Milk intake and total dairy consumption: associations with early menarche in NHANES 1999-2004

Evaluating Phthalates and Bisphenol in Foods: Risks for Precocious Puberty and Early-Onset Obesity

Recent scientific results indicate that diet is the primary source of exposure to endocrine-disrupting chemicals (EDCs) due to their use in food processing, pesticides, fertilizers, and migration from packaging to food, particularly in plastic or canned foods. Although EDCs are not listed on nutrition labels, their migration from packaging to food could inadvertently lead to food contamination, affecting individuals by inhalation, ingestion, and direct contact. The aim of our narrative review is to investigate the role of phthalates and bisphenol A (BPA) in foods, assessing their risks for precocious puberty (PP) and early-onset obesity, which are two clinical entities that are often associated and that share common pathogenetic mechanisms. The diverse outcomes observed across different studies highlight the complexity of phthalates and BPA effects on the human body, both in terms of early puberty, particularly in girls, and obesity with its metabolic disruptions. Moreover, obesity, which is independently linked to early puberty, might confound the relationship between exposure to these EDCs and pubertal timing. Given the potential public health implications, it is crucial to adopt a precautionary approach, minimizing exposure to these EDCs, especially in vulnerable populations such as children.

Association between BMI and age at menarche or spermarche among both sexes: Findings from six successive national surveys in China

Background

To explore trends of the association between body mass index (BMI) and age at menarche or spermarche and its urban-rural disparities from 1995 to 2019.

Methods

A total of 912 753 children and adolescents - including 519 940 9-18 years old girls and 392 813 11-18 years old boys - were involved in six successive cross-sectional surveys conducted across 30 provinces in China from 1995 to 2019. Data on menarche and spermarche was collected using the status quo method, where same-gender physicians conducted face-to-face interviews to determine if children and adolescents had experienced their first menstrual cycle or ejaculation (yes/no). The median age at menarche or spermarche was estimated by probit analysis. Anthropometric measurements measured the height and weight of the study subjects. Children and adolescents were classified into thinness, normal range of weight, overweight, and obesity. t test was used to compare the differences in BMI between premenarchal and postmenarchal girls or prespermarcheal and postspermarcheal boys. Logistic regression was used to explore the associations between BMI/nutritional status and menarche or spermarche stratified by urban or rural residency status.

Results

From 1995 to 2019, BMI in all age groups growth over time, and the values of BMI among children and adolescents under 15 who had menarche or spermarche were more significant than those without menarche or spermarche. In 2019, for girls, thinness was associated with delayed menarche (odds ratio (OR) = 0.26; 95% confidence interval (CI) = 0.24-0.28), while overweight (OR = 1.99; 95% CI = 1.85-2.14) and obesity (OR = 2.20; 95% CI = 1.92-2.53) was associated with advanced menarche. For boys, thinness was associated with delayed spermarche (OR = 0.71; 95% CI = 0.65-0.78), overweight was associated with advanced spermarche (OR = 1.08; 95% CI = 1.01-1.15) while obesity had no association with spermarche. The OR between BMI and menarche in 1995 was 1.35 (95% CI = 1.33-1.37), which decreased to 1.19 (95% CI = 1.18-1.20) by 2019. The OR between BMI and spermarche in 1995 was 1.10 (95% CI = 1.09-1.11), which decreased to 1.02 (95% CI = 1.02-1.03) by 2019. The trends by urban-rural stratification were consistent with the total sample.

Conclusions

We have established a dose-response relationship between BMI and menarche in girls, whereas the association appears to be nonlinear in boys, and the associations were diminishing. Similar findings were observed in both urban and rural areas. Considering the dual adverse effects of obesity and early puberty on health, the results of this study suggest that sexual health education should be strengthened, especially among obese girls. Further research on the influencing factors and biological mechanisms of early puberty will be beneficial.

Genetic correlation and Mendelian randomization analyses support causal relationships between dietary habits and age at menarche

Dietary habits are essential in the mean age at menarche (AAM). However, the causal relationship between these factors remains unclear. Therefore, this study aimed to elucidate the genetic relationship between dietary habits and AAM. Genetic summary statistics for dietary habits were obtained from the UK Biobank. GWAS summary data for AAM was obtained from the ReproGen Consortium. Linkage disequilibrium score regression was used to test genetic correlations between dietary habits and AAM. The Mendelian randomization (MR) analyses used the inverse-variance weighted method. Genetic correlations with AAM were identified for 29 candi-date dietary habits, such as milk type (skimmed, semi-skimmed, full cream; coefficient = 0.2704, Pldsc = 1.13 × 10-14). MR evaluations revealed that 19 dietary habits were associated with AAM, including bread type (white vs. any other; OR 1.71, 95% CI 1.28-2.29, Pmr = 3.20 × 10-4), tablespoons of cooked vegetables (OR 0.437, 95% CI 0.29-0.67; Pmr = 1.30 × 10-4), and cups of coffee per day (OR 0.72, 95% CI 0.57-0.92, Pmr = 8.31 × 10-3). These results were observed to be stable under the sensitivity analysis. Our study provides potential insights into the genetic mechanisms underlying AAM and evidence that dietary habits are associated with AAM.

A review of dairy food intake for improving health among black children and adolescents in the US

Adequate nutrition during childhood and adolescence is crucial for proper neurological, musculoskeletal, immunological, and cardiometabolic health and development. Yet, disparities among socially underserved racial/ethnic groups in the United States (US) provide significant challenges to achieving adequate nutrition during these years of rapid growth and maturation. For example, Black children and adolescents are at greater risk for having food insecurity, lower-quality diets, obesity, and numerous associated health challenges that result from these disparities compared to their White peers. A growing body of evidence indicates that improving diet quality is critical for improving childhood and adolescent health and well-being, and that the diverse nutritional profile and bioactive compounds found within dairy foods may play multiple roles in promoting proper growth and development during these life stages. Therefore, to support overall health and development among Black youth, greater education and implementation efforts are needed to help this population meet the national dietary recommendations of 2.5 to 3 servings of dairy foods per day. Continuing to fall short of these recommendations puts Black children and adolescents at risk of multiple nutrient inadequacies and health disparities that can have lifelong impacts on disease development, mental health, and quality of life. This review presents the state of knowledge on health disparities and modifiable nutritional strategies involving milk and dairy foods to support the growth and maturation of children and adolescents, with a special focus on Black youth in the US.

Endocrine Disruptors and Metabolic Changes: Impact on Puberty Control

OBJECTIVE

This study aims to explore the significant impact of environmental chemicals on disease development, focusing on their role in developing metabolic and endocrine diseases. The objective is to understand how these chemicals contribute to the increasing prevalence of precocious puberty, considering various factors, including epigenetic changes, lifestyle, and emotional disturbances.

METHODS

The study employs a comprehensive review of descriptive observational studies in both human and animal models to identify a degree of causality between exposure to environmental chemicals and disease development, specifically focusing on endocrine disruption. Due to ethical constraints, direct causation studies in human subjects are not feasible; therefore, the research relies on accumulated observational data.

RESULTS

Puberty is a crucial life period with marked physiological and psychological changes. The age at which sexual characteristics develop is changing in many regions. The findings indicate a correlation between exposure to endocrine-disrupting chemicals and the early onset of puberty. These chemicals have been shown to interfere with normal hormonal processes, particularly during critical developmental stages such as adolescence. The research also highlights the interaction of these chemical exposures with other factors, including nutritional history, social and lifestyle changes, and emotional stress, which together contribute to the prevalence of precocious puberty.

CONCLUSION

Environmental chemicals significantly contribute to the development of certain metabolic and endocrine diseases, particularly in the rising incidence of precocious puberty. Although the evidence is mainly observational, it adequately justifies regulatory actions to reduce exposure risks. Furthermore, these findings highlight the urgent need for more research on the epigenetic effects of these chemicals and their wider impact on human health, especially during vital developmental periods.

Mother's age at menarche is associated with odds of preterm delivery: A case-control study

OBJECTIVE

There is a secular trend towards earlier age of menarche in the US and globally. Earlier age at menarche (AAM) has been associated with metabolic disorders that increase risk for preterm delivery (PTD), yet no studies in the US have investigated whether AAM influences risk of PTD. This study tested the hypothesis that AAM is associated with PTD.

DESIGN

A case-control study.

SETTING

The Boston Medical Center (BMC) in Boston, Massachusetts.

