Diet and fertility: a review

Intake of protein-rich foods in relation to outcomes of infertility treatment with assisted reproductive technologies

Background

Some dietary factors have been linked to outcomes of infertility treatment with assisted reproductive technology (ART), but the role of intake of meats and other protein-rich foods remains unclear.

Objective

The aim of this manuscript was to study the relation between preconception intake of meat and other protein-rich foods and outcomes of infertility treatment with ART.

Design

A total of 351 women enrolled in a prospective cohort at the Massachusetts General Hospital Fertility Center and underwent 598 ART cycles for infertility treatment. Meat intake was assessed with a validated food-frequency questionnaire, and ART outcomes were abstracted from electronic medical records. We estimated the associations between intake of protein-rich foods (meats, eggs, beans, nuts, and soy) and the outcome of live birth per initiated cycle using generalized linear mixed models.

Results

The average total meat intake was 1.2 servings/d, with most coming from poultry (35%), fish (25%), processed meat (22%), and red meat (17%). Fish intake was positively related to the proportion of cycles resulting in live birth. The multivariable-adjusted probabilities of live birth for women in increasing quartiles of fish intake were 34.2% (95% CI: 26.5%, 42.9%), 38.4% (95% CI: 30.3%, 47.3%), 44.7% (95% CI: 36.3%, 53.4%), and 47.7% (95% CI: 38.3%, 57.3%), respectively (P-trend = 0.04). In the estimated substitution analyses, the ORs of live birth associated with increasing fish intake by 2 servings/wk were 1.54 (95% CI: 1.14, 2.07) when fish replaced any other meat, 1.50 (95% CI: 1.13, 1.98) when fish replaced any other protein-rich food, and 1.64 (95% CI: 1.14, 2.35) when fish replaced processed meat.

Conclusions

Fish consumption is related to a higher probability of live birth following infertility treatment with ART. This trial was registered at clinicaltrials.gov as NCT00011713.

No independent associations between preconception paternal dietary patterns and embryonic growth; the Predict Study

BACKGROUND & AIM

Several studies show the importance of periconceptional maternal dietary patterns on human embryonic growth. Healthy paternal nutrition has been associated with better semen quality and fecundability, however, evidence on the impact on pregnancy outcome is limited. Therefore, the aim of this study was to investigate the association between preconception paternal dietary patterns and first trimester embryonic growth using the parameters longitudinal crown-rump length (CRL) and embryonic volume (EV).

METHODS

A total of 638 couples were enrolled in the Rotterdam Periconceptional Cohort and received longitudinal three dimensional transvaginal ultrasound scans from 7⁺⁰ up to 12⁺⁰ weeks of gestation. Virtual reality software was used to perform offline measurements of the embryonic CRL and EV. Food frequency questionnaires (FFQ) were used to estimate habitual food intake in couples. Principal component analysis (PCA) was performed to identify paternal and maternal dietary patterns. Linear mixed models adjusted for potential confounders were applied to analyze associations between paternal and maternal dietary patterns and embryonic growth parameters.

RESULTS

The paternal dietary patterns retrieved were identified as "Whole wheat grains and Vegetables", "Sauces and Snacks Refined Grains", "Fish and Legumes" and explained 27.5% of the total variance of the dietary intake. No significant additional effects, independent of maternal dietary patters and other maternal and paternal potential confounders, were shown of these paternal dietary patterns on embryonic growth in spontaneous or IVF/ICSI pregnancies.

CONCLUSION

No significant effects of paternal dietary patterns independent of maternal dietary patters and other parental potential confounders on embryonic growth parameters could be established in spontaneous or IVF/ICSI pregnancies. The biological importance of paternal nutrition on semen quality, however, supports the need of periconceptional tailored nutritional counselling of couples trying to conceive.

