uterine volumes; counts of ovaries with cysts; ovarian cysts numbers; ovarian cyst size; and uterine shape between the diet groups. Among boys, no significant differences were found in breast bud, testes, or prostate volumes or structural characteristics between the diet groups.

CONCLUSIONS

In this cohort, no early infant feeding effects were found on reproductive organs volumes and structural characteristics in children age 5 y. The follow-up of these children through puberty is planned and should help delineate potential early infant feeding effect on reproductive function later in life.

Absorption, distribution, metabolism, and excretion of isoflavonoids after soy intake

Soy is the major source of dietary exposure to isoflavonoids (IFLs). Accumulating evidence supports a role for soy and IFLs in the protection against many chronic diseases including cancer. After soy intake we found a biphasic IFL appearance pattern in plasma as well as in urine that we suggest to be due to IFL absorption in the small intestine (ca. 10%) during the first 2h after intake and IFL absorption in the large intestine (ca. 90%) 4-6 h after intake. While each IFL disappears from the circulation at different times excellent correlations between urinary and circulating IFL values were discovered and algorithms to convert urinary excretion values into circulating levels were established. We suggest the term 'apparent bioavailability' when using urinary data to describe IFL exposure. The IFL bioavailability was found to be influenced by gut bacteria, oral antibiotic treatment (OABX), and an individual's age and health status. While daidzein (DE) and genistein start to be absorbed minutes after intake, equol (EQ) appears in plasma only after a minimum of 8h following soy intake owing to the required transit time of DE to the colon where the conversion of DE to EQ takes place by intestinal microbiota. We have also shown that the apparent IFL bioavailability is higher in children than adults, higher in healthy versus non-healthy individuals, and decreased in children but increased in adults during OABX. Finally, we propose to use a urinary EQ/DE ratio of 0.018 with a DE threshold to identify EQ producers. With this cutoff definition we observed that EQ production is inconsistent over time in 5-30% of both premenopausal and postmenopausal women.

Nursing supports neonatal porcine testicular development

The lactocrine hypothesis suggests a mechanism whereby milk-borne bioactive factors delivered to nursing offspring affect development of neonatal tissues. The objective of this study was to assess whether nursing affects testicular development in neonatal boars as reflected by: (1) Sertoli cell number and proliferation measured by GATA-4 expression and proliferating cell nuclear antigen immunostaining patterns; (2) Leydig cell development and steroidogenic activity as reflected by insulin-like factor 3 (INSL3), and P450 side chain cleavage (scc) enzyme expression; and (3) expression of estrogen receptor-alpha (ESR1), vascular endothelial growth factor (VEGF) A, and relaxin family peptide receptor (RXFP) 1. At birth, boars were randomly assigned (n = 6-7/group) to nurse ad libitum or to be pan fed porcine milk replacer for 48 h. Testes were collected from boars at birth, before nursing and from nursed and replacer-fed boars at 50 h on postnatal day (PND) 2. Sertoli cell proliferating cell nuclear antigen labeling index increased (P < 0.01) from birth to PND 2 in nursed, but not in replacer-fed boars. Sertoli cell number and testicular GATA-4 protein levels increased (P < 0.01) from PND 0 to PND 2 only in nursed boars. Neither age nor nursing affected testicular INSL3, P450scc, ESR1, or VEGFA levels. However, testicular relaxin family peptide receptor 1 (RXFP1) levels increased (P < 0.01) with age and were greater in replacer-fed boars on PND 2. Results suggest that nursing supports neonatal porcine testicular development and provide additional evidence for the importance of lactocrine signaling in pigs.