POPULATION OR SAMPLE

8264 mother-newborn dyads enrolled at birth at BMC between 1998 and 2019, of which 2242 mothers had PTD (cases) and 6022 did not have PTD (controls).

METHODS

Multivariable-adjusted logistic regression models and restricted cubic splines were used to examine the association between AAM and risk of PTD. The combined impact of AAM and age at delivery on the risk of PTD was also examined.

MAIN OUTCOME MEASURES

Preterm delivery and gestational age (GA) was defined by maternal last menstrual period and early ultrasound documented in medical records.

RESULTS

Maternal age at delivery was 28.1 ± 6.5 years and AAM was 12.85 ± 1.86 years. Multivariable-adjusted cubic spline suggested an inverse dose-response association of AAM with odds of PTD and, consistently, a positive association with GA. A 1-year earlier AAM was associated with 5% (95% CI 2%-8%) higher odds of PTD, after adjustment for maternal year of birth, parity, maternal place of birth, education, smoking status and Mediterranean-style diet score. The association between AAM and PTD was stronger among older mothers whose age at delivery was ≥35 years.

CONCLUSIONS

Earlier AAM is associated with higher odds for PTD, and this association is stronger among women at advanced reproductive age.

Dietary pattern and precocious puberty risk in Chinese girls: a case-control study

BACKGROUND

The role of dietary intake on precocious puberty remains unclear. This study aimed to investigate the association between the amount and frequency of dietary intake and the risk of precocious puberty in Chinese girls.

METHODS

In this case-control study, we enrolled 185 precocious puberty girls and 185 age-matched controls. Their dietary intake was assessed through a semi-quantitative food frequency questionnaire. Their sociodemographic and lifestyle data were collected. The associations between dietary intake and risk of precocious puberty were assessed by conditional logistic regression models.

RESULTS

After multivariate adjustment, consuming a higher amount of red meat was associated with higher precocious puberty risk (OR = 2.74, 95% CI: 1.25-6.02), while a higher frequency of fruit ( P for trend = 0.024) and amount of vegetable intake was associated with a lower risk of precocious puberty (P for trend = 0.002). The high vegetable and protein dietary pattern was significantly negatively associated with precocious puberty (OR = 0.78, 95% CI: 0.63-0.97), whereas the high animal food and fruits dietary pattern was remarkably positively associated with precocious puberty (OR = 1.36, 95% CI: 1.09-1.69), after adjusting for age and body mass index.

CONCLUSIONS

High vegetable and protein dietary pattern is a protective factor against precocious puberty, while high animal food and fruits dietary pattern is a risk factor for precocious puberty in Chinese girls. Attentions should be paid to a reasonable intake of red meat, eggs, and fruits in children's daily diet, increase their intake of vegetables, in order to reduce the risk of precocious puberty.

Why is Korean girls' suicidal ideation rate higher than boys' rate? The role of gender heterogeneity in peer groups

Girls typically show much lower suicide rates than boys in most OECD countries. However, in South Korea, the suicide rate of girls almost reaches that of boys. Moreover, Korean girls' suicide rate is remarkable even among other advanced countries. One potential approach to explaining Korean girls' relatively high suicide rate is to investigate how their peer groups affect suicidal ideation, but this approach has rarely been explored in Korean adolescents. We tested how the gender heterogeneity of peer groups is associated with suicidal ideation by analyzing 2,990 adolescents from the 2018 Korean Children and Youth Well-Being Index Survey. For the analysis, logistic regression models with survey weights were used. The analysis revealed that adolescents with different-gender friends were associated with a higher likelihood of suicidal ideation than those with exclusively same-gender friends when adjusting for covariates. In addition, an analysis stratified by gender found that this association was significant only among girls. Furthermore, the protective power of having a mentor against suicidal ideation was significantly lower in girls with male and female friends than in girls with only female friends. The findings suggest a less protective role of different-gender peer groups for suicidal ideation among girls. During adolescent suicidality consultations, school counselors and practitioners should pay attention to the characteristics of adolescents' peers, particularly their gender.

Adherence to the Mediterranean Diet in Women and Reproductive Health across the Lifespan: A Narrative Review

The Mediterranean diet (MD) has been previously proven to have various health-related benefits; however, its effect on women's reproductive health over a lifespan is yet to be summarized. This study aimed to summarize the evidence-based knowledge regarding the association between the MD and selected reproductive health outcomes. By searching PubMed, ScienceDirect, and Google Scholar databases, as well as reference lists, 21 studies were included in this narrative review. The available evidence was very limited; however, there is some suggestion that higher adherence to the MD may be positively associated with a lower risk of early age menarche (1 study) and shorter menstrual cycles (1 study), but is unrelated to dysmenorrhea (1 study). Moreover, no study to date has examined the relationship between the MD and the onset age of natural menopause. Considering reproductive health diseases, there was limited evidence that a higher adherence to the MD was associated with a lower risk of premenstrual syndrome (1 study), an improvement in sexual health and a lower prevalence of sexual dysfunction (3 studies), and an improvement in the general condition of with endometriosis and the pain they can experience (1 study). The largest number of studies were found for polycystic ovarian syndrome (PCOS; 7 studies) and infertility (6 studies). Results showed that a higher adherence to the MD was associated with a lower risk of infertility, while results for PCOS were unclear, but mostly indicated a beneficial trend. Further investigations are necessary to establish the role of adherence to the MD in reproductive health maintenance and its possible role in the prevention and treatment of reproductive health diseases in women.

The Role of Cow's Milk Consumption in Breast Cancer Initiation and Progression

PURPOSE OF REVIEW

This review evaluates cow milk's impact on breast carcinogenesis by linking recent epidemiological evidence and new insights into the molecular signaling of milk and its constituents in breast cancer (BCa) pathogenesis.

RECENT FINDINGS

Recent prospective cohort studies support the association between cow's milk consumption and the risk of estrogen receptor-α-positive (ER+) BCa. Milk is a complex biological fluid that increases systemic insulin-like growth factor 1 (IGF-1), insulin and estrogen signaling, and interacting hormonal promoters of BCa. Further potential oncogenic components of commercial milk include exosomal microRNAs (miR-148a-3p, miR-21-5p), bovine meat and milk factors, aflatoxin M1, bisphenol A, pesticides, and micro- and nanoplastics. Individuals with BRCA1 loss-of-function mutations and FTO and IGF1 gain-of-function polymorphisms enhancing IGF-1/mTORC1 signaling may be at increased risk for milk-induced ER+ BCa. Recent prospective epidemiological and pathobiochemical studies identify commercial milk consumption as a critical risk factor of ER+ BCa. Large meta-analyses gathering individuals of different ethnic origins with milk derived from dairy cows of varying genetic backgrounds and diverse feeding procedures as well as missing data on thermal processing of milk (pasteurization versus ultra-heat treatment) make multi-national meta-analyses unsuitable for BCa risk estimations in susceptible populations. Future studies are required that consider all vulnerable periods of breast carcinogenesis to cow's milk exposure, beginning during the perinatal period and puberty, since these are the most critical periods of mammary gland morphogenesis. Notwithstanding the need for better studies including detailed information on milk processing and vulnerable periods of human breast carcinogenesis, the available evidence suggests that dietary guidelines on milk consumption may have to be reconsidered.

Lower adherence to a prudent dietary pattern is associated with earlier age at menarche in adolescents from the Growth and Obesity Chilean Cohort Study

Introduction

Early menarche is associated with obesity, and metabolic and mental health risks, among other diseases. Thus, it is relevant to identify modifiable risk factors of early menarche. Some nutrients and foods have been linked to pubertal timing, but how menarche relates to overall dietary patterns is unclear.

Methods

The aim of this study was to analyze the association between dietary patterns and age at menarche in a prospective cohort of Chilean girls from low and middle-income families. We conducted a survival analysis of 215 girls (median = 12.7 years, IQR = 12.2-13.2) from the Growth and Obesity Cohort Study (GOCS) who had been followed prospectively since 4 years of age (2006). Age at menarche and anthropometric measurements were recorded every 6 months since 7 years of age while diet (24-hour dietary recall) was collected for 11 years. Dietary patterns were obtained from exploratory factor analysis. Accelerated Failure Time models adjusted for potential confounding variables were used to study the association between dietary patterns and age at menarche.

