Can Nutrition Help in the Treatment of Infertility?

Comment on Aşır et al. Investigation of Vitamin D Levels in Men with Suspected Infertility. Life 2024, 14, 273

We have reviewed the article "Investigation of Vitamin D Levels in Men with Suspected Infertility" by Fırat Aşır [...].

Parental infertility and offspring cardiometabolic trajectories: a pooled analysis of three European cohorts

OBJECTIVE

To assess whether parental infertility is associated with differences in cardiometabolic trajectories in offspring.

DESIGN

Pooled observational analysis in three prospective cohorts.

SETTING

Three nationwide pregnancy cohorts.

PATIENTS

A total of 14,609 singletons from the UK Avon Longitudinal Study of Parents and Children, the Portuguese Geraçao 21, and the Amsterdam Born Children and Their Development study. Each cohort contributed data up to ages 26, 12, and 13 years, respectively.

INTERVENTION

Parental infertility is defined as time-to-pregnancy of ≥12 months (n = 1,392, 9.5%).

MAIN OUTCOME MEASURES

Trajectories of body mass index (BMI), waist circumference, systolic blood pressure, diastolic blood pressure, low-density lipoprotein cholesterol (LDL-C) level, high-density lipoprotein cholesterol (HDL-C) level, triglycerides level, and glucose level were compared in the offspring of couples with and without infertility. Trajectories were modeled using mixed-effects models with natural cubic splines adjusting for cohort, sex of the offspring, and maternal factors (age, BMI, smoking, educational level, parity, and ethnicity). Predicted levels of cardiometabolic traits up to 25 years of age were compared with parental infertility.

RESULTS

Offspring of couples with infertility had increasingly higher BMI (difference in mean predicted levels by age 25 years: 1.09 kg/m2, 95% confidence interval [0.68-1.50]) and suggestively higher diastolic blood pressure at age 25 years (1.21 mmHg [-0.003 to 2.43]). Their LDL-C tended to be higher, and their HDL-C values tended to be lower over time (age: 25 years, LDL-C: 4.07% [-0.79 to 8.93]; HDL-C: -2.78% [-6.99 to 1.43]). At age 17 years, offspring of couples with infertility had higher waist circumference (1.05 cm [0.11-1.99]) and systolic blood pressure (age: 17 years; 0.93 mmHg [0.044-1.81]), but these differences attenuated at later ages. No intergroup differences in triglyceride and glucose level trajectories were observed. Further adjustment for paternal age, BMI, smoking, and educational level, and both parents' histories of diabetes and hypertension in the cohort with this information available (Avon Longitudinal Study of Parents and Children) did not attenuate intergroup differences.

CONCLUSION

Offspring of couples with infertility relative to those of fertile couples have increasingly higher BMI over the years, suggestively higher blood pressure levels, and tend to have greater values of LDL-C and lower values of HDL-C with age.

Association between nutrient intake and female infertility: a study based on NHANES database

BACKGROUND

This study was designed to investigate the association between nutrients and female infertility.

METHODS

A cross-sectional study on 18-45 years of age reproductive-age women was conducted using the data from the National Health and Nutrition Examination Surveys (NHANES) for the periods 2013-2014 and 2015-2016. Multivariate logistic regression analysis was performed to evaluate the association between nutrients and female infertility. Subgroup analysis was applied to the body mass index (BMI). Results were summarised using an odds ratio (OR) with a 95% confidence interval (CI).

RESULTS

Of the total 1713 women, 204 women (11.91%) were infertile. The result demonstrated that higher intake of carbohydrate (OR: 0.46, 95% CI: 0.24-0.86, p = 0.018), vitamin A (OR: 0.44, 95% CI: 0.24-0.80, p = 0.009), vitamin C (OR: 0.48, 95% CI: 0.26-0.88, p = 0.020), magnesium (OR: 0.36, 95% CI: 0.17-0.76, p = 0.009), iron (OR: 0.43, 95% CI: 0.23-0.82, p = 0.012), lycopene (OR: 0.55, 95% CI: 0.33-0.91, p = 0.022), and total folate (OR: 0.38, 95% CI: 0.20-0.70, p = 0.003) were associated with a lower risk of female infertility. The subgroup analysis also reported that intakes of vitamin A, vitamin C, and lycopene were related to a lower risk of female infertility among women with a BMI being 18.5-24.9 kg/m2. Among women with BMI > 24.9 kg/m2, high intakes of magnesium, iron and total folate were associated with a decreased risk of female infertility.

