Sugar-sweetened beverage intake in relation to semen quality and reproductive hormone levels in young men

Whole tomato lipidic extract improved sperm quality in obese rats induced by a high-carbohydrate diet

BACKGROUND

Obesity represents a risk in the development of metabolic and oxidative stress (OS), as well as in male infertility. There is still no pharmacological treatment for obesity-induced male infertility, but the use of natural antioxidants has been proposed as a treatment.

OBJECTIVE

The aim of this work is to evaluate the effect of a whole tomato lipid extract on rats that decreased their fertility and spermatogenesis after being induced obese with a high carbohydrate diet.

MATERIALS AND METHODS

One hundred fourteen male Wistar rats of 12 weeks of age were used. Two groups were randomly formed non-obese control group (C, n = 54) and obese group (Ob, n = 54) that received 30% w/v sucrose solution for 3 months. Subsequently, the C and Ob group were divided into two groups: vehicle (C-Vh and Ob-Vh) that received corn oil as vehicle and tomato lipid extract (C-Ex and Ob-Ex) that received whole tomato lipid extract. The groups that received a hypercaloric diet had a gain in visceral and retroperitoneal adipose tissue, an increase in total cholesterol and triglyceride levels, increased OS in the testis, and lesions in testicular histology, as well as a reduction in testicular size and sperm quality parameters (motility, viability, and concentration).

RESULTS

Treatment with whole tomato lipid extract significantly decreased the weight of gonadal adipose tissue and OS, maintained testicular size, showed a significant increase in sperm quality parameters and improved histology of seminiferous tubules.

CONCLUSIONS

These results demonstrate a greater therapeutic and beneficial effect of the tomato lipid extract on sperm quality parameters in obese rats and therefore on fertility.

Longitudinal trends and correlation between autism spectrum disorder prevalence and sperm quality parameters (2000-2024): a comprehensive statistical analysis

Introduction

Over the past few decades, there has been growing concern about the concurrent trends of increasing Autism Spectrum Disorder (ASD) prevalence and declining sperm quality. These trends represent significant public health challenges that warrant thorough investigation of their underlying causes and implications.

Objectives

The primary objectives of this study are to analyze trends in ASD prevalence and sperm quality parameters from 2000 to 2024, assess the statistical significance and effect size of these trends, explore potential correlations between ASD prevalence and sperm quality parameters, and identify significant predictors among sperm quality parameters that influence ASD prevalence.

Methods

This study employed a longitudinal approach using multiple regression, time series analysis, ANOVA, Principal Component Analysis (PCA), hierarchical clustering, logistic regression, and cross-correlation analysis. Data on ASD prevalence were sourced from the CDC Autism and Developmental Disabilities Monitoring Network, while sperm quality data were collected from various published studies.

Results

The findings reveal significant negative associations between ASD prevalence and sperm quality parameters such as sperm concentration and motility, suggesting that better sperm quality is linked to lower ASD rates. Conversely, parameters like sperm DNA fragmentation (SDF), volume of ejaculate, pH level, and semen viscosity show positive associations with ASD prevalence, indicating higher values in these parameters correlate with higher ASD rates.

Conclusion

The study highlights the importance of maintaining reproductive health to potentially mitigate ASD risk and calls for further research to elucidate the underlying mechanisms driving these trends. These findings support the hypothesis that reproductive health factors play a crucial role in ASD etiology and suggest potential biological markers for assessing ASD risk.

Effect of perinatal consumption of low-calorie sweetener on maternal health: A systematic review and meta-analysis

BACKGROUND AND AIMS

Evidence regarding perinatal low-calorie (or artificial) sweetener (LCS) consumption and its effect on maternal health outcomes is limited and inconclusive. The primary outcomes of our systematic review and meta-analysis were the effect of preconception and pregnancy LCS exposure on reproductive and pregnancy outcomes. Secondary outcomes included long-term maternal health.

METHODS

A systematic search of electronic databases, including PubMed, Embase, CINAHL, the Cochrane Library, Scopus, Web of Science, PsycINFO, ProQuest Health and Medical, ClinicalTrials.gov and Google Scholar, was conducted up to 20 November 2023. Primary studies, including clinical trials, cohort studies, case-control studies, which reported any LCS consumption during perinatal period and pregnancy and maternal health outcomes were eligible. A random effects model with restricted maximum likelihood estimation was used for the meta-analysis. We appraised the quality of the included studies using the National Institute of Health study quality appraisal tool and the overall quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation tool.

RESULTS

A total of 19 eligible studies with 203,706 participants were included. LCS consumption during pregnancy was associated with 11% increased risk of preterm birth (RR = 1.11, 95% CI: 1.07-1.16, I2 = 0.01%) and 42% increased risk of gestational diabetes (RR = 1.42, 95% CI: 0.98-2.04, I2 = 67.60%) compared with no consumption, however, the effect size for gestational diabetes was not precise as the 95% CI indicated that the effect estimate could range from 2% lower risk to 204% (or 2.04 times) higher risk. We found no association between LCS consumption during pregnancy and gestational weight gain (standardized mean difference (SMD) = 0.04; 95% CI: -0.17 - 0.24, I2 = 41.31%) or gestational age at birth (SMD = 0.00; 95% CI: -0.13 - 0.14, I2 = 80.13%). The effect of LCS consumption on reproductive treatment outcomes were inconsistent.

CONCLUSIONS

Based on the evidence available, LCS consumption in pregnancy was associated with increased risk of preterm birth and gestational diabetes. Robust research, such as well-designed randomized trials and large prospective cohort studies, is required to confirm the causal effect of LCS consumption during perinatal period on adverse maternal health outcomes.

Do Popular Diets Impact Fertility?

Infertility affects 15% of the population in developed countries, and its prevalence is increasing. Fertility can be influenced by different factors. Although key factors like maternal age cannot be changed, there is growing evidence that other modifiable factors, such as diet, can have an impact on fertility. Diet has become increasingly important in recent years for a number of reasons: the new trend toward a healthy lifestyle, the higher prevalence of certain digestive disorders, a lack of time that leads people to consume more prepared and processed food, and personal choice to not eat meat, among others. To meet these needs, several diets have recently become popular, such as the Mediterranean diet, known as the gold standard of health; the DASH diet, known for preventing hypertension; the Western diet, characterized by processed food; the ketogenic diet, characterized by low carbohydrate intake; and the vegetarian diet, which is the choice for people who do not eat meat or animal by-products. Diets present a unique composition characterized by the presence or absence of specific nutrients, which have also been associated with male and female fertility individually. This review assesses the impact of these diets and of macro- and micronutrients on both female and male fertility.

Dietary Glycemic Index and Load and Semen Quality: A Cross-Sectional and Prospective Analysis within the FERTINUTS Trial

PURPOSE

Infertility is a global health issue and nutrition plays a significant role in fertility outcomes. We aimed to investigate the cross-sectional and prospective associations of glycemic index (GI) and glycemic load (GL) with semen quality parameters in a cohort of healthy young men.

MATERIALS AND METHODS

The study included 106 men aged 18-35 years from the FERTINUTS trial. Dietary intake was estimated through 3-day dietary records and several semen parameters were assessed. Multivariable linear regression analysis with the Least Absolute Shrinkage and Selection Operator (LASSO) approach was employed.

RESULTS

The cross-sectional analysis revealed positive associations between GI and GL and total sperm count, sperm concentration, and total motility. In the prospective analysis, baseline GI was associated with increases in pH, vitality, immotile sperm or abnormal midpiece and decreases in total sperm count and motility. Conversely, GL was positively associated with changes in vitality and total sperm count.

CONCLUSIONS

While these findings suggest that GI may have adverse effects on several sperm quality parameters, the results were not consistently observed in the cross-sectional analysis. However, GL was consistently associated with better sperm quality in both analyses. The impact of carbohydrate quality and quantity on fertility remains uncertain and larger prospective studies are needed.

A preconception cohort study of sugar-sweetened beverage consumption and semen quality

BACKGROUND

Dietary factors, including high sugar intake, may have adverse effects on male reproduction. Studies of the association between sugar-sweetened beverage (SSB) intake and semen quality have reported inconsistent results.

OBJECTIVE

We estimated the effects of SSB consumption on semen quality in a North American preconception cohort study.

METHODS

We analyzed baseline data from 690 males (n = 1,247 samples) participating in Pregnancy Study Online (PRESTO) during 2015-2022. Participants aged ≥21 years completed a baseline questionnaire on which they reported information about intake of SSBs, including sodas, energy drinks, sports drinks, and fruit juices. After enrollment, we invited U.S. participants to a semen testing substudy, in which they collected and analyzed two samples using an at-home semen testing kit. We used linear regression models to estimate adjusted percent differences (%D) and 95% confidence intervals (CI) for associations of SSB intake with semen volume, sperm concentration, total sperm count (TSC), motility, and total motile sperm count (TMSC). We used modified Poisson regression models to estimate adjusted risk ratios (RRs) and 95% CIs for the association of SSB intake with World Health Organization semen parameter cut points.