Association of GRP78 promoter polymorphisms and serum GRP78 level with risk of asthenozoospermia

PURPOSE

The aim of this study was undertaken to investigate the association of 78-kDa glucose-regulated protein (GRP78) gene promoter polymorphisms with risk of asthenozoospermia (AZS) men. In addition, we performed association analysis between GRP78 promoter mutations and serum GRP78 level in asthenozoospermia.

METHODS

The study population comprised 400 subjects with AZS patients and 400 healthy controls. We assessed GRP78 rs3216733, rs17840761, and rs17840762 polymorphisms by using Snapshot SNP genotyping assays; serum GRP78 level was measured by enzyme-linked immunosorbent assay (ELISA). Semen quality was assessed by computer-assisted semen analysis.

RESULTS

We found that rs3216733 was associated with increased risk of AZS (Gd vs. dd: adjusted OR = 1.42, 95% CI, 1.06-1.93, P = 0.020; Gd/GG vs. dd: adjusted OR = 1.43, 95% CI, 1.08-1.91, P = 0.013; G vs. d adjusted OR = 1.26, 95% CI, 1.03-1.56, P = 0.027). The haplotype analyses showed the frequency of G-C-C haplotype was significantly higher in AZS (P = 0.026). The percentage of progressive motility sperm was lower in the asthenozoospermic men with Gd and Gd/GG genotypes than dd genotype (P = 0.003). Moreover, the serum GRP78 levels were significantly lower in rs3216733 Gd/GG genotypes compared with the dd genotype (P < 0.001).

CONCLUSION

Our findings suggest that rs3216733 Gd/GG genotypes contribute to poor sperm motility, probably by decreasing the level of GRP78.

The Influence of Diet on Fertility and the Implications for Public Health Nutrition in the United States

Despite growing evidence of the impact of diet on human fertility, few studies have examined the public health implications of this association in the United States (U.S.). This narrative review summarizes current scientific evidence on associations between dietary intake and fertility, discusses challenges in the public health landscape surrounding infertility, and proposes evidence-based recommendations to address these issues. Diets high in unsaturated fats, whole grains, vegetables, and fish have been associated with improved fertility in both women and men. While current evidence on the role of dairy, alcohol, and caffeine is inconsistent, saturated fats, and sugar have been associated with poorer fertility outcomes in women and men. Furthermore, women and men with obesity [body mass index (BMI) ≥ 30 kg/m²] have a higher risk of infertility. This risk is extended to women who are underweight (BMI <20 kg/m²). Diet and BMI influence outcomes during clinical treatment for infertility. Further, women in the U.S. who belong to an underrepresented minority group, have low income, or have low educational attainment, have significantly higher rates of infertility outcomes as compared to women who are non-Hispanic white, have high income, or have high educational attainment. Given this, it may be prudent to integrate nutrition counseling into both clinical guidelines for infertility as well as national dietary guidelines for individuals of reproductive age. Further studies on diet and reproductive health may enhance our ability to improve existing fertility programs across the U.S. and to deliver tailored care to women and men within at-risk groups.

Therapeutic Role of Green Tea Polyphenols in Improving Fertility: A Review

Sperm cells are highly sensitive to reactive oxygen species (ROS), which are produced during cellular oxidation. In normal cell biology, ROS levels increase with a decreasing antioxidant response, resulting in oxidative stress which threatens sperm biology. Oxidative stress has numerous effects, including increased apoptosis, reduced motion parameters, and reduced sperm integrity. In this regard, green tea polyphenols (GrTPs) have been reported to possess properties that may increase the quality of male and female gametes, mostly via the capability of catechins to reduce ROS production. GrTPs have antioxidant properties that improve major semen parameters, such as sperm concentration, motility, morphology, DNA damage, fertility rate, and gamete quality. These unique properties of green tea catechins could improve reproductive health and represent an important study area. This exploratory review discusses the therapeutic effects of GrTPs against infertility, their possible mechanisms of action, and recommended supportive therapy for improving fertility in humans and in animals.