Intake of dietary fibre and the age of menarche

The Impact of Macronutrient Intake on Sex Steroids During Onset of Puberty

INTRODUCTION

Increased fiber intake has been associated with decreased breast cancer risk, while increased animal protein intake with increased risk. The objective of this study is to examine the relationship of dietary fiber and protein intake to estrogen and sex hormone-binding globulin (SHBG) concentrations at puberty onset.

METHODS

These analyses were conducted using the Cincinnati puberty cohort of the Breast Cancer and the Environment Research Program, with girls followed every 6 months from ages 6 and 7. The analyses included serum measurements at 6-month intervals for estrogen and SHBG concentrations, from 18 months prior to breast stage 2 (onset of puberty). Dietary intake was documented via 24-hour dietary recalls every 3 months. Dietary factors of interest included total energy intake; total and animal protein; total, soluble, and insoluble fiber; and lignan and flavanol intake.

RESULTS

This study included 260 participants who generated 871 serum specimens and 3,000 days of diet intake. In longitudinal models, estradiol was associated inversely with insoluble fiber intake; estrone positively with animal protein intake; SHBG with greater insoluble fiber and lower total protein intake; and ratio of estrone to SHBG, a measure of bioavailable estrogen, positively with animal protein.

CONCLUSIONS

Greater protein intake, especially animal protein, led to greater estrogen concentrations and lower SHBG; greater animal protein and greater caloric intake led to increased bioavailable estrogen. This relationship may have served an evolutionary advantage in the past for greater fertility with adequate high-quality protein; in contemporary women, a modest decrease in animal protein may be beneficial in reducing breast cancer risk.

Nutrient Intake through Childhood and Early Menarche Onset in Girls: Systematic Review and Meta-Analysis

Among the genetic and environmental risk factors, nutrition plays a crucial role in determining the timing of puberty. Early menarche onset (EMO) is defined as when girls reach menarche onset at an age which is earlier than the mean/median age of menarche, between 12 and 13 years of age, according to individual ethnicity. The present study examined the association between nutrient intake in childhood and EMO risk in healthy girls by performing a systematic review and meta-analysis of prospective studies. We screened EMBASE, Cochrane Library, PubMed/MEDLINE, and Web of Science databases for 16 eligible studies with all medium-to-high quality scores ranging from 3 to 5 of 6 possible points with 10,884 subjects. Higher intakes of energy (risk ratio (RR) = 3.32, 95% confidence interval (CI) = 1.74–6.34, I² = 97%), and protein (RR = 3.15, 95% CI = 2.87–3.44, I² = 0%) were associated with EMO risk. For each additional 1 g/day animal protein intake in childhood, the age at menarche was approximately two months earlier (β = −0.13, I² = 55%), and high iron intake was associated with EMO (RR = 1.20, 95% CI = 1.03–1.40, I² = 0%). Polyunsaturated fatty acid (PUFAs) intake was associated with EMO risk with a dose-response effect (RR = 1.25, 95% CI = 1.05–1.49, I² = 44%). Girls with a high intake of fiber and monosaturated fatty acids (MUFAs) in childhood experienced later menarche onset (RR = 0.83, 95% CI = 0.69–1.00, I² = 31%; RR = 0.66, 95% CI = 0.50–0.86, I² = 0%, respectively). Thus, adherence to a high intake of animal proteins-, iron- and PUFA-rich food diet makes girls more likely to have EMO, while a high intake of fiber- and MUFA-rich foods may protect girls from EMO. Further studies are expected to investigate the role of specific types of PUFAs and MUFAs on EMO to promote healthy sexual maturity in girls.

Gendered division of labor in a Celtic community? A comparison of sex differences in entheseal changes and long bone shape and robusticity in the pre-Roman population of Verona (Italy, third-first century BC)

OBJECTIVES

The presence of a gendered subdivision of labor has been bioarchaeologically investigated in various prehistoric and historical contexts. Little is known, however, about the type of differences in daily activities characterizing men and women among the Celtic communities of Italy. The focus of the present study is the analysis of differences in patterns of entheseal changes (ECs) and long bone shape and robusticity between sexes among the Cenomani Gauls of Seminario Vescovile (SV-Verona, Italy, third-first century BC).

MATERIALS AND METHODS

The sample includes 56 adult individuals (22 females and 34 males). Presence of ECs on nine bilateral postcranial attachment sites, and values of humeral and femoral shape and robusticity indices based on external measurements were compared between sexes by means of generalized linear models and Mann-Whitney tests.

RESULTS

Results show a lack of difference between sexes in long bone shape and robusticity, and a higher incidence of upper and, especially, lower limb ECs in males.

