Prospective association of dietary soy and fibre intake with puberty timing: a cohort study among Chinese children

Associations of physical activity and soybean product consumption with psychological symptoms: a cross-sectional survey of Chinese university students

INTRODUCTION

Declining physical activity among university students has become a concern, with increasingly poor dietary behaviors and other unfavorable factors having an impact on the occurrence of psychological symptoms. Previous studies have analyzed the association between moderate-to-vigorous physical activity (MVPA) and psychological symptoms, but few studies have investigated the association between soy product consumption and these symptoms. In addition, the associations between physical activity and soy product consumption with psychological symptoms have not been investigated.

METHODS

In this study, 7267 university students from different regions of China were surveyed regarding physical activity, soy product consumption, and psychological symptoms. Binary logistic regression was used to analyze the associations among MVPA, soy product consumption, and psychological symptoms. A generalized linear model (GLM) was applied to further analyze the associations of MVPA and soy product consumption with psychological symptoms in this population.

RESULTS

The detection rate of psychological symptoms among Chinese university students was 17.9%, with the rate among female students (18.9%) higher than that among male students (16.6%). The proportion of university students with MVPA < 30 min/d, 30-60 min/d, and > 60 min/d was 76.1%, 19.3%, and 4.6%, respectively, and the proportion with soy product consumption ≤ 2 times/wk, 3-5 times/wk, and ≥ 5 times/wk was 25.8%, 42.4%, and 31.7%, respectively. The GLM showed that compared with university students who had MVPA < 30 min/d and soy product consumption ≤ 2 times/week, those with the lowest risk of developing psychological symptoms had MVPA > 60 min/d and soy product consumption ≥ 6 times/week (OR = 0.198, 95% CI: 0.100-0.393, P < 0.001). This group was followed by university students with MVPA > 60 min/d and soy product consumption 3-5 times/week (OR = 0.221, 95% CI: 0.102-0.479, P < 0.001).

CONCLUSION

In terms of research, there is an association between physical activity and soy product consumption and psychological symptoms among university students. The results of our study suggest that integrated intervention for psychological symptoms among university students is needed from the perspectives of physical activity and dietary behavior to promote good mental health in this population.

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.

Plant-Based Diet during the Prepubertal Period and Age at Menarche: A Systematic Review

This systematic review aimed to analyze the effect of a prepubertal plant-based diet, through dietary patterns and its nutritional components, on the age at menarche. Systematic searches through Medline (EBSCO), Embase, Health & Medical Collection (Proquest), Scopus, and Google Scholar for articles published between January 2000 and September 2022 in English using the keywords of plant-based diet, age at menarche, and their synonyms identified 673 articles. Articles were screened through titles and abstracts, as well as full-text reviews based on inclusion/exclusion criteria and assessment of research quality using the JBI Critical Appraisal Tools with a JBI cut-off final score of >50%, leaving 12 articles in this systematic review presented in the PRISMA 2020 flowchart. Data analysis was conducted descriptively by comparing findings between articles. Age at menarche/puberty was reported as an outcome of food intake through a vegetarian diet, Mediterranean diet, vegetable protein, phytoestrogens and isoflavones, and dietary fiber. Based on the analysis of each subgroup, the plant-based diet did not consistently influence the incidence of menarche. In conclusion, a plant-based diet does not significantly affect age at menarche when it is accompanied by a balanced intake of energy and macro-micronutrients. The principles of balanced nutrition and the assistance of nutritionists are needed in practicing a plant-based lifestyle, especially for children and adolescents who are still in the developmental stage.

Intervention Effect of Probiotics on the Early Onset of Puberty Induced by Daidzein in Female Mice

BACKGROUND

The relationship between soy isoflavones (SI)-induced gut dysbiosis and puberty onset has not been explored, and the protective effect of probiotic is still controversial. This study investigates the action of daidzein (the main components of SI) and probiotic on the age of puberty onset in female mice.