Soy infant formula and seizures in children with autism: a retrospective study

Seizures are a common phenotype in many neurodevelopmental disorders including fragile X syndrome, Down syndrome and autism. We hypothesized that phytoestrogens in soy-based infant formula were contributing to lower seizure threshold in these disorders. Herein, we evaluated the dependence of seizure incidence on infant formula in a population of autistic children. Medical record data were obtained on 1,949 autistic children from the SFARI Simplex Collection. An autism diagnosis was determined by scores on the ADI-R and ADOS exams. The database included data on infant formula use, seizure incidence, the specific type of seizure exhibited and IQ. Soy-based formula was utilized in 17.5% of the study population. Females comprised 13.4% of the subjects. There was a 2.6-fold higher rate of febrile seizures [4.2% versus 1.6%, OR = 2.6, 95% CI = 1.3–5.3], a 2.1-fold higher rate of epilepsy comorbidity [3.6% versus 1.7%, OR = 2.2, 95% CI = 1.1–4.7] and a 4-fold higher rate of simple partial seizures [1.2% versus 0.3%, OR = 4.8, 95% CI = 1.0–23] in the autistic children fed soy-based formula. No statistically significant associations were found with other outcomes including: IQ, age of seizure onset, infantile spasms and atonic, generalized tonic clonic, absence and complex partial seizures. Limitations of the study included: infant formula and seizure data were based on parental recall, there were significantly less female subjects, and there was lack of data regarding critical confounders such as the reasons the subjects used soy formula, age at which soy formula was initiated and the length of time on soy formula. Despite these limitations, our results suggest that the use of soy-based infant formula may be associated with febrile seizures in both genders and with a diagnosis of epilepsy in males in autistic children. Given the lack of data on critical confounders and the retrospective nature of the study, a prospective study is required to confirm the association.

Feeding soy protein isolate and treatment with estradiol have different effects on mammary gland morphology and gene expression in weanling male and female rats

Isoflavones are phytochemical components of soy diets that bind weakly to estrogen receptors (ERs). To study potential estrogen-like actions of soy in the mammary gland during early development, we fed weanling male and female Sprague-Dawley rats a semipurified diet with casein as the sole protein source from postnatal day 21 to 33, the same diet substituting soy protein isolate (SPI) for casein, or the casein diet supplemented with estradiol (E2) at 10 μg/kg/day. In contrast to E2, the SPI diet induced no significant change in mammary morphology. In males, there were 34 genes for which expression was changed ≥2-fold in the SPI group vs. 509 changed significantly by E2, and 8 vs. 174 genes in females. Nearly half of SPI-responsive genes in males were also E2 responsive, including adipogenic genes. Serum insulin was found to be decreased by the SPI diet in males. SPI and E2 both downregulated the expression of ERα ( Esr1) in males and females, and ERβ ( Esr2) only in males. Chromatin immunoprecipitation revealed an increased binding of ERα to the promoter of the progesterone receptor ( Pgr) and Esr1 in both SPI- and E2-treated males compared with the casein group but differential recruitment of ERβ. ER promoter binding did not correlate with differences in Pgr mRNA expression. This suggests that SPI fails to recruit appropriate co-activators at E2-inducible genes. Our results indicate that SPI behaves like a selective estrogen receptor modulator rather than a weak estrogen in the developing mammary gland.

Prenatal and postnatal energetic conditions and sex steroids levels across the first year of life

OBJECTIVES

Human biologists have documented variability in reproductive maturation, fertility, and cancer risk related to developmental conditions. Yet no previous studies have directly examined the impact of prenatal and postnatal energetic environments on sex steroids in infancy, a critical period for hypothalamic-pituitary-gonadal axis development. Thus, we examined the impact of maternal characteristics, birth size, and feeding practices on fecal sex steroid production in a longitudinal sample of 31 American infants followed from 2 weeks to 12 months of age.

METHODS

Maternal characteristics and birth size were collected at study enrollment, infant diet was assessed through weekly 24-h food diaries, and anthropometrics were measured weekly. Fecal estradiol and testosterone levels were assessed weekly using validated microassay RIA techniques. Mixed models were used to test for associations between maternal and birth characteristics, feeding practices, and sex steroids across the first year of life. Formal mediation analysis examined whether the relationship between infant feeding and hormone levels was mediated by infant size.

RESULTS

Maternal and birth characteristics had persistent effects on fecal sex steroid levels, with taller maternal height and larger birth size associated with lower estradiol levels in girls and higher testosterone levels in boys. Infant diet was also associated with sex steroid levels independently of infant size. Formula feeding was associated with higher estradiol levels in boys and girls and with higher testosterone in girls.

CONCLUSION

These results suggest that markers of early energy availability influence sex hormone levels with potential long-term consequences for reproductive development and function.

Clinical and follow up assessment of children in a program directed at the use of formulas for cow's milk protein allergy

OBJECTIVE

To determine clinical and follow up characteristics of children enrolled in a program to supply formulas for cow's milk allergy.