RESULTS

Relative to non-consumers of SSBs, those who consumed ≥7 SSBs/week had lower semen volume (%D = -6, 95% CI: -13, 0), sperm concentration (%D = -22, 95% CI: -38, 0), TSC (%D = -22, 95% CI: -38, -2), motility (%D = -4, 95% CI: -10, 2), and TMSC (%D = -25, 95% CI: -43, -2). High SSB consumers also had greater risks of low sperm concentration (≤16 million/mL; RR = 1.89, 95% CI: 1.11, 3.21), low TSC (≤39 million; RR = 1.75, 95% CI: 0.92, 3.33), low motility (≤42%; RR = 1.23, 95% CI: 0.87, 1.75) and low TMSC (≤21 million; RR = 1.95, 95% CI: 1.12, 3.38). Associations were stronger among participants with body mass index ≥ 25 kg/m2 .

CONCLUSION

Greater SSB consumption was associated with reduced semen quality in a North American preconception cohort.

Ultra-processed food consumption and semen quality parameters in the Led-Fertyl study

STUDY QUESTION

Is ultra-processed food (UPF) consumption associated with semen quality parameters?

SUMMARY ANSWER

Higher UPF consumption was inversely associated with total sperm count, sperm concentration, and total motility in men of reproductive age.

WHAT IS KNOWN ALREADY

The consumption of UPF, which has been rising during the last decades, has been demonstrated to be positively associated with several chronic diseases such as diabetes or cardiovascular diseases. However, the scientific evidence on its potential impact on semen quality remains notably limited.

STUDY DESIGN SIZE DURATION

A cross-sectional analysis was conducted using data from 200 healthy men (mean age 28.4 ± 5.5 years) enrolled in the Led-Fertyl (Lifestyle and Environmental Determinants of Seminogram and Other Male Fertility-Related Parameters) study between February 2021 and April 2023.

PARTICIPANTS/MATERIALS SETTING METHODS

UPF consumption (% of energy from UPF) was estimated according to the NOVA classification system using a validated 143-item semi-quantitative food frequency questionnaire. Total sperm count, sperm concentration, sperm vitality, total motility, progressive motility, and normal sperm forms were set as the main outcomes. Microscopic parameters were analyzed using a phase-contrast microscope and a computer-assisted sperm analysis (CASA) system. Semen samples were collected and tested according to World Health Organization 2010 standards. Multivariable linear regression models were fitted to estimate the associations between UPF tertile and semen quality parameters.

MAIN RESULTS AND THE ROLE OF CHANCE

Sperm concentration (β: -1.42 × 106 spz./ml; 95% CI: -2.72 to -0.12) and motility (β: -7.83%; 95% CI: -15.16 to -0.51) were lower in participants in the highest tertile of UPF compared to the lowest. A similar association was observed for sperm count when UPF was analyzed per 10% increment of energy from UPF consumption (β: -1.50 × 106 spz.; 95% CI: -2.83 to -0.17). Theoretically replacing 10% of energy from UPF consumption with 10% of energy from unprocessed or minimally processed food consumption was associated with a higher total sperm count, sperm concentration, total motility, progressive motility, and normal sperm forms.

LIMITATIONS REASONS FOR CAUTION

Cross-sectional studies do not permit the drawing of causal inferences. Measurement errors and reporting bias cannot be entirely ruled out.

WIDER IMPLICATIONS OF THE FINDINGS

This work suggests that consumption of UPF may have an impact on certain semen quality parameters. Furthermore, opting for unprocessed or minimally processed foods instead of UPFs could potentially benefit semen quality. If these results are replicated in future epidemiological studies with different long-term designs, these novel findings could provide valuable insights for updating or even designing preventive and interventional programs to address infertility among men of reproductive age.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by the Spanish government's official funding agency for biomedical research, ISCIII, through the Fondo de Investigación para la Salud (FIS), the European Union ERDF/ESF, 'A way to make Europe'/'Investing in your future' [PI21/01447], and the Diputació de Tarragona (2021/11-No.Exp. 8004330008-2021-0022642). J.S.-S. gratefully acknowledges the financial support of ICREA under the ICREA Academia program. C.V.-H. received a predoctoral grant from the Generalitat de Catalunya (2022 FI_B100108). M.Á.M. was supported by the Sara Borrell postdoctoral fellowship (CD21/00045-Instituto de Salud Carlos III (ISCIII)). M.F.d.l.P. was supported by a predoctoral grant from the Rovira i Virgili University and Diputació de Tarragona (2020-PMF-PIPF-8). All authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Dietary intervention in adult rats exposed to a high-sugar diet early in life permanently impairs sperm quality

Childhood obesity predicts the presence of adult obesity. Obesity is associated with poor sperm quality. We hypothesized that exposure to a high-sugar diet (HSD) in early life would cause permanent histomorphology damage to the testes, resulting in reduced sperm quality in adult life. Wistar rats (aged 21days) were divided into four groups (n=6). In the first experiment, the rats received tap water (control) and a 30% sucrose diet for two months (S30). In the second experiment, the control and 30% sucrose diets were fed for two months, followed by replacement with tap water for two months (IS30). Eating and drinking were monitored. Animals were then euthanized, visceral and gonadal fat tissue and testes were collected, and epididymal spermatozoa were excised. Testicular samples were used for morphological description by H&E staining and for quantifying triacylglycerol content, caspase activity, and oxidative stress. Serum testosterone concentration was evaluated. Spermatozoa were used to assess sperm quality. Our results show that sperm quality was impaired by consuming HSD and could not be restored by dietary intervention. HSD feeding induced hyperplasia of visceral adipose tissue, increased testicular weight, and serum testosterone levels. The dietary intervention increased visceral adipose tissue, serum, and testicular triacylglycerol levels and normalized serum testosterone levels. Overall, the HSD diet caused permanent changes in seminiferous tubule cross-sectional area, caspase activity, oxidative stress, and sperm quality. Therefore, a high-sugar diet in early life causes permanent damage to sperm quality in adulthood.

Diet and recreational drug use in relation to male reproductive health

Diet and lifestyle interventions present promising avenues for the improvement of male fertility. Our objective was to review and synthesize the existing observational and experimental studies among humans on the associations of diet and recreational drug use with semen quality and fertility outcomes. The available data on this topic are limited and, at times, conflicting. Nevertheless, on the basis of this review, dietary patterns that are composed of higher intakes of fruits, vegetables, whole grains, nuts, low-fat dairy, and seafood, as well as lower intakes of red and processed meats, sweets, and sugar-sweetened beverages were identified as having the strongest evidence for associations with better sperm quality. However, whether these dietary patterns translate into positive associations with clinical fertility endpoints such as assisted reproductive technology success rates or time-to-pregnancy among couples trying to conceive without medical assistance remains unclear. Male caffeine and alcohol intake, within low-to-moderate ranges of intake, do not appear to be detrimental to semen quality. Yet high-quality research on this topic, focused on clinical fertility endpoints, should continue given the conflicting evidence, particularly in populations undergoing infertility treatment with assisted reproductive technology. Recreational drug use, including marijuana, electronic cigarettes, and other illicit drugs, does not appear to be beneficial for male reproductive health and should be avoided or ceased. In conclusion, men should be encouraged to consume a healthy diet rich in fruits, vegetables, whole grains, nuts, low-fat dairy, and seafood, as well as lacking in red and processed meats, sweets, and sugar-sweetened beverages, and to avoid recreational drug use for improved male reproductive health.

Sweet Taste Receptor T1R3 Expressed in Leydig Cells Is Closely Related to Homeostasis of the Steroid Hormone Metabolism Profile

Taste receptor type 1 subunit 3 (T1R3) is initially expressed in mammal tongue for recognition and response of sweet/umami tastants and is critical to nutrient absorption, even endocrine. In this study, down-regulation of related steroidogenic enzymes such as StAR, 3β-HSD, CYP17A1, and 17β-HSD with the decrease of T1R3 expression was found in Leydig cells treated by a T1R3 inhibitor (lactisole). The abundances of progesterone, 17a-hydroxyprogesterone, androstenedione, testosterone, and deoxycorticosterone were down-regulated by 2.3, 3.5, 1.4, 1.6, and 2.2 times, respectively, after T1R3 inhibition. In addition, opposite results were found in saccharin sodium treatment. T1R3 activation contributed to intracellular cyclic adenosine monophosphate (cAMP) accumulation (14.41 ± 0.58 vs 20.21 ± 0.65) and increased testosterone (20.31 ± 3.49 vs 50.01 ± 7.44) and steroidogenic metabolite levels. Coadministration of human chorionic gonadotropin and saccharin sodium resulted in elevating the testosterone and cAMP levels and enhancing the expression levels of steroidogenic-related factors. Similarly, intratesticular injection of lactisole and saccharin sodium further confirmed that T1R3 inhibition/activation affected the expression of related steroidogenic enzymes and the testosterone levels in mice. The above findings suggest that T1R3 plays a role in testicular steroidogenesis.

Effectiveness of Nutritional Therapies in Male Factor Infertility Treatment: A Systematic Review and Network Meta-analysis

BACKGROUND

Nutritional therapies are effective alternative treatments for male infertility or subfertility. These are cost-effective and easily implementable, unlike other advanced invasive treatments. Even moderate improvements in sperm quality could improve spontaneous pregnancy.

OBJECTIVE

We aimed to compare the effectiveness of all nutritional therapies in male infertility/subfertility treatment and ranked their efficacy based on type and etiology. We intend to aid clinicians with an evidence-based approach to affordable and safer initial infertility treatment for those who mainly do not wish to have other advanced invasive treatments or could not afford or have access to them.