Results

Girls' median age at menarche was 12.7 years. Three dietary patterns were identified: "Breakfast/Light Dinner," "Prudent" and "Snacking" which explained 19.5% of the diet variation. Girls in the lowest tertile of the "Prudent" pattern had menarche 3 months earlier than girls in the highest tertile (β: 0.022; 95% CI: 0.003; 0.041). "Breakfast/Light Dinner" and "Snacking" patterns were not associated with age at menarche.

Conclusion

Our results suggest that healthier dietary patterns during puberty might be associated with menarche timing. Nevertheless, further studies are required to confirm this result and to clarify the association between diet and puberty.

Links between Childhood Obesity, High-Fat Diet, and Central Precocious Puberty

In recent years, the existing relationship between excess overweight and central precocious puberty (CPP) has been reported, especially in girls. Different nutritional choices have been associated with different patterns of puberty. In particular, the involvement of altered biochemical and neuroendocrine pathways and a proinflammatory status has been described in connection with a high-fat diet (HFD). In this narrative review, we present an overview on the relationship between obesity and precocious pubertal development, focusing on the role of HFDs as a contributor to activating the hypothalamus-pituitary-gonadal axis. Although evidence is scarce and studies limited, especially in the paediatric field, the harm of HFDs on PP is a relevant problem that cannot be ignored. Increased knowledge about HFD effects will be useful in developing strategies preventing precocious puberty in children with obesity. Promoting HFD-avoiding behavior may be useful in preserving children's physiological development and protecting reproductive health. Controlling HFDs may represent a target for policy action to improve global health.

Association of the consumption of common drinks with early puberty in both sexes

Background

We examined the effect of sugar-sweetened beverages (SSB) and common drink intake on pubertal development in both sexes.

Methods

Data were retrieved from Taiwan Children Health Study, which involved detailed pubertal stage assessments of 2,819 schoolchildren aged 11 years in 2011-2012. Drawings of secondary sexual characteristics and self-reported age at menarche or voice breaking were used to assess pubertal stages. Dietary intake was assessed using a detailed semi-quantitative food frequency questionnaire. Generalized estimating equation modeling was applied to obtain odds ratios (ORs) and 95% confidence intervals (CIs) to represent the effects of each drink on early pubertal development outcomes.

Results

In boys, an one cup/day increment of a SSB was associated with earlier voice breaking (β = -0.12; 95% CI = -0.20, -0.04), whereas consuming yogurt (≥2 cups/day) was a protective factor against early puberty (OR = 0.78; 95% CI = 0.73, 0.83). In girls, SSB consumption was associated with increased risk of early puberty in a dose-response manner, and a similar protective effect of yogurt consumption and fermented probiotic drink (≥2 cups/day) against early puberty was observed (OR = 0.96; 95% CI = 0.94, 0.99). Furthermore, the intake of both total sugar and added sugar within SSBs increased risk of early puberty in girls but not in boys.

Conclusions

Sugar-sweetened beverages were associated with early puberty, and probiotic drinks appeared to mitigate this link. These findings indicate that the gut-brain axis could play a crucial role in sexual maturation.

Diet and Nutrients Intakes during Infancy and Childhood in Relation to Early Puberty: A Systematic Review and Meta-Analysis

The onset of puberty has become earlier over the decades, and nutrients and diet are related to the timing of puberty onset. Hence, we aimed to investigate the association between diet or nutrients in infancy, childhood and early puberty. PubMed, Embase, and Cochrane library were searched systematically up to 15 April 2022. The pooled relative risks (RRs) or regression coefficients (beta) were estimated using the random-effect model or fixed-effect model according to the heterogeneity between studies. Twenty-two articles on diet or nutrients in childhood and six about breastfeeding in infancy were included. The prolonged breastfeeding duration in infancy could reduce the risk of early menarche (beta 0.31, 95% CI: 0.01, 0.60, p = 0.045). The high intake of yogurt was associated with a 35% reduction in the risk of earlier menarche (RR 0.65, 95% CI: 0.47, 0.89, p = 0.008). Girls with severe food insecurity experienced later menarche (RR 0.81, 95% CI: 0.67, 0.98, p = 0.027). Conversely, due to the high intake of protein, the risk of early menarche increased by 8% (RR 1.08, 95% CI: 1.01, 1.16, p = 0.016). High intake of yogurt, longer duration of breastfeeding, and food insecurity decreased the possibility of earlier menarche, while high intake of protein increased that risk. As a modifiable factor, diet and nutrients in infancy and childhood provide new insights into the future prevention of early puberty.

Is age of menarche directly related to vitamin D levels?

INTRODUCTION

Very few studies have examined the direct link between age of menarche and vitamin D level and controversial results have been reported. This study aimed to investigate the association between vitamin D and age of menarche in a group of adolescent girls in an area with plenty of sunshine.

METHODS

At baseline, data were collected on 722 middle schoolgirls that were randomly selected by probability proportional to size sampling method. Of this group, 598 were followed including 173 who had their menarche during the follow-up. Serum 25-hydroxyvitamin D (25OHD) was measured at baseline using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Data on potential confounders were collected at baseline from the parents using self-administered questionnaire and from schoolgirls through face-to-face interview. Multiple linear regression and time-to-event analysis were used to investigate the association between 25OHD concentration and age of menarche.

RESULTS

The mean (SD) age of the study group was 12.51 (0.91) years while the main (SD) age of menarche was 11.82 (1.04) years. The prevalence of vitamin D deficiency (<50 nmol/L) among schoolgirls was 91.69%. We found no evidence for the association between 25OHD levels and age of menarche before (β, .00, 95% confidence interval (CI) [-0.01, 0.01]; p = .808) or after (β, .00, 95% CI [-0.01, 0.01]; p = .765) adjusting for potential confounders. We also found no evidence for association between 25OHD status and age of menarche before (p = .424) or after (p = .356) adjusting for potential confounders. Time-to-event analysis showed no association between 25OHD level or status and age of menarche (p = .850).

CONCLUSION

In Middle Eastern setting, where vitamin D deficiency is common despite plenty of sunshine, vitamin D is not a major determinant of the age at menarche. Regardless of the link between vitamin D and age of menarche, there are several other health benefits of having adequate vitamin D level during childhood and adolescence.

Review Nutritional interventions during adolescence and their possible effects

Nutrition is one of the most important factors affecting pubertal development. Increasing demands for energy proteins and micronutrients are necessary to cope with the rapid linear pubertal growth and development, change in body composition, and increased physical activity. Adequate nutrition is a key permissive factor for the normal timing and tempo of pubertal development. Severe primary or secondary malnutrition also can adversely delay the onset and progression of puberty. The higher incidence of anorexia nervosa and bulimia in adolescents imposes a nutritional risk on pubertal development. Here we provide an overview of nutritional requirements (macronutrients and micronutrients) necessary to cope with these changes. In addition, we discuss possible nutritional interventions trials and their effects on several aspects of growth and development in undernourished and stunted adolescents, in low- and middle-income countries (LMIC), who require nutritional rehabilitation. This mini-review sums up some important findings in this important complex that links between nutrition, nutritional interventions, and pubertal development.

In Vivo Study of The Oestrogenic Activity of Milk

Introduction

Milk has been suggested to be a possible source of oestrogenically active compounds. In order to assess the health risk for milk consumers and ensure the safety of this staple part of the human diet, it is important to study the effect of xenooestrogen mixtures present in milk. This investigation used the available in vivo model to learn to what extent such compounds may be endocrine disruptors.

Material and Methods

The recommended immature golden hamster uterotrophic bioassay was chosen. A total of 132 animals were divided into nine groups of experimental animals and positive and negative control groups, each of 12 animals. The experimental females received ad libitum either one of five samples of raw cow’s milk from individual animals or one of four samples of pasteurised or ultra-high temperature treated cow’s milk as retail products. After 7 days, the animals were sacrificed and necropsied. Uterine weight increases were measured as the endpoint of oestrogenic activity in milk.

Results

The milk samples from individual cows and the retail milk samples did not show oestrogenic activity. However, in three groups, decreased uterine weights were observed.

Conclusion

Considering that milk supplies are beneficial to health, contamination in this food should be avoided. There is a need for further animal experiments and epidemiological studies are warranted to evaluate any causative role of milk in human endocrinological disorders.