METHODS

descriptive study of a convenience sample composed of 214 children up to three years old, with clinical diagnosis of cow's milk allergy and/or standardized oral challenge, referred to the Program of Formulas for Cow's Milk Allergy at a Pediatric University Hospital, in Natal, Rio Grande do Norte, Brazil (2007/2009). Clinical-epidemiological data and formula indication (soy, protein hydrolysates or aminoacid formula) were assessed at the first consultation. Clinical response and nutritional evolution (Anthro-OMS2006) were observed after three months. Chi-square and paired t-test were used, being p<0.05 significant.

RESULTS

At the first consultation, mean age was 9.0±6.9 months. Digestive manifestations occurred in 81.8%; cutaneous ones, in 36.9% and respiratory ones in 23.8%. BMI Z-score <-2.0 standard deviations (SD) was found in 17.9% of children with isolated digestive symptoms, in 41.7% of those using cow's milk and in 8.7% of those using other formulas (p<0.01). The following formulas were used: soy in 61.2%, protein hydrolysates in 35.4% and aminoacids in 3.3%. Mean BMI Z-scores at initial consultation and after three months were, respectively: -0.24±1.47SD and 0.00±1.26SD (p=0.251), with soy formula, and -0.70±1.51SD and -0.14±1.36SD (p=0.322) with protein hydrolysates formula.

CONCLUSIONS

Digestive manifestations of cow's milk allergy were preponderant, and lead to greater nutritional impairment. The use of replacement formulas (isolated soy protein and protein hydrolysates) was important to maintain the nutritional status.

Soy Infant Formula may be Associated with Autistic Behaviors

The effects of soy-based infant formulas on childhood development are not well understood. This exploratory study evaluates the severity of autistic behaviors in association with the use of soy-based infant formula in a population of high-functioning autistic children. Medical record data were analyzed from the Simons Foundation Autism Research Initiative Simplex Collection, which included data on infant formula use and autism diagnostic scores for 1,949 autistic children. We found exploratory associations between the use of soy-based infant formula and several autistic behaviors as assessed by line-item analysis of the Aberrant Behavior Checklist, Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule. This study provides preliminary data that the use of soy-based infant formula may be associated with specific autistic behaviors.

Diverse effects of phytoestrogens on the reproductive performance: cow as a model

Phytoestrogens, polyphenolic compounds derived from plants, are more and more common constituents of human and animal diets. In most of the cases, these chemicals are much less potent than endogenous estrogens but exert their biological effects via similar mechanisms of action. The most common source of phytoestrogen exposure to humans as well as ruminants is soybean-derived foods that are rich in the isoflavones genistein and daidzein being metabolized in the digestive tract to even more potent metabolites-para-ethyl-phenol and equol. Phytoestrogens have recently come into considerable interest due to the increasing information on their adverse effects in human and animal reproduction, increasing the number of people substituting animal proteins with plant-derived proteins. Finally, the soybean becomes the main source of protein in animal fodder because of an absolute prohibition of bone meal use for animal feeding in 1995 in Europe. The review describes how exposure of soybean-derived phytoestrogens can have adverse effects on reproductive performance in female adults.

Early life exposure to genistein and daidzein disrupts structural development of reproductive organs in female mice

In mice, exposure to isoflavones (ISO), abundant in soy infant formula, during the first 5 d of life alters structural and functional development of reproductive organs. Effects of longer exposures are unknown. The study objective was to evaluate whether exposure to a combination of daidzein and genistein in the first 10 compared to 5 d of life results in greater adverse effects on ovarian and uterine structure in adult mice. Thirteen litters of 8-12 pups were cross-fostered and randomized to corn oil or ISO (2 mg daidzein + 5 mg genistein/kg body weight/d) for the first 5 or 10 d of life. The 10-d protocol mimicked the period when infants are fed soy protein formula (SPF) but avoids the time when suckling pups can consume mother's diet. Body and organ weights, and histology of ovaries and uteri were analyzed. There were no differences in the ovary or uterus weight, number of ovarian follicles, number of multiple oocyte follicles, or percent of ovarian cysts with 5 or 10 d ISO intervention compared to respective controls. The 10-d ISO group had higher body weights from 6 d to 4 mo of age and a higher percent of hyperplasia in the oviduct than the respective control. Lower number of ovarian corpus lutea and a higher incidence of abnormal changes were reported in the uteri of both ISO groups compared to their respective controls. Five and 10-d exposure to ISO had similar long-lasting adverse effects on the structure of ovaries and uterus in adult mice. Only the 10-d ISO exposure resulted in greater body weight gain at adulthood.