METHODS

We included 69 studies with 94 individual study arms identified from bibliographic databases and registries. We included studies in adult men with proven infertility or subfertility that investigated nutritional or dietary supplement therapies compared with control or placebo and at least reported on a sperm parameter. We undertook a network meta-analysis and performed a pairwise meta-analysis on all sperm parameter outcomes and meta-regression. No language or date restriction was imposed. A systematic article search was concluded on August 29, 2022.

RESULTS

Our network meta-analysis is the first to compare all dietary interventions in a single analysis, sub-grouped by intervention type and type of infertility. L-Carnitine with micronutrients, antioxidants, and several traditional herbal supplements showed statistically and clinically significant improvement in sperm quality. Meta-regression identified that improvement in the sperm count, motility and morphology translated into increased pregnancy rates (p < 0.001; p < 0.001; p < 0.002, respectively). In particular, L-carnitine with micronutrient therapy (risk ratio [RR]: 3.60, 95% CI 1.86, 6.98, p = 0.0002), followed by zinc (RR 5.39, 95% CI 1.26, 23.04, p = 0.02), significantly improved pregnancy rates. Men with oligozoospermia (RR 4.89), followed by oligoasthenozoospermia (RR 4.20) and asthenoteratozoospermia (RR 3.53), showed a significant increase in pregnancy rates.

CONCLUSION

We ranked nutritional therapies for their ability to improve sperm quality in men with infertility. Nutritional therapies, particularly L-carnitine alone or combined with micronutrients, significantly improved sperm parameters and pregnancy rates even under severe conditions. We believe these affordable solutions may be valuable for people without access to or who do not wish to undergo more invasive and costly fertility treatments.

The Influence of Metabolic Factors and Diet on Fertility

Infertility is a disease globally affecting 20-30% of the reproductive age female population. However, in up to 50% on recorded cases, problems with infertility are ascribed to men; therefore, it is important to popularize healthy eating also in this group. During the last decade, it has been observed that society's lifestyle changed drastically: reduced energy expenditure in physical activity per day, increased consumption of hypercaloric and high-glycemic-index foods with high content of trans fats, and reduced consumption of dietary fiber, which negatively affects fertility. Increasing evidence points to a link between diet and fertility. It is becoming clear that well-planned nutrition can also contribute to the effectiveness of ART. The low-GI plant-based diet appears to have a positive effect, especially when it is based on Mediterranean dietary patterns: rich in antioxidants, vegetable protein, fiber, MUFA fatty acids, omega-3, vitamins, and minerals. Importantly, this diet has been shown to protect against chronic diseases associated with oxidative stress, which also translates into pregnancy success. As lifestyle and nutrition seem to be important factors affecting fertility, it is worth expanding knowledge in this regard among couples trying to conceive a child.

Sugar-sweetened beverage intake in relation to reproductive parameters in young men

BACKGROUND

There has been a decrease in sperm concentration in recent years. Concurrently, there were important dietary changes, including an increase in sugar-sweetened beverage intake (SSB). The relation between SSB and male reproduction functions in humans are barely described in the literature.

METHODS

Cross-sectional study with 209 participants (18-23 years old) recruited during one year in Murcia, Spain. All men provided semen and blood samples the same day. SSB consumption was evaluated using a 101-item validated food frequency questionnaire. Reproductive hormones were analysed from serum samples, obtaining levels of follicle-stimulating hormone, inhibin B, luteinizing hormone, estradiol, and testosterone. The evaluation of semen analysis followed the WHO guidelines and consisted of seminal volume, sperm concentration, total sperm count, percentage of morphologically normal sperm, and percentage of motile sperm. SSB intake association with semen parameters and hormone levels were examined using multiple linear regression.

RESULTS

Men in the highest quartile of the SSB intake had a higher percentage of morphologically normal sperm, 37.4% [6.1, 68.3] (p, trend=0.047) and higher estradiol levels (9.5% [-3.5, 22.5] (p, trend=0.047) than those in the first quartile. SSB intake was unrelated to other semen quality parameters or reproductive hormone levels.

CONCLUSIONS

Our results indicate that sperm morphology and estradiol levels may be associated with sugar-sweetened beverage intake. These findings might be explained by physiological metabolism homeostasis, though more studies are required to confirm these results and draw conclusions in other male populations.

Effect of Stress and Caffeine on Male Infertility

Caffeine is a natural psychoactive chemical found in beverages made from coffee. In addition, it is added by the manufacturers of a large number of sodas and energy drinks. It does this by stimulating both the brain and the central nervous system, enabling you to avoid being sleepy while still keeping you attentive. A state of emotional or physical tension is defined as stress. It can be induced through the experience of something or thinking of something that causes you to feel uncomfortable, irritated, or nervous. Your body's response to adversity or demand is what we call stress. Among couples, male infertility is common. A failure in spermatogenesis is accountable for nearly half of all occurrences of infertility in marriage. Ageing, psychological stress, diet, physical exercise, coffee, hot water, hot scrotum, and cell phone usage are some of the few modifiable lifestyle variables that have a role in the development of infertility. Many hypotheses have been proposed to establish the link between stress in the workplace, life events (war, earthquake, etc.), and inability to conceive have been linked to inferior or degraded semen quality. In this review, we will discuss the effect on male fertility of elements including quality of life (such as exercise, diet, and other alterations to one's daily routine) and psychological stress. In addition, the effects on male fertility of elevated scrotal temperature, improper dietary habits, and physical inactivity will be discussed. The loss in male fertility, mainly due to ageing, inappropriate lifestyles, and environmental factors, is a significant public health concern in this century. Couples can enhance their quality of life and increase their chances of naturally conceiving a child by altering their way of life and supplementing it with nutraceutical antioxidants and an organised educational, environmental, dietary, and physical exercise program.

The Impact of Non-caloric Sweeteners on Male Fertility: A Systematic Review and Narrative Synthesis in Rodent Models

Understanding the factors which influence fertility is essential for developing appropriate nutritional recommendations for couples trying to conceive. Non-caloric sweeteners (NCS) are increasing in the food chain and despite being no/low calorie, several adverse metabolic consequences have been attributed to their consumption. Their effects on reproduction have been relatively under-researched, particularly in males. This review aims to systematically review the literature for evidence of the effect of NCS on male fertility in rodents, with sperm parameters (sperm quantity and quality) assessed as primary outcomes. Given the lack of information available in humans this review has been carried out using evidence from rodent models. Risk of bias assessment was carried out using the Syrcle risk of bias tool. Nine studies met the inclusion criteria. Forty-four percent showed a negative effect of NCS on male reproductive parameters compared with controls. The effects of NCS on fertility have been conflicting and selected studies have been heterogeneous in relation to study design. It is unclear if NCS has an impact on male reproductive function. There is a need for randomized controlled trials using a standardized protocol for analysis, to formulate a clear message in terms of male fertility.

Sugar Consumption Is Negatively Associated with Semen Quality

Recently, in parallel to decrease in semen quality, the consumption of sugar has risen sharply. This provided the rationale to study the association between whole dietary sugar consumption and semen quality. Our aim was to investigate the association between sugar consumption and semen quality. The final cross-sectional study population (n = 280 of initial n = 593, after applying inclusion and exclusion criteria) attending routine semen analysis at sperm bank laboratory was subject to semen quality analysis according to WHO criteria (volume, sperm concentration, total sperm count, percentage total motility, and percentage normal morphology) and filled food frequency questionnaire (FFQ) and lifestyle questionnaire. Associations between consumed sugars and semen quality were analyzed using multivariate regression adjusted to relevant cofounders for 2 food components containing sugar including soft drinks (SoftD) and total added sugar to food products (SugProd). We found negative association between higher consumption of dietary sugar in all 2 dietary sub-categories and sperm concentration. Significant sperm concentration decrements of 18% and 23% were associated with SoftD median consumption of 0.2 drinks/day (IQR; 0.1-0.5 drinks/day). Significant sperm concentration decrements of 15% and 17% were associated with median SugProd consumption of 25 teaspoons of added sugar/day (IQR; 19-31 teaspoons of added sugar/day). In conclusion, our study findings demonstrate that sugar consumption is negatively associated with sperm concentration.

Diet Quality Scores and Asthenoteratozoospermia Risk: Finding From a Hospital-Based Case–Control Study in China

Objective

We aimed to examine associations of diet quality scores, including the dietary approaches to stop hypertension (DASH), alternate Healthy Eating Index (AHEI), and Chinese Healthy Eating Index (CHEI) with asthenoteratozoospermia risk in China.

Methods

Among 254 cases and 633 controls in a hospital-based case–control study in Shenyang, Liaoning Province, China, DASH, AHEI, and CHEI were calculated using a validated food frequency questionnaire. Asthenotetrazoospermia was evaluated according to World Health Organization guidelines. Unconditional multiple logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between quality diet scores and asthenoteratozoospermia risk.

Results

We found that the CHEI score was inversely associated with asthenoteratozoospermia risk, with ORs of 0.59 (95% CI 0.39, 0.88) and 0.59 (95% CI 0.39, 0.88) for the 2nd and 3rd tertiles vs. the 1st tertile, respectively (P trend < 0.05). In addition, our data indicated that each standard deviation increase in CHEI, AHEI-2010, and DASH score was associated with 19, 13, and 17% decreased risk of asthenoteratozoospermia, respectively.

