Female infertility and diet, is there a role for a personalized nutritional approach in assisted reproductive technologies? A Narrative Review

Dietary phytosterols induce infertility in female mice via epigenomic modulations

Dietary modifications to overcome infertility have attracted attention; however, scientifically substantiated information on specific dietary components affecting fertility and their mechanisms is limited. Herein, we investigated diet-induced, reversible infertility in female mice lacking the heterodimer of ATP-binding cassette transporters G5 and G8 (ABCG5/G8), which functions as a lipid exporter in the intestine. We found that dietary phytosterols, especially β-sitosterol and brassicasterol, which are substrates of ABCG5/G8, have potent but reversible reproductive toxicities in mice. Mechanistically, these phytosterols inhibited ovarian folliculogenesis and reduced egg quality by enhancing polycomb repressive complex 2-mediated histone H3 trimethylation at lysine 27 in the ovary. Clinical analyses showed that serum phytosterol levels were significantly and negatively correlated with the blastocyst development rate of fertilized eggs in women undergoing in vitro fertilization, suggesting that phytosterols affect egg quality in both humans and mice. Thus, avoiding excessive intake of certain phytosterols would be beneficial for female reproductive health.

Riboflavin for women's health and emerging microbiome strategies

Riboflavin (vitamin B2) is an essential water-soluble vitamin that serves as a precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). FMN and FAD are coenzymes involved in key enzymatic reactions in energy metabolism, biosynthesis, detoxification and electron scavenging pathways. Riboflavin deficiency is prevalent worldwide and impacts women's health due to riboflavin demands linked to urogenital and reproductive health, hormonal fluctuations during the menstrual cycle, pregnancy, and breastfeeding. Innovative functional foods and nutraceuticals are increasingly developed to meet women's riboflavin needs to supplement dietary sources. An emerging and particularly promising strategy is the administration of riboflavin-producing lactic acid bacteria, combining the health benefits of riboflavin with those of probiotics and in situ riboflavin production. Specific taxa of lactobacilli are of particular interest for women, because of the crucial role of Lactobacillus species in the vagina and the documented health effects of other Lactobacillaceae taxa in the gut and on the skin. In this narrative review, we synthesize the underlying molecular mechanisms and clinical benefits of riboflavin intake for women's health, and evaluate the synergistic potential of riboflavin-producing lactobacilli and other microbiota.

Dietary Inflammatory Index and female infertility: findings from NHANES survey

Background and objectives

Infertility is a pressing public health concern on a national scale and has been linked to inflammatory conditions. However, limited research has been conducted on the impact of the Dietary Inflammatory Index (DII) on female infertility. This study sought to investigate the association between DII and infertility utilizing data from the National Health and Nutrition Examination Survey (NHANES).

Methods

This cross-sectional study included a cohort of 3,071 women aged 20-44 years from three NHANES cycles (2013-2018). Dietary information was collected to calculate the Dietary Inflammatory Index (DII), while infertility status was determined through positive responses to specific questions in a questionnaire. The association between DII scores and infertility was assessed using adjusted multivariate logistic regression analyses. Subgroup analysis and restricted cubic spline (RCS) was conducted for further investigation.

Results

Among the participants, 354 women (11.53%) were identified as experiencing infertility. Upon adjusting for all covariates, a positive correlation was observed (OR = 1.61, 95% CI: 1.12-2.31). Individuals with DII scores in the highest quartile exhibited significantly greater odds of infertility compared to those in the lowest quartile (OR = 1.71, 95% CI = 1.17-2.51). The relationship between DII and infertility in the RCS models demonstrated an S-shaped curve. When using the median DII as a reference point, a higher DII was associated with an increased prevalence of infertility. Additionally, obesity was found to be a significant factor.

Conclusions

Our research indicated that the DII was positively correlated with an increased likelihood of infertility in American women among the ages of 20 and 44. These results contribute to the existing literature and underscore the need for further validation through larger prospective cohort studies.

Association between oxidative balance score and female infertility from the national health and nutrition examination survey 2013-2018

Background

The correlation between oxidative stress and female infertility pathogenesis was established, and the oxidative balance score (OBS) can serve as a measure of overall oxidative stress burden within an individual. Prior reports have not addressed the relationship between OBS and female infertility. This study endeavors to investigate the association between infertility risk in female and OBS.