CONCLUSIONS

The intake of several nutrients is associated with a decreased risk of female infertility. These findings provide insight into potentially modifiable lifestyle factors associated with female infertility.

Unraveling the Link Between Serum Homocysteine Levels and Nutrient Deficiency in Subfertility: A Comprehensive Review

Subfertility, a prevalent and emotionally taxing condition affecting couples worldwide, has garnered increasing attention in reproductive health. While its etiology remains multifaceted, emerging research has explored the role of serum homocysteine levels and nutrient deficiencies in influencing subfertility. This comprehensive review synthesizes current knowledge, beginning with an introduction to subfertility and the significance of investigating serum homocysteine levels. It proceeds to elucidate the role of nutrient deficiencies, particularly folate and vitamin B12, in homocysteine metabolism and examines existing research linking homocysteine to subfertility. The review explores potential mechanisms underlying this relationship, addressing the variability in study findings and their contributing factors. Implications for clinical practice, including assessing serum homocysteine levels, nutritional interventions, and personalized medicine, are discussed. Moreover, the review underscores the importance of ongoing research. It offers a call to action for advancing our understanding of subfertility and improving the lives of individuals and couples navigating reproduction challenges.

Oxidative Stress and Male Infertility: The Protective Role of Antioxidants

Oxidative stress is a significant factor in male infertility, compromising sperm function and overall reproductive health. As male infertility garners increasing attention, effective therapeutic interventions become paramount. This review investigates the therapeutic role of antioxidants in addressing male infertility. A detailed examination was conducted on antioxidants such as vitamin C, E, B12, D, coenzyme Q10, zinc, folic acid, selenium, l-carnitine, l-arginine, inositols, and alpha-lipoic acid. This analysis examines the methodologies, outcomes, and constraints of current clinical studies. Antioxidants show notable potential in counteracting the negative effects of oxidative stress on sperm. Based on the evidence, these antioxidants, individually or synergistically, can enhance sperm health and reproductive outcomes. However, certain limitations in the studies call for careful interpretation. Antioxidants are integral in tackling male infertility attributed to oxidative stress. The current findings underscore their therapeutic value, yet there's a pressing need for deeper, comprehensive research. Future studies should focus on refining dosage guidelines, identifying potential side effects, and discerning the most efficacious antioxidant combinations for male infertility solutions.

Glycemic index, glycemic load, dietary inflammatory index, and risk of infertility in women

The dietary glycemic load (GL) indicates the quantity and quality of carbohydrates, which can affect ovulation and fertility by controlling insulin sensitivity. Also, past studies confirm the role of the dietary inflammatory index (DII) in many diseases, including metabolic syndrome and cardiovascular disorders, so it may be related to reproductive health. This case-control study aims to study the association between glycemic index (GI), GL, and DII with infertility in women. This study was conducted on 300 infertile women in the case group and 300 fertile women in the control group in Kermanshah, Iran. Food intake was evaluated using FFQ, and using NUTRITIONIST IV software programs, GI and GL values were determined. DII was computed as well using FFQ data. Physical activity was assessed using IPAQ-SF. The association between GI, GL, and DII with infertility was evaluated using a logistic regression test, using STATA version 14 software. The results showed that the DII, GI, and GL were higher in the case group compared to the control group ([p = .009], [p = .0001], and [p = .0007], respectively). The increase in GI, GL, and DII caused an increase in infertility factors, and consequently enhanced chance of infertility ((adjusted odd ratio [OR] 2; 95% confidence interval [CI], 1.16, 3.45), (OR 3.68; 95% CI, 1.99, 6.82), and (OR 1.7; 95% CI, 0.97, 2.95), respectively). The present study indicated that the chance of infertility is higher in women who follow a diet with high GI, GL, and DII. Therefore, a positive association may be present between GI, GL, and DII with infertility.