Conclusion

Our findings suggest that higher adherence to the CHEI, AHEI-2010, and DASH diet quality scores may reduce the risk of asthenoteratozoospermia, especially for younger participants.

Diet and Male Fertility: The Impact of Nutrients and Antioxidants on Sperm Energetic Metabolism

Diet might affect male reproductive potential, but the biochemical mechanisms involved in the modulation of sperm quality remain poorly understood. While a Western diet is considered a risk factor for male infertility, the Mediterranean diet seems to protect against male infertility; moreover, the role of a vegetarian habitus in the preservation of sperm quality is controversial. The aim of this review is to analyze the molecular effects of single nutrients on sperm quality, focusing on their involvement in biochemical mechanisms related to sperm bioenergetics. It appears that diets rich in saturated fatty acids (SFA) and low in polyunsaturated fatty acids (PUFA) negatively affect sperm quality, whereas unsaturated fatty acids supplementation ameliorates sperm quality. In fact, the administration of PUFA, especially omega-3 PUFA, determined an increase in mitochondrial energetic metabolism and a reduction in oxidative damage. Carbohydrates and proteins are also nutritional modulators of oxidative stress and testosterone levels, which are strictly linked to sperm mitochondrial function, a key element for sperm quality. Moreover, many dietary natural polyphenols differentially affect (positively or negatively) the mitochondrial function, depending on their concentration. We believe that an understanding of the biochemical mechanisms responsible for sperm quality will lead to more targeted and effective therapeutics for male infertility.

Consumption of Sugar-Sweetened or Artificially Sweetened Beverages and Semen Quality in Young Men: A Cross-Sectional Study

BACKGROUND

Existing literature suggests that frequent consumption of sugar-sweetened drinks may be associated with lower semen quality. Studies performed in mice suggest a dose-response relationship between intake of saccharin or aspartame, two artificial sweeteners, and sperm and testis function.

METHODS

A cross-sectional study based on data from The Fetal Programming of Semen Quality (FEPOS) Cohort, including 1047 young men (mean age = 19 years) was performed. Each male participant completed an online questionnaire on health, health behavior and diet, and provided a semen sample. The associations between consumption of sugar-sweetened or artificially sweetened beverages (moderate ≥ 3 days/week; infrequent < 3 days/week) and semen quality were analyzed using a multivariable, negative, binomial regression model.

RESULTS

Sugar-sweetened or artificially sweetened beverage consumption was not strongly associated with either semen volume, sperm concentration, total sperm count or total motility in young men. The proportion of morphologically normal sperm was 11% lower (0.89 (95% CI 0.76, 1.04)) for moderate (≥3 days/week) consumption of artificially sweetened beverages relative to infrequent (<3 days/week).

CONCLUSION

Consumption of sugar-sweetened or artificially sweetened beverages, at the levels present in this study had limited effect on the measured markers of semen quality in young men.

A dietary score representing the overall relation of men's diet with semen quality in relation to outcomes of infertility treatment with assisted reproduction

Objective

To examine the impact of men's diet on outcomes of infertility treatment with assisted reproductive technology (ART) using an empirical score representing the relation of diet with semen quality.

Design

Prospective cohort study.

Setting

Fertility center at an academic medical center.

Patients

We included 296 men (688 semen samples) to identify an empirical dietary pattern and 231 couples (406 ART cycles) to investigate the association of this diet pattern with ART outcomes.

Interventions

Men's diet was assessed at baseline using a validated questionnaire. An empirical dietary pattern reflecting the overall relation of diet with semen quality was identified using reduced rank regression.

Main Outcome Measures

The primary outcome was live birth per treatment cycle. The secondary outcomes were fertilization, implantation, and clinical pregnancy.

Results

Men had a median baseline age and body mass index of 36.8 years and 26.9 kg/m², respectively. Although the empirical diet pattern was significantly associated with all semen parameters, the empirical diet score was not related to any clinical outcome of infertility treatment after ART. The adjusted probabilities of relevant clinical outcomes in the lowest and highest quartiles of the empirical score were 0.62 (0.50-0.73) and 0.55 (0.45-0.66) for implantation, 0.57 (0.46-0.69) and 0.50 (0.40-0.61) for clinical pregnancy, and 0.49 (0.37-0.62) and 0.36 (0.25-0.48) for live birth. Analyses excluding couples with a diagnosis of male factor infertility and, separately, excluding intracytoplasmic sperm injection cycles yielded similar results.

Conclusions

A dietary score representing the overall association of diet with semen quality parameters was not associated with ART outcomes.

Association between intake of soft drinks and testicular function in young men

STUDY QUESTION

Is intake of sugar-sweetened beverages (SSB) or artificially sweetened beverages (ASB) associated with testicular function in young men?

SUMMARY ANSWER

Among young men unaware of their semen quality and reproductive hormone levels, intake of SSBs was associated with lower sperm concentration, lower total sperm count, and a lower ratio of serum inhibin-B/FSH.

WHAT IS KNOWN ALREADY

SSBs may adversely impact testicular function, but results are not consistent across studies. Moreover, the associations of ASB, energy-drinks or fruit juices with testicular function are unclear.

STUDY DESIGN, SIZE, DURATION

Young healthy men and unselected for fertility status men enrolled in a cross-sectional study between 2008 and 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 2935 young (median age: 19 years) men enrolled in the study. Intake of SSBs, ASBs, fruit juices, and energy-drinks was assessed with a validated food frequency questionnaire. Testicular function was assessed through conventional semen quality parameters (semen volume, sperm concentration, total count, motility and morphology), testicular volume assessed with ultrasound, and serum reproductive hormone concentrations (total testosterone, free testosterone, E2, inhibin-B, LH, FSH, sex hormone-binding globulin) were measured.

MAIN RESULTS AND THE ROLE OF CHANCE

In multivariable-adjusted analyses, men in the highest category of SSB intake (median: 1.1 servings (∼220 ml)/day) had a 13.2 million/ml lower median sperm concentration (95% CI: -21.0, -5.5) than non-consumers. A similar pattern was observed with total sperm count (-28 million (95% CI: -48, -9)), serum inhibin-B (-12 pg/ml (95% CI: -21, -4)), and inhibin-B/FSH ratio (-9 (95% CI: -18, 0)). The adjusted median difference in sperm concentration and inhibin-B associated with increasing SSB intake by 1 serving (∼200ml)/day at the expense of water was -3.4 million sperm/ml (95% CI: -5.8, -1.0) and -7 pg/ml (95% CI: -11, -3), respectively.

LIMITATIONS, REASONS FOR CAUTION

Inferring causality is limited owing to the cross-sectional design. We adjusted for a number of potential confounders but cannot exclude that unmeasured lifestyle and behavior associated with soft drink intake is associated with testicular function in these young men.

WIDER IMPLICATIONS OF THE FINDINGS

In the largest study to date, intake of SSBs was associated with lower sperm concentration, total sperm count, and serum inhibin-B/FSH ratio, consistent with a direct suppressive effect of SSB intake on testicular function among otherwise healthy men, potentially affecting fertility. However, the observed association between higher SSB intake and lower semen quality does not necessarily imply a decrease in fertility.

STUDY FUNDING/COMPETING INTEREST(S)

Supported by research from the Danish Council for Strategic Research (2101-08-0058), Independent Research Fund Denmark (8020-00218B), European Union (212844), the Kirsten and Freddy Johansen's Foundation (95-103-72087), the Research Fund of the Capital Region of Denmark (A6176), and the NIH (P30DK046200). The authors report no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

The relationship between major dietary patterns and fertility status in iranian men: a case-control study

In this case-control study, we aimed to investigate the association between major dietary patterns and fertility status in Iranian men. The study population included 400 newly diagnosed infertile men and 537 healthy individuals without a history of infertility in Yazd, Iran. Infertility was confirmed clinically, based on the World Health Organization (WHO) criteria. Dietary intake was assessed using a 168-item semi-quantitative food frequency questionnaire (FFQ), and dietary patterns were determined based on a principal component analysis. Four major dietary patterns were found in this study, including healthy, Western, mixed, and traditional dietary patterns. After adjustments for potential confounders, men above the median of a healthy dietary pattern showed a reduced risk of infertility compared to those below the median (OR 0.52; 95% CI 0.33-0.83). In contrast, men with greater adherence to Western and mixed dietary patterns were more likely to be infertile (OR 2.66; 95% CI 1.70-4.17 and OR 2.82; 95% CI 1.75-4.56, respectively). Also, there was no significant association between the traditional dietary pattern and the odds of infertility. The present study suggests that greater adherence to a healthy dietary pattern may have an inverse association with the odds of infertility; however, Western and mixed dietary patterns may be associated with an increased risk of infertility.

Maternal lifestyle and nutritional habits are associated with oocyte quality and ICSI clinical outcomes

RESEARCH QUESTION

Do maternal lifestyle factors influence the incidence of oocyte dimorphisms and outcomes of intracytoplasmic sperm injection (ICSI) cycles?