Methods

The analysis focused on data from the National Health and Nutrition Examination Survey 2013-2018. OBS was determined from 16 dietary components and 4 lifestyle components. Multivariate logistic regression was employed to investigate the relationship between OBS and female infertility. Further stratified analysis was conducted to examine the associations across various subgroups. To elucidate the dose-response relationship between infertility risk in female and OBS, a restricted cubic spline function was employed.

Results

The study included a total of 1410 participants. Through weighted multivariable logistic regression analysis, we observed a consistent inverse correlation between OBS and the risk of female infertility [OR (95% CI) = 0.97 (0.95, 0.99), p = 0.047]. When participants were segregated into quartiles based on OBS, those in the highest quartile had a 61% [OR (95% CI) = 0.39 (0.2, 0.79), p = 0.01] reduced risk of infertility compared to those in the lowest quartile of OBS. A trend test assessing OBS by quartile also revealed the relationship between OBS and female infertility. This correlation remained constant across both dietary and lifestyle OBS. Additionally, lifestyle OBS and female infertility exhibited a nonlinear association. A sensitivity analysis verified the consistency of our findings.

Conclusion

The study found that a higher OBS is associated with a lower prevalence of female infertility. These results emphasized the potential role of oxidative homeostasis in the pathogenesis of infertility and highlighted the importance of follow-up studies and prevention strategies.

Examining the Role of Nutrition in Cancer Survivorship and Female Fertility: A Narrative Review

Female cancer survivors have a higher chance of experiencing infertility than females without a history of cancer diagnosis. This risk remains high despite advances in fertility treatments. There is a need to augment fertility treatments with cost-effective methods such as nutritional guidance to improve fertility chances. The aim of this review article is to connect the current literature on cancer survivorship nutrition and fertility nutrition, focusing on the importance of integrating nutritional guidance into fertility counseling, assessment, and treatment for female cancer survivors. Consuming a healthful diet comprising whole grains, soy, fruits, vegetables, seafood, and unsaturated fats has improved both female fertility and cancer survivorship. Similarly, maintaining a healthy body weight also improves female fertility and cancer survivorship. Therefore, dietary interventions to support female cancer survivors with fertility challenges are of immense importance. The period of follow-up fertility counseling and assessment after cancer treatment may provide a unique opportunity for implementing nutritional guidance for female cancer survivors. Dietary interventions are a promising strategy to improve pregnancy chances and overall quality of life among female cancer survivors; thus, researchers should investigate perceptions regarding fertility, barriers, and challenges to changing nutrition-related behaviors, and preferences for nutritional guidance to support fertility treatments in this population.

Dietary Patterns and Fertility

Diet has a key role in the reproductive axis both in males and females. This review aims to analyze the impacts of different dietary patterns on fertility. It appears that the Mediterranean diet has a predominantly protective role against infertility, while the Western diet seems to be a risk factor for infertility. Moreover, we focus attention also on dietary patterns in different countries of the World (Middle Eastern diet, Asian diet). In particular, when analyzing single nutrients, a diet rich in saturated fatty acids, cholesterol, animal proteins, and carbohydrates with high glycemic index is highly associated with male and female infertility. Finally, we evaluate the effects of vegetarian, vegan, and ketogenic diets on fertility, which seem to be still unclear. We believe that comprehension of the molecular mechanisms involved in infertility will lead to more effective and targeted treatments for infertile couples.

The Promise of Precision Nutrition for Modulation of the Gut Microbiota as a Novel Therapeutic Approach to Acute Graft-versus-host Disease

Acute graft-versus-host disease (aGVHD) is a severe side effect of allogeneic hematopoietic stem cell transplantation (aHSCT) that has complex phenotypes and often unpredictable outcomes. The current management is not always able to prevent aGVHD. A neglected actor in the management of aGVHD is the gut microbiota. Gut microbiota dysbiosis after aHSCT is caused by many factors and may contribute to the development of aGVHD. Diet and nutritional status modify the gut microbiota and a wide range of products are now available to manipulate the gut microbiota (pro-, pre-, and postbiotics). New investigations are testing the effect of probiotics and nutritional supplements in both animal models and human studies, with encouraging results. In this review, we summarize the most recent literature about the probiotics and nutritional factors able to modulate the gut microbiota and we discuss the future perspective in developing new integrative therapeutic approaches to reducing the risk of graft-versus-host disease in patients undergoing aHSCT.