DISCUSSION

These results suggest the presence of sex-specific activities at SV mostly related to farming and differently influencing the considered variables. Also, this study suggests the relevance of a series of nonbiomechanical factors (developmental, hormonal, genetic, and methodological) when attempting biocultural reconstructions from osteoarchaeological samples.

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.

Nongenetic determinants of age at menarche: a systematic review

BACKGROUND

The acceleration of pubertal development is an important medical and social problem, as it may result in increased morbidity and mortality in later life. This systematic review summarizes relevant data about nongenetic factors, which contribute to age at menarche (AAM), and suggests those which may be the most important.

METHODS

The available literature from 1980 till July 2013 was searched using PubMed and Google Scholar databases. Finally, 154 papers were selected for the analysis.

RESULTS

Environmental factors, which may affect AAM, vary in populations of different ethnicity. The prenatal, infancy, and early childhood periods are the most susceptible to these factors. Body weight, high animal protein intake, family stressors (e.g., single parenting), and physical activity seem to influence AAM in most populations.

CONCLUSIONS

The data about influence of nongenetic factors on AAM are still inconsistent. The factors affecting prenatal and early childhood growth seem to have a larger effect on further sexual maturation. Further studies are needed in order to validate the association between other environmental determinants and AAM in different ethnical groups.

Relation of isoflavones and fiber intake in childhood to the timing of puberty

BACKGROUND

It has been suggested that phytoestrogens and dietary fiber can affect puberty timing.

OBJECTIVE

We examined whether intake of isoflavone and fiber in healthy white children before their pubertal growth spurt [age at take-off (ATO)] was associated with puberty timing.

DESIGN

Multivariate regression analyses were performed in 227 DONALD (DOrtmund Nutritional and Anthropometric Longitudinally Designed) Study participants with 3-d weighed dietary records and information on potential confounders at baseline (1 and 2 y before ATO). In a subsample (n = 111), urinary isoflavones were determined in 24-h urine samples by gas chromatography-mass spectrometry analysis. Puberty timing was examined by using ATO and chronologic ages at pubertal stage 2 for breast development (B2) or gonadal development, peak height velocity (PHV), and menarche or voice break.

RESULTS

Girls whose diet was in the highest dietary isoflavone tertile experienced Tanner stage 2 for breast development ap 0.7 y later and reached PHV ap 0.6 y later than did girls whose diet was in the lowest isoflavone tertile [age (95% CI) at B2: 10.7 y (10.4, 10.9 y) compared with 10.0 y ( 9.7, 10.3 y), respectively; P for trend = 0.04; age at PHV: 11.9 y (11.6, 12.2 y) compared with 11.3 y (11.0, 11.6 y), respectively; P for trend = 0.04; adjusted for body mass index z score and fiber intake]. In boys, dietary isoflavones were not associated with pubertal markers. Urinary isoflavone and dietary fiber intakes were not associated with pubertal markers.

CONCLUSIONS

Girls, but not boys, with higher prepubertal isoflavone intakes appear to enter puberty at a later age. Fiber intake in this sample of healthy white girls and boys was not relevant for puberty timing.

Dietary patterns are associated with sexual maturation in Korean children

The purpose of this study was to investigate the association between dietary patterns and sexual maturation among Korean children. A cross-sectional study was conducted in 422 boys and 365 girls aged 9–12 years living in Seoul, Korea. Three-day food records were obtained, and pubertal stages were determined with a questionnaire using Tanner stages. Body fat was measured by bioelectrical impedance analysis, and bone mass content at the right calcaneus was measured by portable dual-emission X-ray absorptiometry. Exploratory factor analysis with a Varimax rotation was applied to identify dietary patterns using twenty-four food groups. Four distinct dietary patterns – ‘rice and Kimchi’, ‘shellfish and processed meat’, ‘pizza and drinks’ and ‘milk and cereal’ – were obtained. Twenty-six per cent (24% stage 2, 2% stage 3) of boys had genital development, and 79% (63% stage 2, 16% stage 3) of girls showed breast development. In boys, genital development was weakly positively associated with ‘shellfish and processed meat’ dietary factor scores (odds ratio 1·65, CI 0·95, 2·89,pfor trend 0·07) after adjusting for confounders. In girls, breast development was significantly positively associated with the factor score of ‘shellfish and processed meat’ (odds ratio 1·88, CI 1·08, 3·26,pfor trend 0·05). These results suggest that dietary patterns were related to body composition and sexual maturation among the Korean children. Further investigations are needed to identify components of the foods consumed in high amounts in these patterns and how they are related to sexual maturation.