DESIGN

A total of 752 female patients undergoing an ICSI cycle at a private university-affiliated IVF centre from January 2015 to December 2019 were included in this historical cohort study. Before starting ovarian stimulation, participants completed a questionnaire on cigarette smoking habits, consumption of alcoholic beverages, refined sugar, artificial sweeteners, soft drinks, fruits, legumes and vegetables, milk and dairy, and meat, as well as exercise frequency over the past 6 months. Oocyte morphology was evaluated before ICSI. The influence of maternal lifestyle factors on the incidence of oocyte dimorphisms and ICSI outcomes was evaluated by multivariate general linear models and generalized linear models, adjusted for potential confounders. The main outcome measures were the incidence of oocyte dimorphisms per cycle and clinical outcomes.

RESULTS

Lifestyle factors and nutritional habits such as cigarette smoking, and the consumption of alcohol, refined sugar and artificial sweeteners, were positively associated with incidence of several oocyte dimorphisms and negatively associated with the response to ovarian stimulation and embryo development. Negative relationships were also observed between these habits and clinical outcomes, apart from miscarriage rate, in which positive relationships were observed. Significant negative dose-dependent relationships between these habits and implantation rates were noted (P < 0.001). Alcoholic beverage consumption also showed inverse dose-dependent relationships with clinical pregnancy and live birth rates. Live birth rate was also negatively associated with cigarette smoking, in a dose-dependent manner.

CONCLUSIONS

Poor maternal habits were associated with reduced oocyte quality and ICSI outcomes in this study. Many of these associations were shown to be dose-dependent.

Male cellular telephone exposure, fecundability, and semen quality: results from two preconception cohort studies

STUDY QUESTION

To what extent is exposure to cellular telephones associated with male fertility?

SUMMARY ANSWER

Overall, we found little association between carrying a cell phone in the front pants pocket and male fertility, although among leaner men (BMI <25 kg/m2), carrying a cell phone in the front pants pocket was associated with lower fecundability.

WHAT IS KNOWN ALREADY

Some studies have indicated that cell phone use is associated with poor semen quality, but the results are conflicting.

STUDY DESIGN, SIZE, DURATION

Two prospective preconception cohort studies were conducted with men in Denmark (n = 751) and in North America (n = 2349), enrolled and followed via the internet from 2012 to 2020.

PARTICIPANTS/MATERIALS, SETTING, METHODS

On the baseline questionnaire, males reported their hours/day of carrying a cell phone in different body locations. We ascertained time to pregnancy via bi-monthly follow-up questionnaires completed by the female partner for up to 12 months or until reported conception. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs) for the association between male cell phone habits and fecundability, focusing on front pants pocket exposure, within each cohort separately and pooling across the cohorts using a fixed-effect meta-analysis. In a subset of participants, we examined selected semen parameters (semen volume, sperm concentration and sperm motility) using a home-based semen testing kit.

MAIN RESULTS AND THE ROLE OF CHANCE

There was little overall association between carrying a cell phone in a front pants pocket and fecundability: the FR for any front pants pocket exposure versus none was 0.94 (95% CI: 0.0.83-1.05). We observed an inverse association between any front pants pocket exposure and fecundability among men whose BMI was <25 kg/m2 (FR = 0.72, 95% CI: 0.59-0.88) but little association among men whose BMI was ≥25 kg/m2 (FR = 1.05, 95% CI: 0.90-1.22). There were few consistent associations between cell phone exposure and semen volume, sperm concentration, or sperm motility.

LIMITATIONS, REASONS FOR CAUTION

Exposure to radiofrequency radiation from cell phones is subject to considerable non-differential misclassification, which would tend to attenuate the estimates for dichotomous comparisons and extreme exposure categories (e.g. exposure 8 vs. 0 h/day). Residual confounding by occupation or other unknown or poorly measured factors may also have affected the results.

WIDER IMPLICATIONS OF THE FINDINGS

Overall, there was little association between carrying one's phone in the front pants pocket and fecundability. There was a moderate inverse association between front pants pocket cell phone exposure and fecundability among men with BMI <25 kg/m2, but not among men with BMI ≥25 kg/m2. Although several previous studies have indicated associations between cell phone exposure and lower sperm motility, we found few consistent associations with any semen quality parameters.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the National Institutes of Health, grant number R03HD090315. In the last 3 years, PRESTO has received in-kind donations from Sandstone Diagnostics (for semen kits), Swiss Precision Diagnostics (home pregnancy tests), Kindara.com (fertility app), and FertilityFriend.com (fertility app). Dr. L.A.W. is a fibroid consultant for AbbVie, Inc. Dr. H.T.S. reports that the Department of Clinical Epidemiology is involved in studies with funding from various companies as research grants to and administered by Aarhus University. None of these studies are related to the current study. Dr. M.L.E. is an advisor to Sandstone Diagnostics, Ro, Dadi, Hannah, and Underdog. Dr. G.J.S. holds ownership in Sandstone Diagnostics Inc., developers of the Trak Male Fertility Testing System. In addition, Dr. G.J.S. has a patent pending related to Trak Male Fertility Testing System issued.

TRIAL REGISTRATION NUMBER

N/A.

Effects of Mediterranean diet on semen parameters in healthy young adults: a randomized controlled trial

BACKGROUND

Dietary regimens have so far been studied as possible determinants of semen quality and fertility. The aim of this study was to evaluate the effects of a Mediterranean diet, as compared with a low-fat diet, on seminal parameters of young healthy adults from southern Italy.

METHODS

In a randomized controlled trial, 160 young adults aged 18-30 years were assigned to Mediterranean diet (N.=80) or a low-fat diet (N.=80). The primary outcome measures were changes in semen parameters after six months.

RESULTS

Mean age of participants in the study was 24.7 years. There was no difference in baseline semen parameters of men randomized to Mediterranean diet or low-fat diet. After the entire follow-up, participants in both groups showed a significant increase in sperm concentration and sperm total count, with significant differences favoring the Mediterranean diet group (sperm concentration, 1.93 M/mL 95% CI [1.22 to 3.64], P=0.027; total sperm count 8.02 M 95% CI [1.51 to 15.45], P=0.035). No differences in other semen parameters were found between groups.

CONCLUSIONS

In healthy young adults, the consumption of Mediterranean diet was associated with an improvement of both sperm concentration and total count, as compared with a low-fat diet.

Adherence to diet quality indices in relation to semen quality and reproductive hormones in young men

STUDY QUESTION

Is adherence to an a priori defined diet quality indices [Alternate Healthy Index 2010 (AHEI-2010), relative Mediterranean diet score (rMED) or dietary approaches to stop hypertension (DASH)] associated with semen quality and reproductive hormone levels in young men?

SUMMARY ANSWER

Greater adherence to the DASH diet is related to higher sperm counts.

WHAT IS KNOWN ALREADY

Studies assessing the relationship between dietary intake and male reproductive function have mainly been focused on specific nutrients, food groups or data-driven dietary patterns, but the evidence on a priori defined dietary indices is still scarce.

STUDY DESIGN, SIZE, DURATION

Cross-sectional study of 209 male university students recruited from October 2010 to November 2011 in Murcia Region (Southern Spain).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Healthy young men aged 18-23 years were included in this study. Diet was assessed using a validated food frequency questionnaire and three a priori-defined dietary indices (AHEI-2010, rMED and DASH) were calculated. Linear regression was used to analyze the relation between the three dietary indices and semen quality parameters and reproductive hormone levels accounting for potential confounders and covariates.

MAIN RESULTS AND THE ROLE OF CHANCE

We found statistically significant positive associations between the DASH index and sperm concentration (P, trend = 0.04), total sperm count (P, trend = 0.04) and total motile sperm count (P, trend = 0.02). No associations were observed for other semen parameters or male reproductive hormones.

LIMITATIONS, REASONS FOR CAUTION

Even though we adjusted for several known and suspected confounders we cannot exclude the possibility of residual or unmeasured confounding or chance findings. Subjects were blinded to the study outcomes thus reducing the potential influence on their report of diet. Our sample size may be too small to rule out associations with other semen parameters or reproductive hormones. Causal inference is limited, as usual with all observational studies.

WIDER IMPLICATIONS OF THE FINDINGS

The results suggest that greater adherence to the DASH may help improve sperm counts. This study was carried out on young men from the general population. However, results may differ among other populations (e.g. infertile men). Therefore, further research is needed to confirm these findings and extend these results to other populations.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Fundación Séneca, grants No 08808/PI/08 and No 19443/PI/14; Ministerio de Ciencia e Innovación, Instituto de Salud Carlos III (AES), grants No PI10/00985 and No PI13/01237; and grant P30DK046200 from the National Institutes of Health. Authors have no competing interests to declare.

A narrative review of the effects of sugar-sweetened beverages on human health: A key global health issue

The provision of healthy and safe food is vital for human health, and the addition of unnecessary sugars in foodstuffs is an important global issue, leading to multiple long- and short-term health issues and spiraling costs for individuals and governments alike. The negative effect of excess sugar consumption contributes to adverse health conditions, including obesity, type 2 diabetes, and poor oral health in both high and low resource settings. A key plank of governmental and health promotion bodies' nutritional guidance is to raise public awareness of "hidden" sugars, salt, and fats, such as found in processed foods and sugar-sweetened beverages (SSBs), and guide individuals to reduce their consumption. This rapid narrative review brings together some of the key issues identified in the literature around the consumption of SSBs, including patterns of consumption, the general impact on human health and nutrition, specific effects on oral health and the oral microbiome, and strategies to address over-consumption. The range of long-term adverse effects on health is often misunderstood or unknown by the public. However, some strategies have succeeded in reducing the consumption of SSBs, including public health strategies and interventions and the imposition of taxes or levies, and this article makes recommendations for action.