Burden of female infertility in China from 1990 to 2019: a temporal trend analysis and forecasting, and comparison with the global level

BACKGROUND

Infertility is a common reproductive disease that affects not only individuals and families, but also the growth of the social population. Hence, understanding the burden of female infertility in China and worldwide is of great significance for the development of infertility prevention and treatment strategies.

METHODS

The Global Burden of Disease Study (GBD 2019) Data Resources were used to collect and collate relevant data on female infertility in China and worldwide from 1990 to 2019. The difference in the number, age-standardised prevalence rate (ASPR), disability-adjusted life years and age-standardised disability-adjusted life years rate (ASDR) of women with infertility in different periods and geographical areas were analysed. The autoregressive integrated moving average method was used to predict the ASPR and ASDR of female infertility in China and worldwide in the next 11years.

RESULTS

In the past 30years, the number of female infertility cases increased by 7.06million in China and 56.71million worldwide. The corresponding average annual increase of ASPR was 10.10% and 7.28%, respectively, and that of ASDR was 0.08% and 0.79%, respectively. In addition, there are differences in age and time between Chinese and global female infertility. In 1990, the crude prevalence rate of female infertility was the highest in women aged 40-44years and 35-39years in China and worldwide, respectively. In 2019, the crude prevalence rate of female infertility was still the highest in women aged 40-44years in China, whereas that around the world reached the highest in women aged 30-34years, which was significantly earlier. The forecast for the next 11years suggests that the ASPR and ASDR for female infertility in China will first rise and then decline, but the overall magnitude of change is not very significant, whereas the ASPR and ASDR for female infertility globally are still on the rise. The ASPR value of female infertility is expected to be 5025.56 in 100 000 persons in China and 3725.51 in 100 000 persons worldwide by 2030. The ASDR value of female infertility is expected to be 26.16 in 100 000 persons in China and 19.96 in 100 000 persons worldwide by 2030.

CONCLUSION

The burden of female infertility is still increasing in China and worldwide. Therefore, it is of great significance to pay more attention to infertile women, and advocate a healthy lifestyle to reduce the burden of disease for infertile women.

Insulin-like growth factor (IGF) performance in ovarian function and applications in reproductive biotechnologies

The role of the insulin-like growth factor (IGF) system has attracted close attention. The activity of IGF binding proteins (IGFBPs) within the ovary has not been fully elucidated to date. These proteins bind to IGF with an equal, or greater, affinity than to the IGF1 receptor, thus being in the main position to regulate IGF signalling, in addition to extending the half-life of IGFs within the bloodstream and promoting IGF storage in specific tissue niches. IGF1 has an important part in cell proliferation, differentiation and apoptosis. Considering the importance of IGFs in oocyte maturation, this review sought to elucidate aspects including: IGF production mechanisms; constituent members of their family and their respective functions; the role that these factors play during folliculogenesis, together with their functions during oocyte maturation and apoptosis, and their performance during luteal development. This review also explores the role of IGFs in biotechnological applications, focusing specifically on animal genetic gain.

Endocrine factors associated with infertility in women: an updated review

INTRODUCTION

Infertility is defined as the inability to conceive after unprotected sexual intercourse for at least 12 consecutive months. Our objective is to present an updated narrative review on the endocrine causes of infertility in women.

AREAS COVERED

A comprehensive review was conducted using Scielo, Scopus, and EMBASE databases, comprising 245 articles. The pathophysiology of infertility in women was described, including endocrinopathies such as hypothalamic amenorrhea, hyperprolactinemia, polycystic ovary syndrome, primary ovarian insufficiency, obesity, thyroid dysfunction, and adrenal disorders. The diagnostic approach was outlined, emphasizing the necessity of hormonal studies and ovarian response assessments. Additionally, the treatment plan was presented, commencing with non-pharmacological interventions, encompassing the adoption of a Mediterranean diet, vitamin supplementation, moderate exercise, and maintaining a healthy weight. Subsequently, pharmacological treatment was discussed, focusing on the management of associated endocrine disorders and ovulatory dysfunction.

EXPERT OPINION

This comprehensive review highlights the impact of endocrine disorders on fertility in women, providing diagnostic and therapeutic algorithms. Despite remaining knowledge gaps that hinder more effective treatments, ongoing research and advancements show promise for improved fertility success rates within the next five years. Enhanced comprehension of the pathophysiology behind endocrine causes and the progress in genetic research will facilitate the delivery of personalized treatments, thus enhancing fertility rates.