The Role of Pediatric Nutrition as a Modifiable Risk Factor for Precocious Puberty

Puberty is a critical phase of growth and development characterized by a complex process regulated by the neuroendocrine system. Precocious puberty (PP) is defined as the appearance of physical and hormonal signs of pubertal development at an earlier age than is considered normal. The timing of puberty has important public health, clinical, and social implications. In fact, it is crucial in psychological and physical development and can impact future health. Nutritional status is considered as one of the most important factors modulating pubertal development. This narrative review presents an overview on the role of nutritional factors as determinants of the timing of sexual maturation, focusing on early-life and childhood nutrition. As reported, breast milk seems to have an important protective role against early puberty onset, mainly due to its positive influence on infant growth rate and childhood overweight prevention. The energy imbalance, macro/micronutrient food content, and dietary patterns may modulate the premature activation of the hypothalamic-pituitary-gonadal axis, inducing precocious activation of puberty. An increase in knowledge on the mechanism whereby nutrients may influence puberty will be useful in providing adequate nutritional recommendations to prevent PP and related complications.

Longitudinal association of dietary sources of animal and plant protein throughout childhood with menarche

Background

Inconsistent findings have been reported for associations between protein intake and age at menarche. We aimed to investigate the association between intake of protein and protein-containing food groups during childhood with menarche among Iranian girls.

Methods

Girls aged 6–18 years who did not experience menarche in the third or fourth examination cycles of the Tehran Lipid and Glucose Study were selected and were followed to the fifth examination cycle. Daily intakes of protein from different animal/plant sources and ten protein-containing food groups were assessed using a food frequency questionnaire at baseline (the third or fourth examination cycles). Occurrence of menarche and its onset age were asked during each examination cycle. Cox proportional hazards regression was used to estimating hazard ratios (HRs) and 95% confidence interval (95%CI) for the occurrence of menarche per one standard deviation (SD) of dietary intakes. Logistic regression was also used to estimate the odds of reaching menarche ≤12 years.

Results

During the study, 147(61%) of girls reached menarche, the median age at menarche was 12 years. The adjusted HRs (95% CI) for the occurrence of menarche per one-SD of dietary intakes were 0.68 (0.48, 0.98; p = 0.040) for plant protein and 1.36 (1.01, 1.84; p = 0.042) for animal protein after adjusting for baseline age, BMI Z-score, energy intake, and mother’s early menarche and education. Substituting 10-g animal protein with plant protein was associated with a 16% (95%CI: 5–25%; p = 0.006) lower risk of menarche. Dietary intakes of poultry (adjusted HR: 1.35; 95% CIs: 1.00–1.82; p = 0.049) and low-fat dairy (adjusted HR: 1.20; 95%CIs: 0.99–1.46; p = 0.064) were marginally associated with the increased risk of menarche. However, the odds of early menarche was significant only for plant protein (adjusted odds ratio = 0.39; 95% CI: 0.16–0.96; p = 0.040).

Conclusions

Our findings indicate that the risk of menarche increases by higher intakes of animal protein and decreases by plant protein. Intakes of poultry and low-fat dairy associate with a higher risk of menarche. The odds of menarche occurrence ≤12 years reduces by higher intakes of plant protein.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02670-8.

[Health risks related to milk consumption: a critical evaluation from the medical perspective]

BACKGROUND

Recent epidemiological studies associate the consumption of non-fermented cow's milk, but not fermented milk products, with an increased risk of diseases of civilization.

OBJECTIVES

Presentation of epidemiological and pathophysiological data on health risks associated with milk consumption.

METHOD

Selective PubMed surveys between 2005-2020 considering epidemiological studies which clearly differentiate between non-fermented versus fermented milk and its potential health risks.

RESULTS

Epidemiological studies confirm a correlation between milk consumption and birthweight, linear growth during puberty, acne vulgaris, type 2 diabetes mellitus, prostate cancer, breast cancer, hepatocellular carcinoma, non-Hodgkin lymphoma, Parkinson's disease and over-all mortality. In comparison to milk consumption, the intake of fermented milk/milk products exhibits neutral to beneficial health effects, which are explained by attenuated mTORC1 signaling due to bacterial fermentation of milk.

CONCLUSIONS

Long-term persistent consumption of non-fermented milk, but not fermented milk/milk products, might increase the risk of diseases of civilization. The avoidance of milk, especially pasteurized fresh milk, may enhance the prevention and reduce the recurrence of common Western diseases of civilization.

Lifetime Impact of Cow's Milk on Overactivation of mTORC1: From Fetal to Childhood Overgrowth, Acne, Diabetes, Cancers, and Neurodegeneration

The consumption of cow's milk is a part of the basic nutritional habits of Western industrialized countries. Recent epidemiological studies associate the intake of cow's milk with an increased risk of diseases, which are associated with overactivated mechanistic target of rapamycin complex 1 (mTORC1) signaling. This review presents current epidemiological and translational evidence linking milk consumption to the regulation of mTORC1, the master-switch for eukaryotic cell growth. Epidemiological studies confirm a correlation between cow's milk consumption and birthweight, body mass index, onset of menarche, linear growth during childhood, acne vulgaris, type 2 diabetes mellitus, prostate cancer, breast cancer, hepatocellular carcinoma, diffuse large B-cell lymphoma, neurodegenerative diseases, and all-cause mortality. Thus, long-term persistent consumption of cow's milk increases the risk of mTORC1-driven diseases of civilization. Milk is a highly conserved, lactation genome-controlled signaling system that functions as a maternal-neonatal relay for optimized species-specific activation of mTORC1, the nexus for regulation of eukaryotic cell growth, and control of autophagy. A deeper understanding of milk´s impact on mTORC1 signaling is of critical importance for the prevention of common diseases of civilization.

Higher poultry consumption was associated with an earlier age at menarche

AIM

To examine the association between meat consumption and earlier age of menarche among schoolgirls in Shanghai.

METHODS

The study randomly selected 1981 schoolgirls aged 6-18 years in Shanghai using a two-stage random sampling design. Information on meat intake was collected using a semi-quantitative food frequency questionnaire. Menarche age, household income, physical activity and other covariates were obtained by standardised questionnaires. Logistic regression was used to analyse the association between intake of meat and earlier age of menarche. Earlier age of menarche was defined as first menstruation before 12 years of age.

RESULTS

Among the 986 girls who had experienced menarche, 518/986 (52.5%) had earlier age of menarche. After adjusting for body mass index, age, physical activity, sleep, household income and parental education, consumption of poultry was positively associated with risk of earlier age of menarche (P-trend = .03). Girls who never consumed poultry had a lower risk of earlier age of menarche (odds ratio [OR]: 0.61, 95% confidence interval [CI]: 0.39-0.96). Neither the consumption of pork, beef, lamb, processed meat nor total meat consumption was associated with menarche age.

CONCLUSION

Higher consumption of poultry was associated with an earlier age at menarche.

The Role of Fetal, Infant, and Childhood Nutrition in the Timing of Sexual Maturation

Puberty is a crucial developmental stage in the life span, necessary to achieve reproductive and somatic maturity. Timing of puberty is modulated by and responds to central neurotransmitters, hormones, and environmental factors leading to hypothalamic-pituitary-gonadal axis maturation. The connection between hormones and nutrition during critical periods of growth, like fetal life or infancy, is fundamental for metabolic adaptation response and pubertal development control and prediction. Since birth weight is an important indicator of growth estimation during fetal life, restricted prenatal growth, such as intrauterine growth restriction (IUGR) and small for gestational age (SGA), may impact endocrine system, affecting pubertal development. Successively, lactation along with early life optimal nutrition during infancy and childhood may be important in order to set up timing of sexual maturation and provide successful reproduction at a later time. Sexual maturation and healthy growth are also influenced by nutrition requirements and diet composition. Early nutritional surveillance and monitoring of pubertal development is recommended in all children, particularly in those at risk, such as the ones born SGA and/or IUGR, as well as in the case of sudden weight gain during infancy. Adequate macro and micronutrient intake is essential for healthy growth and sexual maturity.

Medieval menarche: Changes in pubertal timing before and after the Black Death

OBJECTIVES

Bioarcheological evidence suggests stature increased in males but decreased in females after the Black Death (1348-1350 CE). Because tradeoffs between growth and reproduction can result in earlier ages at menarche and lower limb length, we assess menarcheal age between 1120 and 1540 CE to better understand the health of medieval adolescent females before and after the plague.