Hormonal aspects in the causation of human breast cancer: epidemiological hypotheses reviewed, with special reference to nutritional status and first pregnancy

Epidemiology of breast cancer has identified early age at menarche, late first pregnancy, low parity and late menopause as risk factors, but in addition genetic factors, height, weight and living in western countries play a significant role. The international variation in incidence is almost exclusively due to non-genetic factors. Hypotheses in prevention-oriented research are reviewed: 1. obesity-related oestrogen production as a stimulus of the tumour in postmenopausal women; 2. nutritional status and energy expenditure during puberty and adolescence, developed for fertility and fecundity and extended later to breast cancer; 3. reproductive life during early adulthood, age at first pregnancy and its specific effects on breast tissues. The message of preventability of breast cancer is that mammary epithelial differentiation should come early. Our insight concerning events in puberty and early adulthood can be consolidated in one concept on the risk of extended proliferation of breast epithelium during early adulthood in the absence of full differentiation induced by pregnancy. The combined effects of Western-type nutrition, lack of exercise and Western-type women's emancipation sets the stage for breast cancer already at a young age. Since it is unlikely that emancipated women in affluent societies will return to the original life-style of getting pregnant as soon as it is biologically possible, a novel daring way of protection has to be considered. Could a "Breast Differentiation Pill" be developed to offer protection?

Timing of pubertal maturation in girls: an integrated life history approach

Life history theory provides a metatheoretical framework for the study of pubertal timing from an evolutionary-developmental perspective. The current article reviews 5 middle-level theories--energetics theory, stress-suppression theory, psychosocial acceleration theory, paternal investment theory, and child development theory--each of which applies the basic assumptions of life history theory to the question of environmental influences on timing of puberty in girls. These theories converge in their conceptualization of pubertal timing as responsive to ecological conditions but diverge in their conceptualization of (a) the nature, extent, and direction of environmental influences and (b) the effects of pubertal timing on other reproductive variables. Competing hypotheses derived from the 5 perspectives are evaluated. An extension of W. T. Boyce and B. J. Ellis's (in press) theory of stress reactivity is proposed to account for both inhibiting and accelerating effects of psychosocial stress on timing of pubertal development. This review highlights the multiplicity of (often unrecognized) perspectives guiding research, raises challenges to virtually all of these, and presents an alternative framework in an effort to move research forward in this arena of multidisciplinary inquiry.

Hyperinsulinemic diseases of civilization: more than just Syndrome X

Compensatory hyperinsulinemia stemming from peripheral insulin resistance is a well-recognized metabolic disturbance that is at the root cause of diseases and maladies of Syndrome X (hypertension, type 2 diabetes, dyslipidemia, coronary artery disease, obesity, abnormal glucose tolerance). Abnormalities of fibrinolysis and hyperuricemia also appear to be members of the cluster of illnesses comprising Syndrome X. Insulin is a well-established growth-promoting hormone, and recent evidence indicates that hyperinsulinemia causes a shift in a number of endocrine pathways that may favor unregulated tissue growth leading to additional illnesses. Specifically, hyperinsulinemia elevates serum concentrations of free insulin-like growth factor-1 (IGF-1) and androgens, while simultaneously reducing insulin-like growth factor-binding protein 3 (IGFBP-3) and sex hormone-binding globulin (SHBG). Since IGFBP-3 is a ligand for the nuclear retinoid X receptor alpha, insulin-mediated reductions in IGFBP-3 may also influence transcription of anti-proliferative genes normally activated by the body's endogenous retinoids. These endocrine shifts alter cellular proliferation and growth in a variety of tissues, the clinical course of which may promote acne, early menarche, certain epithelial cell carcinomas, increased stature, myopia, cutaneous papillomas (skin tags), acanthosis nigricans, polycystic ovary syndrome (PCOS) and male vertex balding. Consequently, these illnesses and conditions may, in part, have hyperinsulinemia at their root cause and therefore should be classified among the diseases of Syndrome X.

An evolutionary analysis of the aetiology and pathogenesis of juvenile-onset myopia

The available evidence suggests that both genes and environment play a crucial role in the development of juvenile-onset myopia. When the human visual system is examined from an evolutionary perspective, it becomes apparent that humans, living in the original environmental niche for which our species is genetically adapted (as hunter-gatherers), are either slightly hypermetropic or emmetropic and rarely develop myopia. Myopia occurs when novel environmental conditions associated with modern civilization are introduced into the hunter-gatherer lifestyle. The excessive near work of reading is most frequently cited as the main environmental stressor underlying the development of myopia. In this review we point out how a previously unrecognized diet-related malady (chronic hyperinsulinaemia) may play a key role in the pathogenesis of juvenile-onset myopia because of its interaction with hormonal regulation of vitreal chamber growth.