Saccharum officinarum molasses adversely alters reproductive functions in male wistar rats

The widely reported anti-androgenic effects of refined sugar led to the exploration of safer alternatives. Saccharum officinarum molasses (SOM), a byproduct of sugar processing is gaining popularity as a substitute. This study investigated the effects of SOM and compared them to those of refined sugar on male reproductive functions. Blackstrap® Saccharum officinarum molasses were subjected to phytochemical screening and proximate analysis and fractionated to obtain methanol (SOMMF) and aqueous (SOMAqF) fractions. Twelve groups (n = 5) of adult male Wistar rats received distilled water (Control); 0.8, 2.5, 7.9 g/kg SOM; 0.0064 g/kg sugar (Dangote®); 0.0064 g/kg sugar+7.9 g/kg SOM; 1.0, 3.2, 10.0 g/kg SOMMF and 0.6, 2.0, 6.4 g/kg SOMAqF, respectively. Administrations were done daily by oral gavage for eight weeks. Sperm profile and testicular and epididymal histology were assessed using microscopy. Serum testosterone was quantified using ELISA. Testicular malondialdehyde (MDA) was assayed by spectrophotometry. Data were analyzed using ANOVA at p < 0.05 significance. Sperm count and viability reduced with 7.9 g/kg SOM, Sugar, 3.2 and 10.0 g/kg SOMMF, 2.0 and 6.4 g/kg SOMAqF. Abnormal sperms increased with 7.9 g/kg SOM, Sugar, 2.0 and 6.4 g/kg SOMAqF. Testosterone level reduced with 6.4 g/kg SOMAqF. Testicular MDA increased with SOM, 3.2 and 10.0 g/kg SOMMF and 6.4 g/kg SOMAqF. Seminiferous tubules and epididymal ducts of 7.9 g/kg SOM, Sugar and SOMAqF-treated rats showed anomalies. Saccharum officinarum molasses altered testicular and epididymal integrity via lipid peroxidation, thus reducing sperm quality and androgen levels in male Wistar rats.

Association of Dietary Patterns With Testicular Function in Young Danish Men

IMPORTANCE

Diet may play a role in testicular function, but data on how adherence to different diet patterns influences human testicular function are scarce.

OBJECTIVE

To determine whether adherence to specific dietary patterns is associated with testicular function in young men.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included 2935 young Danish men unselected regarding fertility status who were enrolled from April 1, 2008, through May 31, 2017. Data were analyzed from July 1, 2017, to January 30, 2019.

EXPOSURES

Dietary patterns identified with principal component analysis based on responses to a validated food frequency questionnaire.

MAIN OUTCOMES AND MEASURES

Standard semen quality assessment; serum concentrations of testosterone, free testosterone, estradiol, inhibin B, follicle-stimulating hormone, luteinizing hormone, and sex hormone-binding globulin; and testicular volume measured with ultrasonography.

RESULTS

Among the 2935 participants included in the analysis, median age was 19 (interquartile range, 19-20) years and 2290 (78.0%) had normal body mass index. The 4 dietary patterns identified included Western, prudent, open-sandwich (a traditional Danish eating pattern), and vegetarianlike. The greatest adherence to the prudent pattern was associated with the highest total sperm count (median, 167 [95% CI, 146-183] million), followed by adherence to vegetarianlike (median, 151 [95% CI, 134-168] million) and open-sandwich (median, 146 [95% CI, 131-163] million) patterns. Adherence to the Western pattern was associated with the lowest total sperm count (median, 122 [95% CI, 109-138] million), which was significantly lower than sperm count in the other 3 diet patterns. After adjusting for confounders, the median total sperm count for men in the highest quintile of adherence to the Western pattern was 26 million lower (95% CI, -42 to -9 million) than for men in the lowest quintile of adherence to this pattern. Conversely, the median total sperm count of men in the highest quintile of adherence to the prudent pattern was 43 million (95% CI, 23-63 million) higher than that of men in the lowest quintile. Men with the highest adherence to the Western pattern had a lower median ratio of inhibin B to follicle-stimulating hormone (-12 [95% CI, -20 to -3]) and higher median ratio of free testosterone to luteinizing hormone (10 [95% CI, 2-19]) compared with men with lowest adherence to this pattern.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, adherence to generally healthy diet patterns was associated with better semen quality, with potentially more favorable fertility potential among adult men.

Association of the Dietary Approaches to Stop Hypertension, Physical Activity, and Their Combination with Semen Quality: A Cross-Sectional Study

The influence of individual lifestyle factors is widely described in studies on semen quality. However, their synergistic effect is often neglected. The aim of the study was to examine the association between semen quality and dietary approaches to stop hypertension (DASH) diet, physical activity (PA), and the two separately and in combination. A cross-sectional study was carried out among 207 men aged 20–55. Dietary data were collected by a food frequency questionnaire (FFQ) and analysed according to the DASH scoring index. Physical activity was evaluated by the International Physical Activity Questionnaire. Semen parameters were assessed via the computer-aided semen analysis (CASA). Adherence to the DASH diet was associated with higher sperm count (Δ_T3-T1 = 82.1 mln/ej) and concentration (Δ_T3-T1 = 24.6 mln/mL). Higher PA was related to higher sperm count (Δ_T3-T1 = 69.4 mln/ej), total (Δ_T3-T1 = 11.9%), and progressive motility (Δ_T3-T1 = 8.5%) and morphology (Δ_T3-T1 = 2.8%) in the crude model and remained significant after adjustment. The combination of the DASH diet and PA, was significantly positively associated with sperm count (Δ_T3-T1 = 98.1 mln/ej), sperm concentration (Δ_T3-T1 = 17.5 mln/mL), total (Δ_T3-T1 = 11.8%), and progressive motility (Δ_T3-T1 = 10.0%) and morphology (Δ_T3-T1 = 3.3%) in both models. Adherence to the DASH diet was related to higher sperm count and concentration, whereas after its combination with physical activity it was also positively correlated with sperm motility and morphology.

The Effect of Macronutrients on Reproductive Hormones in Overweight and Obese Men: A Pilot Study

Hypogonadal obese men find it difficult to lose weight. We investigated whether the modification of macronutrient intake can alter testosterone levels independently of the body mass index. Fasted overweight or obese fertile men were asked to consume meals of polyunsaturated fats (PUFA), monounsaturated fats (MUFA), refined carbohydrates (CHO, orange juice, OJ), whey and egg albumin and mixed meals of PUFA and CHO, PUFA and egg albumin, and CHO and egg albumin. Blood was collected at fasting, then hourly for 5 h and analysed to determine the levels of testosterone and other hormones. We found PUFA and MUFA or a mixed meal of PUFA and CHO significantly reduced serum testosterone production to a similar degree over a 5 h period. PUFA decreased serum testosterone levels by 3.2 nmol/L after 1 h compared to baseline (p = 0.023), with this suppression remaining significant up to 5 h postprandially (2.1 nmol/L; p = 0.012). The net overall testosterone levels were reduced by approximately 10 nmol/L × h by PUFA, MUFA and PUFA combined with CHO. CHO alone had little effect on testosterone levels, whereas egg albumin was able to increase them (7.4 cf 2.0 nmol/L × h). Therefore, for men wishing to optimize their testosterone levels, it may be wise to avoid a high fat intake, drink liquids such as water or OJ or even consider fasting. ANZCTR, Australia; ACTRN12617001034325.

The role of environmental factors and lifestyle on male reproductive health, the epigenome, and resulting offspring

Many environmental and genetic variables affect male reproductive health. Some of these factors, however, interfere not only with fertility, but also the non-genomic materials within spermatozoa that can cause phenotypic changes in the offspring, and in some cases, multiple generations. This intergenerational and transgenerational inheritance is due to epigenetic modifications, which is a complex adjunct to traditional Mendelian genetics whose influence on a wide range of human diseases is an active area of research. As the epigenome is a gestalt of individual exposures to the world, ongoing research is evaluating the scope of environmental impacts on the epigenome, as well as its mechanisms for adjusting the phenotypic expression of the organism without changing the code itself. Of particular interest is how these traits are passable to subsequent generations. This article will cover the latest data concerning how the overall quality of nutrition and lifestyle of an individual has been demonstrated to have a significant effect on male reproductive health, and how the accumulation of these modifications are risk factors for the health of their offspring.

Adherence to the Mediterranean diet is positively associated with sperm motility: A cross-sectional analysis

The aim of this cross-sectional analysis is to investigate the associations between the adherence to the Mediterranean Diet (MD) and semen quality parameters. To assess the adherence to the MD, the Trichopoulou score was used. Semen parameters were assessed as described in the 2010 WHO's report and the results are showed across tertiles of MD adherence. A total of 106 participants were included. Compared to those in the lowest MD adherence tertile, participants in the top tertile had statistically significant higher BMI and waist circumference and consumed more energy, and also had statistically significant higher semen pH, and total sperm motility and progressive sperm motility percentages, and lower sperm immotility percentages. Moreover, percentage of total and progressive motility were significantly higher among those subjects in the higher adherence to MD in comparison with those in low-medium adherence category. The multivariable linear regression models evaluating the relationship between the sperm quality parameters and tertiles of MD adherence adjusted by age, energy and BMI showed that compared with the lowest tertile, men in the highest tertile had a higher percentage of total sperm motility [β non-standardized coefficient = 12.785]. These findings suggest that adherence to the MD was positively associated with sperm motility.