MATERIALS AND METHODS

Our sample comprises 74 adolescent females from St. Mary Spital, London (1120-1540 CE) within the age range during which menarche occurs (10-25 years). They were assessed as being pre- or post-menarcheal and divided into three groups: Early Pre-Black Death (n = 13), Late Pre-Black Death (n = 38), and Post-Black Death (n = 23). Changes in the ages of pre- and post-menarcheal females were assessed using Mann-Whitney tests.

RESULTS

The average age of post-menarcheal females increased from the Early- to Late Pre-Black Death periods and declined after the Black Death.

CONCLUSIONS

Short stature can reflect unfavorable growth environments, while younger menarcheal age indicates improved living conditions. The paradoxical pattern of female, but not male, stature reduction after the Black Death might reflect the association of early menarche with lower limb length and signal that adolescent females experienced improved health conditions after the epidemic. Our focus on pre- and post-menarche within a limited age span provides a novel approach for inferring average ages of menarche over time. Pathways to skeletal development and reproductive investment are part of an integrated system, providing a bridge between life history research in bioarchaeology and human biology.

Greater adherence to a Mediterranean-like diet is associated with later breast development and menarche in peripubertal girls

OBJECTIVE

To examine adherence to a Mediterranean-like diet at age 9-10 years in relation to onset of breast development (thelarche) and first menstruation (menarche).

DESIGN

We evaluated the associations of adherence to a Mediterranean-like diet (measured by an adapted Mediterranean-like Diet Score, range 0-9) with thelarche at baseline, age at thelarche and time to menarche. Data were collected at baseline during a clinic visit, complemented with a mailed questionnaire and three 24 hour telephone dietary recalls, followed by annual follow-up questionnaires. Multivariable Poisson regression, linear regression and Cox proportional hazards regression were used to evaluate timing of pubertal development in relation to diet adherence.

SETTING

New Jersey, USA.

PARTICIPANTS

Girls aged 9 or 10 years at baseline (2006-2014, n 202).

RESULTS

High Mediterranean-like diet adherence (score 6-9) was associated with a lower prevalence of thelarche at baseline compared with low adherence (score 0-3; prevalence ratio = 0·65, 95 % CI 0·48, 0·90). This may have been driven by consumption of fish and non-fat/low-fat dairy. Our models also suggested a later age at thelarche with higher Mediterranean-like diet adherence. Girls with higher Mediterranean-like diet adherence had significantly longer time to menarche (hazard ratio = 0·45, 95 % CI 0·28, 0·71 for high v. low adherence). Further analysis suggested this may have been driven by vegetable and non-fat/low-fat dairy consumption.

CONCLUSIONS

Consuming a Mediterranean-like diet may be associated with older age at thelarche and menarche. Further research is necessary to confirm our findings in other US paediatric populations and elucidate the mechanism through which Mediterranean-like diet may influence puberty timing.

Dissimilar associations of same metabolic parameters with main chronic noncommunicable diseases (cancer vs some other NCDs)

Hormone-dependent tissues' cancers (mainly breast and endometrial and several others) are among the most frequent malignancies in adults and are often discussed in context of their correlation with other chronic noncommunicable diseases (NCDs), for example, cardiovascular and cerebrovascular conditions, and their risk factors, which may also be hormone metabolic. An idea that is often expressed delineates common factors leading to NCDs of malignant and nonmalignant nature. However, this idea is not always confirmed by study results. The reasons for this discrepancy are not clear and require further analysis. This editorial tries to show the importance of this problem with a few examples (in particular, by attracting information on the role of birthweight, adult height and family history of diabetes) which may help us understand some mechanisms behind interconnections of major NCDs, including cancer.

Dairy Products: Is There an Impact on Promotion of Prostate Cancer? A Review of the Literature

This review of the literature aims to study potential associations between high consumption of milk and/or dairy products and prostate cancer (PC). Literature is scarce, yet there is a direct relationship between mTORC1 activation and PC; several ingredients in milk/dairy products, when in high concentrations, increase signaling of the mTORC1 pathway. However, there are no studies showing an unequivocal relationship between milk products PC initiation and/or progression. Three different reviews were conducted with articles published in the last 5 years: (M1) PC and intake of dairy products, taking into account the possible mTORC1signaling mechanism; (M2) Intake of milk products and incidence/promotion of PC; (M3) mTORC1 activation signaling pathway, levels of IGF-1 and PC; (M4) mTORC pathway and dairy products. Of the 32 reviews identified, only 21 met the inclusion criteria and were analyzed. There is little scientific evidence that directly link the three factors: incidence/promotion of PC, intake of dairy products and PC, and PC and increased mTORC1 signaling. Persistent hyper-activation of mTORC1 is associated with PC promotion. The activity of exosomal mRNA in cellular communication may lead to different impacts of different types of milk and whether or not mammalian milks will have their own characteristics within each species. Based on this review of the literature, it is possible to establish a relationship between the consumption of milk products and the progression of PC; we also found a possible association with PC initiation, hence it is likely that the intake of dairy products should be reduced or minimized in mens' diet.

Recent advances in the detection of 17β-estradiol in food matrices: A review

Pollution of endocrine disrupting chemicals has become a global issue. As one of the hormonally active compounds, 17β-estradiol produces the strongest estrogenic effect when it enters the organism exogenously including food intakes, bringing potential harmfulness such as malfunction of the endocrine system. Therefore, in order to assure food safety and avoid potential risks of 17β-estradiol to humans, it is of great significance to develop rapid, sensitive and selective approaches for the detection of 17β-estradiol in food matrices. In this review, the harmfulness and main sources of 17β-estradiol are firstly introduced, followed by the description of the principles and applications of different approaches for 17β-estradiol detection including high performance liquid chromatography, electrochemistry, Raman spectroscopy, fluorescence and colorimetry. Particularly, applications in detecting 17β-estradiol in food matrices over the years of 2010-2018 are discussed. Finally, advantages and limitations of these detection methods are highlighted and perspectives on future developments in the detection methods for 17β-estradiol are also proposed. Although many detection approaches can achieve trace or ultratrace detection of 17β-estradiol, further studies should be focused on the development of in-situ and real-time methods to monitor and evaluate 17β-estradiol for food safety.

Diseases of Civilization - Cancer, Diabetes, Obesity and Acne - the Implication of Milk, IGF-1 and mTORC1

Nutrition and food are one of the most complex aspects of human lives, being influenced by biochemical, psychological, social and cultural factors. The Western diet is the prototype of modern dietary pattern and is mainly characterized by the intake of large amounts of red meat, dairy products, refined grains and sugar. Large amounts of scientific evidence positively correlate Western diet to acne, obesity, diabetes, heart disease and cancer, the so-called "diseases of civilization". The pathophysiological common ground of all these pathologies is the IGF-1 and mTORC pathways, which will be disscussed further in this paper.

Vegetables and lean proteins-based and processed meats and refined grains -based dietary patterns in early childhood are associated with pubertal timing in a sex-specific manner: a prospective study of children from Mexico City

Childhood diet has been implicated in timing of sexual maturation. A key limitation of published studies is the focus on individual foods rather than patterns. We hypothesized that dietary patterns characterized by fruits and vegetables during early childhood (age 3 years) would be associated with delayed pubertal timing, whereas energy-dense and meat-based dietary patterns would relate to earlier puberty. The study population included 496 participants of a Mexico City birth cohort. The exposures of interest were dietary patterns derived from principal component analysis of dietary data collected via a semiquantitative food frequency questionnaire when the children were 3 years of age, and the outcomes were physician-assessed Tanner stages for pubic hair, breast (girls), genitalia, and testicular volume (boys) between 9 and 18 years, and initiation of menarche (girls). In regression analyses, we estimated adjusted hazard ratios and 95% confidence intervals for having reached Tanner stage ≥4 or initiation of menarche in girls and testicular volume ≥15 mL in boys. Among girls, those in the highest vs lowest tertile of vegetables and lean proteins pattern had a 35% (95% confidence interval 3%-67%) lower adjusted probability of having reached breast stage ≥4. Among boys, the processed meats and refined grain pattern score was associated with more advanced testicular development (adjusted hazard ratio = 3.58 [0.62-6.53]). Early childhood dietary patterns may play a role in the tempo of sexual maturation, which could ultimately carry implications for chronic disease susceptibility.