A cohort study of dietary fibre intake and menarche

OBJECTIVE

To evaluate the influence of dietary fibre on menarche in a cohort of pre-menarcheal girls.

DESIGN

Prospective cohort study.

SETTING

Ontario, Canada.

SUBJECTS

Free-living pre-menarcheal girls (n = 637), 6 to 14 years of age.

METHODOLOGY

Information on dietary intake, physical activity and date of menarche was collected at baseline and was updated annually by self-administered questionnaires for three years. Cox proportional hazards models were used to evaluate the association between dietary fibre and menarche, adjusting for age at entry to the study and potential confounders.

RESULTS

A higher intake of energy-adjusted dietary fibre was associated with a lower risk of (i.e. a later age at) menarche (relative hazard 0.54, 95% confidence interval (CI) 0.31-0.94 for highest vs. lowest quartile, P for trend = 0.027). At the fibre component level, a higher intake of energy-adjusted cellulose was associated with a lower risk of menarche (relative hazard 0.45, 95% CI 0.26-0.76, P for trend = 0.009).

CONCLUSIONS

The findings are consistent with the hypothesis that pre-menarcheal dietary intake can influence menarche.

Phyto-oestrogens: where are we now?

Phyto-oestrogens have emerged from their esoteric role in animal husbandry following the hypothesis that the human Western diet is relatively deficient in these substances compared with societies where large amounts of plant foods and legumes are eaten. Evidence is beginning to accrue that they may begin to offer protection against a wide range of human conditions, including breast, bowel, prostate and other cancers, cardiovascular disease, brain function, alcohol abuse, osteoporosis and menopausal symptoms. Of the two main classes of these weak oestrogens, the isoflavones are under intensive investigation due to their high levels in soyabean. Like the 'anti-oestrogen' Tamoxifen, these seem to have oestrogenic effects in human subjects in the cardiovascular system and bone. Although previously only available from food, isoflavones are now being marketed in health-food supplements or drinks, and tablets may soon be available over the counter as 'natural' hormone-replacement therapy. In cancer, anti-oestrogenic effects are thought to be important, although genistein especially has been shown to induce wide-ranging anti-cancer effects in cell lines independent of any hormone-related influence. There are few indications of harmful effects at present, although possible proliferative effects have been reported. In infants, the effects of high levels in soya milk formulas are uncertain. The second group, lignans, have been less investigated despite their known antioestrogenic effects and more widespread occurrence in foods. Investigation of the possible benefits of phyto-oestrogens is hampered by lack of analytical standards and, hence, inadequate methods for the measurement of low levels in most foods. This problem may prove to be a major dilemma for regulatory authorities, clinicians and others wishing to advise the general public on whether these compounds really do have the health benefits attributed to them.

Menarcheal age of school girls in the city of Jeddah, Saudia Arabia

In 1995 a survey was conducted in four schools in the city of Jeddah to determine the age of menarche in this population. Nine hundred and twenty-nine girls were studied. The mean age at menarche was 15.1 years, and this was later than most other Arabic countries and most Western countries, Social class was found to influence age at menarche, but the differences in relation to family size did not reach statistical significance. The reason for differences between population is discussed.

The effect of wartime conditions and the 1944-45 'Dutch famine' on recalled menarcheal age in participants of the DOM breast cancer screening project

In a retrospective cohort study on 21,067 women who participated in the DOM project, a breast cancer screening programme, age at menarche was studied in relation to the 'Dutch Famine' at the end of the Second World War. Menarche showed a delay during the entire war period, disrupting a secular trend pattern in both urban and rural areas. This delay could be explained by circumstances of general dearth and food rationing. The data did not show a clear effect of famine exposure over and above effects related to the entire war period. Where age at menarche is a risk factor for breast cancer, effects due to a modest limitation of caloric intake such as accomplished by the food rationing may be more relevant as to its public health impact on cancer risk reduction than any additional effects due to outright starvation as occurred during the 'hungerwinter'.

Diet and age at menarche

Early menarche has been associated with higher risk of breast cancer. A prospective study has been conducted in Quebec City, Canada, to evaluate the relationship of dietary intake to age at menarche. On three occasions during the schoolyear 1986-87, 2,299 pre-menarche. Incidence density ratios (IDRs) adjusted for age at entry and mothers' age at menarche were computed using proportional hazards models. IDRs for quartiles of energy, nutrient and food-group intakes were not different from the null value. In this population of well-nourished girls, diet did not influence the age at onset of menarche.