Formula feeding alters hepatic gene expression signature, iron and cholesterol homeostasis in the neonatal pig

In the U.S. formula feeding remains more popular than breast-feeding. In the current study, neonatal piglets were breast fed and compared with those fed commercially available milk-based formula (milk) or soy-based formula (soy) from postnatal day 2 (PND2) until death at PND21 (the usual age of weaning). Liver weights were greater in formula-fed piglets ( P < 0.05) than in breast-fed piglets ( P < 0.05). Affymetrix array analysis revealed significant differences in hepatic gene expression signatures between piglets fed breast milk or formula, as well as between piglets fed milk or soy. In males, expression of 346 hepatic genes differed between formula-fed and breast-fed piglets, and soy-fed differed from milk-fed piglets in 277 genes. Furthermore, gene expression profiles of males differed from females, even when the same diet was consumed. Serum cholesterol was lower in piglets fed formula relative to breast-fed piglets ( P < 0.05), and this was associated with elevations in mRNA encoding cholesterol 7α-hydroxylase (CYP7A1). Consistent with the human literature, breast-fed piglets had lower hepatic iron accumulation than formula-fed piglets. Hepcidin, a major regulator of hepatic iron trafficking, was elevated in piglets fed formula relative to breast-fed piglets ( P < 0.05). Female piglets fed soy formula had increased expression of CYP3A enzymes ( P < 0.05), and soy formula feeding decreased expression of several hepatic genes considered estrogen inducible. These data suggest that: 1) gene expression profiles in neonates differ significantly depending on the diet consumed, 2) hepatic iron storage and cholesterol metabolism clearly differ between breast and formula feeding in piglets, 3) there is no evidence that soy is estrogenic in neonatal pig liver.

US assessment of estrogen-responsive organ growth among healthy term infants: piloting methods for assessing estrogenic activity

BACKGROUND

A mother's circulating estrogen increases over the third trimester, producing physiological effects on her newborn that wane postnatally. Estrogenization might be prolonged in newborns exposed to exogenous estrogens, such as isoflavones in soy formula.

OBJECTIVE

We evaluated ultrasonography for monitoring growth of multiple estrogen-responsive organs in healthy infants and developed organ-growth trajectories.

MATERIALS AND METHODS

We studied 38 boys (61 visits) from birth to age 6 months and 41 girls (96 visits) from birth to age 1 year using a partly cross-sectional, partly longitudinal design. We measured uterus and ovaries in girls, testes and prostate in boys, and kidneys, breasts, thymus, and thyroid in all children. We imaged all organs from the body surface in one session of < 1 h.

RESULTS

Uterine volume decreased from birth (P < 0.0001), whereas ovarian volume increased sharply until age 2 months and then decreased (P < 0.001). Testicular volume increased with age (P < 0.0001), but prostatic volume showed minimal age trend. Breast bud diameter showed no age trend in girls but declined from birth in boys (P = 0.03).

CONCLUSION

US examination of multiple estrogen-responsive organs in infants in a single session is feasible and yields volume estimates useful for assessing potential endocrine disruptor effects on organ growth.

Early exposure to soy isoflavones and effects on reproductive health: a review of human and animal studies

Soy isoflavones are phytoestrogens with potential hormonal activity due to their similar chemical structure to 17-β-estradiol. The increasing availability of soy isoflavones throughout the food supply and through use of supplements has prompted extensive research on biological benefits to humans in chronic disease prevention and health maintenance. While much of this research has focused on adult populations, infants fed soy protein based infant formulas are exposed to substantial levels of soy isoflavones, even when compared to adult populations that consume a higher quantity of soy-based foods. Infant exposure, through soy formula, primarily occurs from birth to one year of life, a stage of development that is particularly sensitive to dietary and environmental compounds. This has led investigators to study the potential hormonal effects of soy isoflavones on later reproductive health outcomes. Such studies have included minimal human data with the large majority of studies using animal models. This review discusses key aspects of the current human and animal studies and identifies critical areas to be investigated as there is no clear consensus in this research field.