Association between Dietary Patterns and Precocious Puberty in Children: A Population-Based Study

OBJECTIVE

The aim of the present study was to investigate the association between dietary patterns and precocious puberty among Shanghai children.

METHODS

A cross-sectional study was conducted among Shanghai children by multistage stratified cluster random sampling in June 2014. Diet was assessed using a simplified food frequency questionnaire (FFQ). Height, weight, and Tanner stages of breast development, pubic hair growth, and testicular volume were carefully measured. Exploratory factor analysis was used to identify dietary patterns, and logistic regression analysis was used to assess the association between dietary patterns and precocious puberty.

RESULTS

Three distinct dietary patterns, "traditional diet," "unhealthy diet," and "protein diet," were established. Neither the "traditional diet" pattern nor the "protein diet" pattern showed any association with precocious puberty, taking gender, BMI, and adjustment factors into consideration. The "unhealthy diet" pattern was significantly positively associated with precocious puberty in both boys (OR = 1.24, 95% CI = 1.02-1.51) and girls (OR = 1.31, 95% CI = 1.10-1.56). The relationship remained positive only for girls (OR = 1.25, 95% CI = 1.04-1.49) after adjustment for age and BMI but statistically nonsignificant after further adjustment for socioeconomic factors in both boys and girls.

CONCLUSIONS

Dietary patterns were found to be related to precocious puberty among Shanghai children.

Micronutrient status in middle childhood and age at menarche: results from the Bogotá School Children Cohort

Childhood intake of animal foods is associated with age at first menstrual period (menarche). It is unknown whether the micronutrients present in these foods could explain this association. Our objective was to investigate the associations of micronutrient status biomarkers in middle childhood with age at menarche. We quantified circulating Hb, ferritin, mean corpuscular volume, Zn, vitamin B12, erythrocyte folate and retinol in 1464 pre-menarcheal girls aged 5–12 years in Bogotá, Colombia, and followed them for a median 5·7 years for the occurrence and date of menarche. We estimated median age at menarche and hazard ratios (HR) with 95 % CI by levels of each biomarker with use of Kaplan–Meier survival probabilities and Cox regression, respectively. Median age at menarche was 12·4 years. Middle childhood Hb was inversely related to age at menarche whereas plasma ferritin was positively associated with this outcome in a linear manner. HR of menarche for every 1sdof Hb (11 g/l) and ferritin (23·2 µg/l) were 1·11 (95 % CI 1·04, 1·18;P=0·001) and 0·94 (95 % CI 0·88, 0·99;P=0·02), respectively, after adjustment for baseline age, C-reactive protein concentration, maternal age at menarche and parity and socioeconomic status. The association with ferritin was stronger in girls aged 9–10 years at baseline. Additional adjustment for baseline height- and BMI-for-age did not change the results. We conclude that higher Fe status in middle childhood is related to later age at menarche whereas Hb concentrations are inversely associated with age at onset of menses.

A 25-Hydroxycholecalciferol-Fortified Dairy Drink Is More Effective at Raising a Marker of Postprandial Vitamin D Status than Cholecalciferol in Men with Suboptimal Vitamin D Status

Background: One strategy for improving population vitamin D status is consumption of fortified foods. However, the effects of dairy products fortified with different vitamin D isoforms on postprandial vitamin D status and metabolic outcomes have not been addressed.Objective: We investigated whether consumption of dairy drinks fortified with either 25-hydroxycholecalciferol [25(OH)D₃] or cholecalciferol (vitamin D₃) had differential effects on 24-h circulating plasma 25(OH)D₃ concentration (a marker of vitamin D status) and cardiometabolic risk markers.Methods: A randomized, controlled, 3-way crossover, double-blind, postprandial study was conducted in 17 men with suboptimal vitamin D status [mean ± SEM age: 49 ± 3 y; body mass index (in kg/m²): 26.4 ± 0.6; and plasma 25(OH)D₃ concentration: 31.7 ± 3.4 nmol/L]. They were randomly assigned to consume 3 different test meals (4.54 MJ, 51 g fat, 125 g carbohydrate, and 23 g protein), which contained either a nonfortified dairy drink (control), 20 μg 25(OH)D₃-fortified (+HyD₃) dairy drink, or 20 μg vitamin D₃-fortified (+D₃) dairy drink with toasted bread and jam on different occasions, separated by a 2-wk washout. Plasma 25(OH)D₃ concentrations and cardiometabolic risk markers, including vascular stiffness, serum lipids, and inflammatory markers, were measured frequently within 8 h postprandially and 24 h after the dairy drink was consumed.Results: Plasma 25(OH)D₃ concentrations (the primary outcome) were significantly higher after the +HyD₃ dairy drink was consumed compared with +D₃ and control (P = 0.019), which was reflected in the 1.5-fold and 1.8-fold greater incremental area under the curve for the 0-8 h response, respectively. The change in plasma 25(OH)D₃ concentrations from baseline to 24 h for the +HyD₃ dairy drink was also 0.9-fold higher than the +D₃ dairy drink and 4.4-fold higher than the control (P < 0.0001), which were not significantly different from each other.Conclusion: The dairy drink fortified with 25(OH)D₃ was more effective at raising plasma 25(OH)D₃ concentrations postprandially than was the dairy drink fortified with vitamin D₃ in men with suboptimal vitamin D status. This trial was registered at clinicaltrials.gov as NCT02535910.

Peripubertal dietary flavonol and lignan intake and age at menarche in a longitudinal cohort of girls

BackgroundDietary phytoestrogens may alter hormonal activity in childhood. Flavonols and lignans are the most prevalent phytoestrogens in the Western diet. We examined whether higher intake of flavonols and lignans was associated with later age at menarche in a prospective study of young girls.MethodsIn all, 1,044 girls aged 6-8 years (mean 7.3 years) with two to four 24-h dietary recalls during their baseline year were followed up for 11 years until the attainment of menarche in the Breast Cancer and Environment Research Project (BCERP). Associations of age at menarche with quintiles of phytoestrogens were assessed using hazard ratios (HR) and 95% confidence intervals (CIs) from Cox proportional hazards models, controlling for body mass index and other covariates.ResultsThe highest quintile of flavonol intake was associated with a later age at menarche, compared with the lowest quintile (adjusted HR: 0.80, 95% CI: (0.66-1.00). For lignans, there was a later age in overweight girls (HR: 0.56, 95% CI=0.40-0.80).ConclusionThese dietary bioactives may reflect a healthy diet, and foods high in phytoestrogens may influence the timing of menarche.

Dairy intake in relation to breast and pubertal development in Chilean girls

Background: Frequent dairy consumption in childhood has been related to higher growth-hormone concentrations that may affect mammary gland and pubertal development.Objective: We evaluated the relation of dairy intake to breast composition at Tanner stage 4 and age at menarche.Design: A total of 515 Chilean girls are included in the Growth and Obesity Cohort Study. The subjects have been followed longitudinally since they were 3-4 y old (from 2006 to the present). Starting in 2013, diet was assessed every 6 mo via a 24-h recall. The breast fibroglandular volume (FGV) was measured with the use of dual-energy X-ray absorptiometry at Tanner stage 4. The date of menarche was reported every 6 mo. Our analysis included 290 girls with data on prospective diet and breast composition and 324 girls with data on prospective diet and age at menarche.Results: The mean ± SD breast FGV and percentage of fibroglandular volume (%FGV) (i.e., FGV divided by total breast volume times 100) at Tanner stage 4 was 81.7 ± 32.2 cm³ and 42.0% ± 16.7%, respectively. Only sweetened, artificially flavored milk-based drinks were associated with the %FGV with girls who consumed >125 g/d having a %FGV that was 4.5% (95% CI: 0.9%, 8.1%) higher than that of girls who consumed none (P-trend = 0.007). Yogurt intake was associated with a lower FGV. Specifically, girls who consumed >125 g yogurt/d had -10.2 cm³ (95% CI: -20.2, -0.3 cm³) less FGV than did girls who consumed no yogurt (P-trend = 0.03). The majority (90.7%) of girls in our cohort attained menarche before the data analyses with a mean ± SD age at menarche of 11.9 ± 0.7 y. In multivariable models, low-fat dairy, low-fat milk, and yogurt intakes were associated with a later age at menarche. In particular, girls who consumed >125 g yogurt/d had menarche, on average, 4.6 mo (95% CI: 1.9, 7.4 mo) later than girls who consumed no yogurt (P-trend = 0.01).Conclusion: More-frequent consumption of sweetened, artificially-flavored milk-based drinks is associated with a higher %FGV, whereas higher yogurt intake is associated with a lower FGV and delayed age at menarche in Chilean girls.