METHODS AND RESULTS

Changes in the gut microbiota and production of short chain fatty acids (SCFAs) metabolism are highlighted to analyze a possible causative relationship to puberty onset in female c57/bl mice. The results demonstrate that daidzein promotes earlier onset of puberty, and can significantly alter the composition of the fecal bacterial community. Furthermore, daidzein alters the gut microbiota such that levels of butyrate, isovalerate, and hexanoate are reduced. Moreover, a probiotic treatment normalizes the timing of puberty onset, likely due to alteration in the gut microbiota to enhance SCFAs production.

CONCLUSION

These findings provide evidence that 95% daidzein has the potential to advance the timing of puberty onset in female mice, and the gut microbiome can be a therapeutic target to regulate the timing of puberty onset.

Phytoestrogens and Health Effects

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

Impact of Physiologically Relevant Genistein Exposure at Different Time Windows on Puberty Onset and Neuroendocrine Function in Female Rats

SCOPE

Puberty timing, critical for adulthood wellbeing, is influenced by the environment, life-style, and diets. However, differential puberty-interfering effects of soy and soy isoflavone are observed in both epidemiological and toxicological studies. Additionally, their impact on neuroendocrine function at various pre-pubertal developmental windows is unclear.

METHODS AND RESULTS

This study investigates the effect of genistein, a typical soy isoflavone, at neonatal, lactational, and post-weaning stages on the time of vaginal opening and determines the levels of neuroendocrine factors in female rats using immunofluorescence, immunochemistry, and enzyme-linked immunosorbent assays. A physiologically relevant dosage (10 mg kg^-1 ) is used to resemble human exposure. The results show that genistein exposure at lactational stage significantly accelerates vaginal opening time, marginally increases hypothalamic gonadotropin-releasing hormone (GnRH) secretion, significantly enhances kisspeptin receptor expression, and markedly elevates blood levels of GnRH, luteinizing hormone, and follicle-stimulating hormone, while neonatal and post-weaning exposures do not induce significant alternations.

CONCLUSION

Lactational stage may be an important window for genistein to impact reproductive development and neuroendocrine regulations.

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.

Consumption of soy isoflavones during the prepubertal phase delays puberty and causes hypergonadotropic hypogonadism with disruption of hypothalamic-pituitary gonadotropins regulation in male rats

Isoflavones are phytoestrogens with recognized estrogenic activity but may also affect testosterone, corticosterone and thyroid hormone levels in experimental models. However, the molecular mechanisms involved in these alterations are still unclear. Isoflavones are present in soy-based infant formula, in breast milk after the consumption of soy by the mother and are widely used for the preparation of beverages consumed by toddlers and teenagers. In this sense, we proposed to investigate the effects of soy isoflavone exposure during the prepubertal period, a recognized window of sensitivity for endocrine disruption, over the hypothalamic-pituitary-testicular (HPT) axis. For this, 42 3-week-old male Wistar rats were exposed to 0.5, 5 or 50 mg of soy isoflavones/kg from postnatal day (PND) 23 to PND60. We evaluated body growth, age at puberty, serum concentrations of LH, FSH, testosterone and estradiol, and the expression of the transcripts (mRNA) of genes encoding key genes controlling the hypothalamic-pituitary-testicular (HPT) axis. In the hypothalamus, we observed an increase in Esr1 mRNA expression (0.5 and 5 mg). In the pituitary, we observed an increase in Gnrhr mRNA expression (50 mg), a reduction in Lhb mRNA expression (0.5 mg), and a reduction in Ar mRNA expression. In the testis, we observed an increase in Lhcgr mRNA expression (50 mg) and a reduction in Star mRNA expression (0.5 and 5 mg). The serum levels of LH (5 and 50 mg) and FSH (0.5 mg) were increased, while testosterone and estradiol were reduced. Puberty was delayed in all groups. Taken together, these results suggest that prepubertal consumption of relevant levels of soy isoflavones disrupts the HPT axis, causing hypergonadotropic hypogonadism and altered expression levels of key genes regulating the axis.