Development of a nutrition screening tool to identify need for dietetic intervention in female infertility

BACKGROUND

One in seven couples are impacted by infertility in the UK, and female infertility is often associated with several health conditions impacted by nutrition. Despite many studies aimed at identifying the critical role of nutrition in infertility, there is currently no screening tool that identifies nutritional risk factors for infertility.

AIM

To propose a self-administered screening tool to identify women who would benefit from nutritional intervention to promote fertility.

METHODS

A narrative review was carried out to identify and summarise modifiable nutritional risk factors that can influence female fertility, including comorbidities that can influence nutrition intake, absorption, and metabolism.

KEY FINDINGS

A nutrition screening tool outlining modifiable nutrition risk factors potentially improving female fertility has been proposed, comprising of BMI, medical history and quality of diet and lifestyle which would aid in designing evidence based dietetic services for female infertility.

Does the Ketogenic Diet Improve the Quality of Ovarian Function in Obese Women?

Background: Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, the prevalence of which ranges from 8 to 13%. It is characterized by metabolic, reproductive, and psychological alterations. PCOS prevalence is related to body mass index (BMI). Women with BMI < 25 kg/m2 have a prevalence of 4.3%, whereas women with BMI > 30 kg/m2 have a prevalence of 14%. Moreover, women with PCOS have a risk of type 2 diabetes mellitus (T2DM) two-fold higher than controls, independently of BMI. Both PCOS and T2DM are also consequences of lower serum sex-hormone-binding globulin (SHBG) levels, which is currently considered a biomarker of metabolic disorders, in particular T2DM. Aim: To evaluate the effect of the very-low-calorie ketogenic diet (VLCKD) on markers suggested to be predictive of metabolic and ovulatory dysfunction. These comprehend SHBG, anti-Mullerian hormone (AMH), and progesterone levels on day 21 of the menstrual cycle in a cohort of obese non-diabetic women with PCOS and regular menses. Methods: Twenty-five patients (mean age 25.4 ± 3.44 years) with obesity and PCOS underwent VLCKD for 12 weeks. Each of them underwent measurements of anthropometric parameters (body weight, height, and waist circumference) and blood testing to evaluate serum levels of SHBG, AMH, and progesterone before and after 12 weeks of VLCKD. Results: At enrollment, all patients had high BMI, WC, and AMH, whereas SHBG and progesterone levels were low. After VLCKD, the patients showed a significant reduction in BMI, WC, and HOMA index. In particular, 76% of patients (19/25) switched from obesity to overweight, and the HOMA index normalized, reaching values lower than 2.5 in 96% (24/25) of patients. In addition, serum AMH levels significantly decreased, and progesterone and SHBG significantly increased after VLCKD. Conclusions: This is the first study documenting the effects of VLCKD on ovarian reserve and luteal function in women with PCOS. VLCKD could be used to improve metabolic and ovulatory dysfunction in women with PCOS. Further studies are needed to understand the reasons for the AMH reduction.

Health Related Behaviors and Life Satisfaction in Patients Undergoing Infertility Treatment

The aim of the study was to evaluate the level of life satisfaction and health behaviors presented by patients with diagnosed infertility. This cross-sectional study included 456 patients (235 women and 221 men) from infertile couples in southeastern Poland from June 2019 to February 2020. Participants completed a questionnaire on sociodemographic characteristics, the Health Behaviors Inventory (HBI), and the Satisfaction with Life Scale (SWLS). The average score of severity of health behaviors for the study group was 82.96 points. Satisfaction with life at a higher level was declared by 57.6% of respondents, at an average level was declared by 31.4%, and at a lower level was declared by 11%. The SWLS score for the entire study group was 24.11 points (6.82 points on the sten scale). Respondents who achieved a higher rate of life satisfaction also had a higher level of severity of health behaviors (p < 0.0001). There were no significant differences between male and female SWLS scores, although the women had significantly higher rates of severity of health behaviors than men. The level of health behavior is positively related to life satisfaction in infertile patients. Medical personnel should conduct health education on a healthy lifestyle that promotes the improvement of reproductive health.