Milk's Role as an Epigenetic Regulator in Health and Disease

It is the intention of this review to characterize milk's role as an epigenetic regulator in health and disease. Based on translational research, we identify milk as a major epigenetic modulator of gene expression of the milk recipient. Milk is presented as an epigenetic "doping system" of mammalian development. Milk exosome-derived micro-ribonucleic acids (miRNAs) that target DNA methyltransferases are implicated to play the key role in the upregulation of developmental genes such as FTO, INS, and IGF1. In contrast to miRNA-deficient infant formula, breastfeeding via physiological miRNA transfer provides the appropriate signals for adequate epigenetic programming of the newborn infant. Whereas breastfeeding is restricted to the lactation period, continued consumption of cow's milk results in persistent epigenetic upregulation of genes critically involved in the development of diseases of civilization such as diabesity, neurodegeneration, and cancer. We hypothesize that the same miRNAs that epigenetically increase lactation, upregulate gene expression of the milk recipient via milk-derived miRNAs. It is of critical concern that persistent consumption of pasteurized cow's milk contaminates the human food chain with bovine miRNAs, that are identical to their human analogs. Commercial interest to enhance dairy lactation performance may further increase the epigenetic miRNA burden for the milk consumer.

Pattern of menarche age (normal, early and late) and its relationship with some demographic characteristics in girls and their parents

BACKGROUND

Menarche age is an indicator of a girl's puberty besides the clinical assessment of detecting deviations. This study aimed to search the pattern of menarche age (normal, early and late) and its relationship with some demographic characteristics in girls and their parents.

METHODS

This cross-sectional study was done on girls aged between 9 and 18 years old in Shiraz city. About 2000 students were selected through cluster sampling. Data collection was done by applying a demographic information form. Finally, the data were analyzed using SPSS software.

RESULTS

About 1386 students (69.3%) had the history of menarche (at least once). The mean age of menarche was 12.26±1.11 years in Shiraz. The menarche age of the girls ranged from 9 years (as the least) to 15 (as the maximum). The prevalence of late menarche was 1.1%. In addition, no early menarche was reported. There was no relationship between menarche age and economic status, birth order and number of children, but a significant relationship was found between the parents' education, house status, and the lifestyle of parents.

CONCLUSION

The mean menarche age has been decreasing in cities. Therefore, it seems necessary for the families to be aware about the influence of time, trend and affecting factors on menarche; this helps them to make good decisions when educating their teenagers.

Nutritional Determinants of the Timing of Puberty

The timing of puberty has important public health, clinical, and social implications. The plasticity of sexual development onset could be a mechanism that adapts to prevailing environmental conditions. Early-life nutrition may provide cues for the environment's suitability for reproduction. This review focuses on recent developments in our understanding of the role of diet in the timing of sexual maturation. Population-based observational studies consistently indicate that childhood obesity is related to the earlier onset of puberty in girls. Similarly, intake of animal foods has been associated with earlier sexual development, whereas vegetable protein intake is related to delayed maturation. Evidence for prenatal nutrition, infant feeding practices, and childhood intake of fat, carbohydrate, and micronutrients is inconsistent. Secondary analyses of prenatal and early-life randomized nutritional interventions with extended follow-up through peripubertal years would help clarify the role of nutrition in the timing of sexual maturation.

Milk: an epigenetic amplifier of FTO-mediated transcription? Implications for Western diseases

Single-nucleotide polymorphisms within intron 1 of the FTO (fat mass and obesity-associated) gene are associated with enhanced FTO expression, increased body weight, obesity and type 2 diabetes mellitus (T2DM). The N⁶-methyladenosine (m⁶A) demethylase FTO plays a pivotal regulatory role for postnatal growth and energy expenditure. The purpose of this review is to provide translational evidence that links milk signaling with FTO-activated transcription of the milk recipient. FTO-dependent demethylation of m⁶A regulates mRNA splicing required for adipogenesis, increases the stability of mRNAs, and affects microRNA (miRNA) expression and miRNA biosynthesis. FTO senses branched-chain amino acids (BCAAs) and activates the nutrient sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), which plays a key role in translation. Milk provides abundant BCAAs and glutamine, critical components increasing FTO expression. CpG hypomethylation in the first intron of FTO has recently been associated with T2DM. CpG methylation is generally associated with gene silencing. In contrast, CpG demethylation generally increases transcription. DNA de novo methylation of CpG sites is facilitated by DNA methyltransferases (DNMT) 3A and 3B, whereas DNA maintenance methylation is controlled by DNMT1. MiRNA-29s target all DNMTs and thus reduce DNA CpG methylation. Cow´s milk provides substantial amounts of exosomal miRNA-29s that reach the systemic circulation and target mRNAs of the milk recipient. Via DNMT suppression, milk exosomal miRNA-29s may reduce the magnitude of FTO methylation, thereby epigenetically increasing FTO expression in the milk consumer. High lactation performance with increased milk yield has recently been associated with excessive miRNA-29 expression of dairy cow mammary epithelial cells (DCMECs). Notably, the galactopoietic hormone prolactin upregulates the transcription factor STAT3, which induces miRNA-29 expression. In a retrovirus-like manner milk exosomes may transfer DCMEC-derived miRNA-29s and bovine FTO mRNA to the milk consumer amplifying FTO expression. There is compelling evidence that obesity, T2DM, prostate and breast cancer, and neurodegenerative diseases are all associated with increased FTO expression. Maximization of lactation performance by veterinary medicine with enhanced miRNA-29s and FTO expression associated with increased exosomal miRNA-29 and FTO mRNA transfer to the milk consumer may represent key epigenetic mechanisms promoting FTO/mTORC1-mediated diseases of civilization.

Age at menarche and diet among adolescents in slums of Nashik, India

BACKGROUND AND AIM

The role of dietary patterns in determining age at menarche is insufficiently understood in low-income countries. The relationship between dietary patterns, particularly the consumption of oil, and age at menarche in a slum-dwelling adolescent population in India is examined.

METHODS

Data were derived from a cross-sectional baseline survey and anthropometric measurements among 10- to 19-year-old adolescents (n=545, female respondents 272, of whom 160 were post-menarcheal) and a household survey in two slums in the city of Nashik, Western India. By using mixed effects linear regression models, the association between age at menarche and household-wise use of sources of animal protein and oil and fat is examined.

RESULTS

Age at menarche (mean 13.7 years) in the slums studied was relatively high according to Indian standards. Age at menarche and the consumption of dairy products, meat, fish and eggs were not associated. The household per capita consumption of vegetable oil had an inverse association with a girl's age at menarche, and there was an indication of a positive association between use of ghee (clarified butter) and age at menarche. These associations did not disappear when controlling for anthropometric status and socio-economic characteristics.

CONCLUSION

Intake of fats and foods that are important sources of protein among underprivileged households in India is low and reflected in the relatively late age at menarche. The potential differences in the association between various types of fatty acids, energy intake and age at menarche in conditions of undernutrition requires further prospective study.

Milk Consumption after Age 9 Years Does Not Predict Age at Menarche

BACKGROUND

Regular milk consumption during childhood and adolescence is recommended for bone health. However, milk consumption increases circulating insulin-like growth factor I concentrations, and may also accelerate puberty.

OBJECTIVE

We prospectively investigated the association between milk consumption and age at menarche in the Growing Up Today Study.

METHODS

Study participants were 5583 US girls who were premenarcheal and ages 9-14 y in 1996. Girls were followed through 2001, at which time 97% of noncensored participants had reported menarche. Frequency of milk and meat consumption was calculated with the use of annual youth/adolescent food frequency questionnaires from 1996-1998. Intake of related nutrients was also measured. Age at menarche was self-reported annually through 2001.

RESULTS

During follow-up, 5227 girls attained menarche over 10,555 accrued person-years. In models adjusted for dietary and sociodemographic predictors of menarche, frequency of milk consumption did not predict age at onset of menarche (for >3 glasses of milk/d vs. 1.1-4 glasses/wk, HR: 0.93; 95% CI: 0.83, 1.04). After additional adjustment for body size, premenarcheal girls consuming >3 glasses of milk daily were 13% less likely (95% CI: -3%, -23%; P-trend: <0.01) to attain menarche in the next month relative to those consuming 1.1-4 glasses/wk. Neither total meat nor red meat consumption was associated with age at menarche.