Intake of Sugar-sweetened Beverages and Fecundability in a North American Preconception Cohort

BACKGROUND

Dietary factors, including sugar-sweetened beverages, may have adverse effects on fertility. Sugar-sweetened beverages were associated with poor semen quality in cross-sectional studies, and female soda intake has been associated with lower fecundability in some studies.

METHODS

We evaluated the association of female and male sugar-sweetened beverage intake with fecundability among 3,828 women planning pregnancy and 1,045 of their male partners in a North American prospective cohort study. We followed participants until pregnancy or for up to 12 menstrual cycles. Eligible women were aged 21-45 (male partners ≥21), attempting conception for ≤6 cycles, and not using fertility treatments. Participants completed a comprehensive baseline questionnaire, including questions on sugar-sweetened beverage consumption during the previous 4 weeks. We estimated time-to-pregnancy from follow-up questionnaires completed every 2 months by the female partner. We calculated adjusted fecundability ratios (FR) and 95% confidence intervals (CIs) according to intake of sugar- sweetened beverages using proportional probabilities regression.

RESULTS

Both female and male intakes of sugar-sweetened beverages were associated with reduced fecundability (FR = 0.81; 95% CI = 0.70, 0.94 and 0.78; 95% CI = 0.63, 0.95 for ≥7 sugar-sweetened beverages per week compared with none, for females and males, respectively). Fecundability was further reduced among those who drank ≥7 servings per week of sugar-sweetened sodas (FR = 0.75, 95% CI = 0.59, 0.95 for females and 0.67, 95% CI = 0.51, 0.89 for males).

CONCLUSIONS

Sugar-sweetened beverages, particularly sodas and energy drinks, were associated with lower fecundability, but diet soda and fruit juice had little association.

Sugar-sweetened beverage intake and serum testosterone levels in adult males 20-39 years old in the United States

BACKGROUND

This population-based study was designed to investigate whether consumption of sugar-sweetened beverages (SSB) is associated with lower serum total testosterone concentration in men 20-39 years old.

METHODS

All data for this study were retrieved from the National Health and Nutrition Examination Survey (NHANES) 2011-2012. The primary outcome was serum testosterone concentration, and main independent variable was SSB intake. Other variables included age, race/ethnicity, poverty/income ratio, body mass index (BMI), serum cotinine, heavy drinking, and physical activity.

RESULTS

Among all subjects (N = 545), 486 (90.4%) had normal testosterone levels (defined as ≥231 ng/dL) and 59 (9.6%) had low testosterone levels (defined as < 231 ng/dL). Multivariate logistic regression revealed the odds of low testosterone was significantly greater with increasing SSB consumption (Q4 [≥442 kcal/day] vs. Q1 [≤137 kcal/day]), adjusted odds ratio [aOR] = 2.29, p = 0.041]. After adjusting for possible confounding variables, BMI was an independent risk factor for low testosterone level; subjects with BMI ≥ 25 kg/m² had a higher risk of having a low testosterone level than those with BMI < 25 kg/m² (aOR = 3.68, p = 0.044).

CONCLUSION

SSB consumption is significantly associated with low serum testosterone in men 20-39 years old in the United States.

Dietary habits and semen parameters: a systematic narrative review

Semen quality and male fertility are declining worldwide. As it was observed that physiologic and pathologic processes of spermatogenesis can be influenced by diet, the relation between dietary habits and semen parameters has been the focus of much interest. To review the human observational studies on this issue, we performed a systematic literature search, up to November 2016 (MEDLINE and EMBASE). We included all observational full-text papers reporting the relation between dietary habits and semen parameters. Article selection was carried out in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Twenty-three observational studies were included. Overall, 8477 healthy men and 1204 men presenting at Fertility Clinics were included in the selected studies. Even if some inconsistencies are present, possibly due to the different effect of nutrients in fertile and infertile men, results support the hypothesis that diets including fruit and vegetables, for their contents in vitamins, and fish or low-fat dairy products as the main source of proteins, are associated with better semen quality. Recommendations may be confidently provided because of the many beneficial effects of a healthy diet, although further studies are needed to clarify the currently inconsistent findings and to shed light on the underlying mechanisms.

Male Obesity: Epigenetic Origin and Effects in Sperm and Offspring

PURPOSE OF REVIEW

The prevalence of obesity has increased substantially in the current generations of Western countries, and the burden of obesity-related complications has been growing steadily. In men, obesity is not only a major risk factor for serious chronic diseases, concern is growing that the reproductive capacity, and more particularly, their offspring's health may be affected. Obesity-related impaired spermatogenesis is associated with a decrease in microscopic and molecular sperm characteristics and pregnancy success. We hypothesize that epigenetics is an important mediator explaining interactions between an obesogenic environment and sperm/offspring outcomes.

RECENT FINDINGS

Recent studies have explored inter- and transgenerational epigenetic effects in sperm cells and in offspring. Father-to-child effects have been reported in relation to preconceptional nutritional and life-style related factors.

SUMMARY

Here, we summarize the current understanding about obesity and molecular or epigenetic underlying mechanisms in sperm. We identify the obesogenic environment of the father before conception as a potential origin of health or disease in the offspring and include it as part of a new concept, the Paternal Origins of Health and Disease (POHaD).

Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies

BACKGROUND

Infertility is a global public health issue, affecting 15% of all couples of reproductive age. Male factors, including decreased semen quality, are responsible for ~25% of these cases. The dietary pattern, the components of the diet and nutrients have been studied as possible determinants of sperm function and/or fertility.

OBJECTIVE AND RATIONALE

Previous systematic reviews have been made of the few heterogeneous low-quality randomized clinical trials (RCTs) conducted in small samples of participants and investigating the effect of specific nutrients and nutritional supplements on male infertility. However, as yet there has been no systematic review of observational studies.

SEARCH METHODS

A comprehensive systematic review was made of the published literature, from the earliest available online indexing year to November 2016, in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. We have included cross-sectional, case-control and prospective and retrospective studies in which fertile/infertile men were well defined (men with sperm disorders, sperm DNA damage, varicocele or idiopathic infertility). The primary outcomes were semen quality or fecundability. With the data extracted, we evaluated and scored the quality of the studies selected. We excluded RCTs, animal studies, review articles and low-quality studies.

OUTCOMES

A total of 1944 articles were identified, of which 35 were selected for qualitative analysis. Generally, the results indicated that healthy diets rich in some nutrients such as omega-3 fatty acids, some antioxidants (vitamin E, vitamin C, β-carotene, selenium, zinc, cryptoxanthin and lycopene), other vitamins (vitamin D and folate) and low in saturated fatty acids and trans-fatty acids were inversely associated with low semen quality parameters. Fish, shellfish and seafood, poultry, cereals, vegetables and fruits, low-fat dairy and skimmed milk were positively associated with several sperm quality parameters. However, diets rich in processed meat, soy foods, potatoes, full-fat dairy and total dairy products, cheese, coffee, alcohol, sugar-sweetened beverages and sweets have been detrimentally associated with the quality of semen in some studies. As far as fecundability is concerned, a high intake of alcohol, caffeine and red meat and processed meat by males has a negative influence on the chance of pregnancy or fertilization rates in their partners.

WIDER IMPLICATIONS

Male adherence to a healthy diet could improve semen quality and fecundability rates. Since observational studies may prove associations but not causation, the associations summarized in the present review need to be confirmed with large prospective cohort studies and especially with well-designed RCTs.

Coffee and caffeine intake and male infertility: a systematic review

BACKGROUND

Semen quality, a predictor of male fertility, has been suggested declining worldwide. Among other life style factors, male coffee/caffeine consumption was hypothesized to influence semen parameters, but also sperm DNA integrity. To summarize available evidence, we performed a systematic review of observational studies on the relation between coffee/caffeine intake and parameters of male fertility including sperm ploidy, sperm DNA integrity, semen quality and time to pregnancy.

METHODS

A systematic literature search was performed up to November 2016 (MEDLINE and EMBASE). We included all observational papers that reported the relation between male coffee/caffeine intake and reproductive outcomes: 1. semen parameters, 2. sperm DNA characteristics, 3. fecundability. All pertinent reports were retrieved and the relative reference lists were systematically searched in order to identify any potential additional studies that could be included.

RESULTS

We retrieved 28 papers reporting observational information on coffee/caffeine intake and reproductive outcomes. Overall, they included 19,967 men. 1. Semen parameters did not seem affected by caffeine intake, at least caffeine from coffee, tea and cocoa drinks, in most studies. Conversely, other contributions suggested a negative effect of cola-containing beverages and caffeine-containing soft drinks on semen volume, count and concentration. 2. As regards sperm DNA defects, caffeine intake seemed associated with aneuploidy and DNA breaks, but not with other markers of DNA damage. 3. Finally, male coffee drinking was associated to prolonged time to pregnancy in some, but not all, studies.

CONCLUSIONS

The literature suggests that caffeine intake, possibly through sperm DNA damage, may negatively affect male reproductive function. Evidence from epidemiological studies on semen parameters and fertility is however inconsistent and inconclusive. Well-designed studies with predefined criteria for semen analysis, subject selection, and life style habits definition, are essential to reach a consistent evidence on the effect of caffeine on semen parameters and male fertility.