Bovine In Vitro Oocyte Maturation and Embryo Production Used as a Model for Testing Endocrine Disrupting Chemicals Eliciting Female Reproductive Toxicity With Diethylstilbestrol as a Showcase Compound

Endocrine disrupting chemicals (EDCs) can interfere with normal hormonal action and regulation. Exposure of women to EDCs has been associated with adverse reproductive health outcomes. The assays currently used to identify EDCs that elicit female reproductive toxicity lack screening tests that address effects on the maturation of oocytes, a process that enables them to be fertilized and develop into embryos. Here, a screening method employing the bovine model of in vitro oocyte maturation and embryo production is described. Endpoints explored address important events in oocyte maturation and developmental competence acquisition. To test the method, the effects of the known human EDC diethylstilbestrol (DES; an estrogen receptor agonist) were evaluated in a range of concentrations (10^–9 M, 10^–7 M, 10^–5 M). Bovine oocytes were exposed to DES during in vitro maturation (IVM) or embryos were exposed during in vitro embryo culture (IVC). The endpoints evaluated included nuclear maturation, mitochondrial redistribution, cumulus cell expansion, apoptosis, and steroidogenesis. DES-exposed oocytes were fertilized to record embryo cleavage and blastocyst rates to uncover effects on developmental competence. Similarly, the development of embryos exposed to DES during IVC was monitored to assess the impact on early embryo development. Exposure to 10^–9 M or 10^–7 M DES did not affect the endpoints addressing oocyte maturation or embryo development. However, there were considerable detrimental effects observed in oocytes exposed to 10^–5 M DES. Specifically, compared to vehicle-treated oocytes, there was a statistically significant reduction in nuclear maturation (3% vs 84%), cumulus expansion (2.8-fold vs 3.6-fold) and blastocyst rate (3% vs 32%). Additionally, progesterone and pregnenolone concentrations measured in IVM culture media were increased. The screening method described here shows that bovine oocytes were sensitive to the action of this particular chemical (i.e., DES), albeit at high concentrations. In principle, this method provides a valuable tool to assess the oocyte maturation process and early embryo development that can be used for reproductive toxicity screening and possibly EDC identification. Further studies should include EDCs with different mechanisms of action and additional endpoints to further demonstrate the applicability of the bovine oocyte model for chemical risk assessment purposes and EDC identification.

Personalized Nutrition in the Management of Female Infertility: New Insights on Chronic Low-Grade Inflammation

Increasing evidence on the significance of nutrition in reproduction is emerging from both animal and human studies, suggesting a mutual association between nutrition and female fertility. Different “fertile” dietary patterns have been studied; however, in humans, conflicting results or weak correlations are often reported, probably because of the individual variations in genome, proteome, metabolome, and microbiome and the extent of exposure to different environmental conditions. In this scenario, “precision nutrition”, namely personalized dietary patterns based on deep phenotyping and on metabolomics, microbiome, and nutrigenetics of each case, might be more efficient for infertile patients than applying a generic nutritional approach. In this review, we report on new insights into the nutritional management of infertile patients, discussing the main nutrigenetic, nutrigenomic, and microbiomic aspects that should be investigated to achieve effective personalized nutritional interventions. Specifically, we will focus on the management of low-grade chronic inflammation, which is associated with several infertility-related diseases.

Reprotoxic Impact of Environment, Diet, and Behavior

Reproductive health is progressively declining due to multiples endogenous and exogenous factors, such as environmental contaminants, diet and behavior. Accumulated evidences confirm that fertility and reproductive function have been adversely affected by exposure to chemical contaminants released in the environment. Today, the impact of diet and behavior on reproductive processes is also receiving special attention from the scientific community. Indeed, a close relationship between diet and fertility has been proven. Furthermore, a combination of unhealthy behavior, such as exposure to hazardous compounds and stress factors, poses living organisms at higher risk of reprotoxic effects. In particular, it has been described that poor life behaviors are associated with reduced male and female fertility due to decreased gamete quality and function. Most of the erroneous behaviors are, furthermore, a source of oxidative stress that, leading to epigenetic alterations, results in an impaired reproductive fitness. This review reports the detrimental impact of the most common environmental chemical stressors, diet, and behavior on reproductive functionality and success. Although clear evidences are still scarce, reassuring data are provided that a healthy diet and reverting unhealthy lifestyles may be of help to recover physiological reproductive conditions.