CONCLUSIONS

Our findings suggest that regular consumption of milk in girls aged ≥9 y is unlikely to substantially affect age at onset of menarche. Studies assessing associations between diet in early childhood and pubertal timing may be more illuminating.

Milk--A Nutrient System of Mammalian Evolution Promoting mTORC1-Dependent Translation

Based on own translational research of the biochemical and hormonal effects of cow's milk consumption in humans, this review presents milk as a signaling system of mammalian evolution that activates the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), the pivotal regulator of translation. Milk, a mammary gland-derived secretory product, is required for species-specific gene-nutrient interactions that promote appropriate growth and development of the newborn mammal. This signaling system is highly conserved and tightly controlled by the lactation genome. Milk is sufficient to activate mTORC1, the crucial regulator of protein, lipid, and nucleotide synthesis orchestrating anabolism, cell growth and proliferation. To fulfill its mTORC1-activating function, milk delivers four key metabolic messengers: (1) essential branched-chain amino acids (BCAAs); (2) glutamine; (3) palmitic acid; and (4) bioactive exosomal microRNAs, which in a synergistical fashion promote mTORC1-dependent translation. In all mammals except Neolithic humans, postnatal activation of mTORC1 by milk intake is restricted to the postnatal lactation period. It is of critical concern that persistent hyperactivation of mTORC1 is associated with aging and the development of age-related disorders such as obesity, type 2 diabetes mellitus, cancer, and neurodegenerative diseases. Persistent mTORC1 activation promotes endoplasmic reticulum (ER) stress and drives an aimless quasi-program, which promotes aging and age-related diseases.

Higher Childhood Red Meat Intake Frequency Is Associated with Earlier Age at Menarche

BACKGROUND

Early age at menarche is associated with increased breast cancer risk. Red meat consumption in adolescence predicts breast cancer risk, but it is unknown whether it is also related to earlier menarche.

OBJECTIVE

We studied the association between intake of red meat at ages 5-12 y and age at menarche in a prospective study.

METHODS

We assessed usual diets with a food-frequency questionnaire in a group of 456 girls aged 8.4 ± 1.7 y and followed them for a median 5.6 y in Bogotá, Colombia. Girls were asked periodically about the occurrence and date of menarche. Median age at menarche was estimated with use of Kaplan-Meier survival probabilities by categories of red meat intake frequency. Cox proportional hazards models were used to compare the incidence of menarche by red meat intake frequency, adjusting for potential sociodemographic and dietary confounders including total energy intake and intake frequency of other animal food groups (dairy, poultry, freshwater fish, tuna/sardines, eggs, and innards).

RESULTS

Median age at menarche was 12.4 y. After adjustment for total energy intake, maternal parity, and socioeconomic status, red meat intake frequency was inversely associated with age at menarche. When compared with girls with red meat intake <4 times/wk, those consuming it ≥2 times/d had a significantly earlier age at menarche (HR: 1.64; 95% CI: 1.11, 2.41; P-trend = 0.0009). Incidentally, we found that girls with tuna/sardine intake >1 time/wk had a significantly later age at menarche (HR: 0.62; 95% CI: 0.42, 0.90; P = 0.01) than those with intake <1 time/mo. Intake frequency of other animal food groups was not significantly associated with age at menarche.

CONCLUSION

Higher red meat intake frequency during childhood is associated with an earlier age at menarche, whereas greater fatty fish intake frequency is associated with a later menarcheal age.

The pathogenic role of persistent milk signaling in mTORC1- and milk-microRNA-driven type 2 diabetes mellitus

Milk, the secretory product of the lactation genome, promotes growth of the newborn mammal. Milk delivers insulinotropic amino acids, thus maintains a molecular crosstalk with the pancreatic β-cell of the milk recipient. Homeostasis of β-cells and insulin production depend on the appropriate magnitude of mTORC1 signaling. mTORC1 is activated by branched-chain amino acids (BCAAs), glutamine, and palmitic acid, abundant nutrient signals of cow´s milk. Furthermore, milk delivers bioactive exosomal microRNAs. After milk consumption, bovine microRNA-29b, a member of the diabetogenic microRNA-29- family, reaches the systemic circulation and the cells of the milk consumer. MicroRNA-29b downregulates branchedchain α-ketoacid dehydrogenase, a potential explanation for increased BCAA serum levels, the metabolic signature of insulin resistance and type 2 diabetes mellitus (T2DM). In non-obese diabetic mice, microRNA-29b downregulates the antiapoptotic protein Mcl-1, which leads to early β-cell death. In all mammals except Neolithic humans, milk-driven mTORC1 signaling is physiologically restricted to the postnatal period. In contrast, chronic hyperactivated mTORC1 signaling has been associated with the development of age-related diseases of civilization including T2DM. Notably, chronic hyperactivation of mTORC1 enhances endoplasmic reticulum stress that promotes apoptosis. In fact, hyperactivated β-cell mTORC1 signaling induced early β-cell apoptosis in a mouse model. The EPIC-InterAct Study demonstrated an association between milk consumption and T2DM in France, Italy, United Kingdom, Germany, and Sweden. In contrast, fermented milk products and cheese exhibit an inverse correlation. Since the early 1950´s, refrigeration technology allowed widespread consumption of fresh pasteurized milk, which facilitates daily intake of bioactive bovine microRNAs. Persistent uptake of cow´s milk-derived microRNAs apparently transfers an overlooked epigenetic diabetogenic program that should not reach the human food chain.

Pubertal timing, bone acquisition, and risk of fracture throughout life

Pubertal maturation plays a fundamental role in bone acquisition. In retrospective epidemiological surveys in pre- and postmenopausal women, relatively later menarcheal age was associated with low bone mineral mass and increased risk of osteoporotic fracture. This association was usually ascribed to shorter time exposure to estrogen from the onset of pubertal maturation to peak bone mass attainment. Recent prospective studies in healthy children and adolescents do not corroborate the limited estrogen exposure hypothesis. In prepubertal girls who will experience later menarche, a reduced bone mineral density was observed before the onset of pubertal maturation, with no further accumulated deficit until peak bone mass attainment. In young adulthood, later menarche is associated with impaired microstructural bone components and reduced mechanical resistance. This intrinsic bone deficit can explain the fact that later menarche increases fracture risk during childhood and adolescence. In healthy individuals, both pubertal timing and bone development share several similar characteristics including wide physiological variability and strong effect of heritable factors but moderate influence of environmental determinants such as nutrition and physical activity. Several conditions modify pubertal timing and bone acquisition, a certain number of them acting in concert on both traits. Taken together, these facts should prompt the search for common genetic regulators of pubertal timing and bone acquisition. It should also open epigenetic investigation avenues to pinpoint which environmental exposure in fetal and infancy life, such as vitamin D, calcium, and/or protein supplies, influences both pubertal timing and bone acquisition.

Factors influencing menarcheal age: results from the cohort of tehran lipid and glucose study

BACKGROUND

Menarche is considered as a milestone in the women's reproductive life. Most existing studies on factors influencing menarcheal age had cross-sectional designs and their finding were controversial.

OBJECTIVES

We aimed to determine some factors affecting the age at menarche in a cohort study with an average of ten-year follow-up; the study was conducted within the framework of Tehran Lipid and Glucose Study (TLGS).

MATERIALS AND METHODS

For the purpose of the present study, we recruited all the females aged 12 to 18 years participated in TLGS whose menarche had not begun at the initiation of the study, but occurred during their follow-up. The effect of premenarcheal status of various factors including socioeconomic and anthropometric parameters, physical activity, energy expenditure, and exposure to tobacco smoke on menarcheal age was explored.

RESULTS

The mean of age at menarche was 13.06 ± 1.24 years. There were significant statistical associations between age of the participants' mothers at menarche (r = 0.66, P < 0.001), maternal education (r = -0.04, P = 0.002), and body mass index (BMI) before menarcheal (r = 0.25, P = 0.027) with age at menarche. There was no significant correlation between age at menarche, with either of maternal employment, premenarcheal physical activity, energy expenditure, and passive smoking.

CONCLUSIONS

Among various factor influencing menarcheal age, premenarcheal BMI is modifiable, and considering its significance, could prevent early or late menarches.