Meat and Nicotinamide: A Causal Role in Human Evolution, History, and Demographics

Hunting for meat was a critical step in all animal and human evolution. A key brain-trophic element in meat is vitamin B3 / nicotinamide. The supply of meat and nicotinamide steadily increased from the Cambrian origin of animal predators ratcheting ever larger brains. This culminated in the 3-million-year evolution of Homo sapiens and our overall demographic success. We view human evolution, recent history, and agricultural and demographic transitions in the light of meat and nicotinamide intake. A biochemical and immunological switch is highlighted that affects fertility in the 'de novo' tryptophan-to-kynurenine-nicotinamide 'immune tolerance' pathway. Longevity relates to nicotinamide adenine dinucleotide consumer pathways. High meat intake correlates with moderate fertility, high intelligence, good health, and longevity with consequent population stability, whereas low meat/high cereal intake (short of starvation) correlates with high fertility, disease, and population booms and busts. Too high a meat intake and fertility falls below replacement levels. Reducing variances in meat consumption might help stabilise population growth and improve human capital.

Phosphodiesterase Inhibitors (PDE Inhibitors) and Male Reproduction

The nonspecific PDE inhibitors, particularly the methylxanthines: caffeine, pentoxifylline (PTX), and theophylline, are known to stimulate sperm motility in vitro and have been used to treat sperm prior to insemination. The in vivo effects are less dramatic. A beneficial effect of caffeine, which is a constituent of some medications, remains controversial. Very high doses of caffeine do have negative effects on fertility endpoints in men and experimental species. The specific PDE5 inhibitors, particularly sildenafil and tadalafil, are prescribed for erectile dysfunction, as well as pulmonary hypertension, lower urinary tract symptoms, and premature ejaculation. PDE5 is expressed throughout the contractile tissues of the male reproductive tract, generally increasing contractility. Some PDE5 inhibitors tend to increase circulating testosterone levels somewhat. For short-term exposure consistent with use prior to intercourse, there appears to be minimal effects on semen quality. Several large, randomized controlled trials (RCTs) in healthy men have not found adverse effects of long-term use of these drugs on semen quality. RCTs in infertile men have demonstrated a modest increase in semen quality. Animal studies at human equivalent doses (HED) have produced similar results in young males, but a study in aging male rats found progressive decreases in epididymal sperm quality accompanied by consistent degeneration of the seminal tubules suggesting that studies in older men might be warranted. A concerning study in mice found lower fertilization rates in males treated with HED of sildenafil and mated the next day to untreated females than for control males. Fertility studies in humans are needed.

Fatty acid composition of spermatozoa is associated with BMI and with semen quality

High body mass index (BMI) is negatively associated with semen quality. In addition, the composition of fatty acids of spermatozoa has been shown to be important for their function. The aim of the study was to examine the association between BMI and the composition of spermatozoa fatty acids in men spanning a broad BMI range. We also analysed the relation between fatty acid composition of spermatozoa and semen characteristics, and the relationship between serum fatty acids and spermatozoa fatty acids. One hundred forty-four men with unknown fertility status were recruited from the general population, from couples with identified female infertility and from morbid obesity centres. Standard semen analysis (WHO) and sperm DNA integrity (DFI) analysis were performed. Fatty acid compositions were assessed by gas chromatography. When adjusted for possible confounders, BMI was negatively associated with levels of sperm docosahexaenoic acid (DHA) (p < 0.001) and palmitic acid (p < 0.001). The amount of sperm DHA correlated positively with total sperm count (r = 0.482), sperm concentration (r = 0.469), sperm vitality (r = 0.354), progressive sperm motility (r = 0.431) and normal sperm morphology (r = 0.265). A negative association was seen between DHA levels and DNA fragmentation index (r = -0.247). Levels of spermatozoa palmitic acid correlated positively with total sperm count (r = 0.227), while levels of linoleic acid correlated negatively (r = -0.254). When adjusted for possible confounders, only the levels of arachidonic acid showed positive correlation between spermatozoa and serum phospholipids (r = 0.262). Changes in the fatty acid composition of spermatozoa could be one of the mechanisms underlying the negative association between BMI and semen quality. The relationship between fatty acids of spermatozoa and serum phospholipids was minor, which indicates that BMI affects fatty acid composition of spermatozoa through regulation of fatty acid metabolism in the testis. The role of dietary intake of fatty acids on the spermatozoa fatty acid composition remains to be elucidated.

Intake of Fruits and Vegetables with Low-to-Moderate Pesticide Residues Is Positively Associated with Semen-Quality Parameters among Young Healthy Men

BACKGROUND

Numerous studies have shown that occupational or environmental pesticide exposure can affect male fertility. There is less evidence, however, regarding any potentially adverse effects of pesticide residues in foods on markers of male fertility potential.

OBJECTIVES

We examined the relations between fruit and vegetable intake, considering pesticide residue status, and semen quality and serum concentrations of reproductive hormones in healthy young men.

METHODS

The Rochester Young Men's Study is a cross-sectional study that recruited men aged 18-22 y (n = 189) in Rochester, New York. Participants completed a questionnaire, provided a semen sample, had a blood sample drawn, and underwent a physical examination at enrollment. Semen samples were analyzed for total sperm count, sperm concentration, morphology, motility, ejaculate volume, total motile count, and total normal count. Dietary intake during the previous year was assessed by a validated food-frequency questionnaire. Fruit and vegetables were categorized as having high [Pesticide Residue Burden Score (PRBS) ≥4] or low-to-moderate (PRBS <4) pesticide residues on the basis of data from the USDA Pesticide Data Program. Linear regression models were used to analyze the associations of fruit and vegetable intake with semen variables and reproductive hormones while adjusting for potential confounding factors.

RESULTS

The total intake of fruit and vegetables was unrelated to semen quality. However, the intake of fruit and vegetables with low-to-moderate pesticide residues was associated with a higher total sperm count and sperm concentration, whereas the intake of fruit and vegetables with high pesticide residues was unrelated to semen quality. On average, men in the highest quartile of low-to-moderate-pesticide fruit and vegetable intake (≥2.8 servings/d) had a 169% (95% CI: 45%, 400%) higher total sperm count and a 173% (95% CI: 57%, 375%) higher sperm concentration than did men in the lowest quartile (<1.1 servings/d; P-trend = 0.003 and 0.0005, respectively). The intake of fruit and vegetables, regardless of pesticide-residue status, was not associated with reproductive hormone concentrations.

CONCLUSIONS

The consumption of fruit and vegetables with low-to-moderate pesticide residues was positively related to sperm counts in young men unselected by fertility status. This suggests that pesticide residues may modify the beneficial effects of fruit and vegetable intake on semen quality.

Caffeine and caffeinated beverage consumption and fecundability in a preconception cohort

Caffeine is an adenosine receptor antagonist that may influence fertility by affecting ovulation, menstrual characteristics, or sperm quality. We studied the association between female and male preconception caffeine intake and fecundability in a North American prospective cohort study of 2135 pregnancy planners. Frequency of caffeinated beverage intake was self-reported at baseline. Outcome data were updated every 8 weeks until reported pregnancy; censoring occurred at 12 months. Adjusted fecundability ratios (FR) and 95% confidence intervals (CI) were estimated using proportional probabilities regression. Total caffeine intake among males, but not females, was associated with fecundability (FR for ≥300 vs. <100mg/day caffeine among males=0.72, 95% CI=0.54-0.96), although the association was not monotonic. With respect to individual beverages, caffeinated tea intake was associated with slight reductions in fecundability among females, and caffeinated soda and energy drink intake were associated with reduced fecundability among males.

The Association between Dietary Patterns and Semen Quality in a General Asian Population of 7282 Males

OBJECTIVE

To explore the associations between different dietary patterns and semen quality in a general Asian male population.

METHODS

Cross-sectional study. Healthy Taiwanese men aged 18 years or older who participated in a standard medical screening program from 2008-2013 run by a private firm were included in this study. Semen parameters including sperm concentration (SC), total sperm motility (TSM), progressive motility (PRM) and normal sperm morphology (NSM) were recorded. A dietary questionnaire was used to categorize the participants into 5 groups: "Healthy diet", "Western diet", "High-carbohydrate diet", "High sweet snacks & sugar-sweetened drinks" and "High-sodium diet".

RESULTS

A total of 7282 men completed the questionnaire regarding dietary pattern, and examination of anthropometric indexes was performed and laboratory data were obtained. A high intake of a "Western diet" resulted in statistically linear declines of SC and NSM (P < 0.001 and P < 0.001). Similarly, a greater intake of "High sweet snacks & sugar-sweetened drinks" was associated with a lower SC (P = 0.001). Increased intake of a "High-carbohydrate diet" was related to higher prevalences of abnormal TSM and PRM (P = 0.012 and P = 0.025). Similarly, a greater intake of a "High-sodium diet" was correlated with an elevated prevalence of abnormal NSM (P = 0.035).

CONCLUSIONS

This study showed that a greater intake of a "Western diet" is associated with poorer SC and NSM, a "High sweet snacks and sugar-sweetened drinks" intake is correlated with a lower SC, and high-carbohydrate food is related to elevated prevalences of abnormal TSM and PRM.