Vitamin D Supplementation Improves Fasting Insulin Levels and HDL Cholesterol in Infertile Men.

CONTEXT: Vitamin D has been linked with glucose and lipid metabolism. Men with impaired gonadal function have a higher risk of metabolic syndrome and mortality, and vitamin D status may be a reversible modulator. OBJECTIVE: This work aimed to determine the effect of daily vitamin D and calcium supplementation for 150 days on glucose and lipid homeostasis in infertile men. METHODS: A single-center, double-blinded, randomized clinical trial (NCT01304927) was conducted. A total of 307 infertile men were randomly assigned (1:1) to a single dose of 300 000 IU cholecalciferol followed by 1400 IU cholecalciferol + 500 mg of calcium daily (n = 151) or placebo (n = 156) for 150 days. Reported metabolic parameters including fasting plasma glucose, glycated hemoglobin A1c, fasting serum insulin, homeostatic model assessment of insulin resistance (HOMA-IR), fasting plasma cholesterols, and triglycerides were secondary end points. The primary end point semen quality has previously been reported. RESULTS: Men receiving vitamin D supplementation improved their vitamin D status, whereas vitamin D status was aggravated in the placebo group characterized by higher serum parathyroid hormone. At the end of the trial, men receiving vitamin D supplementation had 13% lower fasting serum insulin concentrations compared with the placebo-treated group (65 vs 74 pmol/L, P = .018) and 19% lower HOMA-IR (2.2 vs 2.7, P = .025). Moreover, men in the vitamin D group had higher high-density lipoprotein (HDL) cholesterol levels (1.38 vs 1.32 mmol/L, P = .008) compared with the placebo group. CONCLUSION: High-dose vitamin D supplementation has beneficial effects on glucose homeostasis and HDL cholesterol levels in infertile men.

The impact of zinc and folic acid supplementation on sperm DNA methylation: results from the folic acid and zinc supplementation randomized clinical trial (FAZST).

OBJECTIVE: To determine if 6-month folic acid (5 mg) and zinc (30 mg) supplementation impacts sperm DNA methylation patterns. DESIGN: A multicenter, double-blind, block randomized, placebo-controlled trial titled "The Folic Acid and Zinc Supplementation Trial (FAZST)." SETTING: Infertility care centers. PATIENT(S): Male partners (18 years and older) from heterosexual couples (female partners aged 18-45 years) seeking fertility treatment were recruited. INTERVENTION(S): Men were randomized 1:1 to receive folic acid (5 mg) and elemental zinc (30 mg) (n = 713) or a matching placebo (n = 757) daily for 6 months. MAIN OUTCOME MEASURE(S): Sperm DNA methylation was analyzed using the EPIC methylation array (Illumina) at 6 months. Differential sperm DNA methylation was assessed at multiple levels (regional, single cytosine phosphate guanine, etc.). We additionally assessed the impact of supplementation on epigenetic age. RESULT(S): No significant differences were identified between the treatment and placebo groups although some trends appeared to be present. To determine if these trends were noteworthy, we implemented various permutations and found that the patterns we identified were no more than would be expected by random chance. CONCLUSION(S): The data presented here strongly suggest that this supplementation regimen is not effective at altering sperm DNA methylation. These data comport well with previous findings from the FAZST study that found no impact of supplementation on basic semen analysis parameters or live birth. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Identifier: NCT01857310.

Treatment With Cholecalciferol Leads to Increase Of Selected Semen Parameters in Young Infertile Males: Results of a 6-month Interventional Study.

High incidence of infertility along with low vitamin D levels was detected in otherwise healthy young men. The aim is to observe the effect of vitamin D supplementation on semen parameters as assessed by semen analysis in infertile men. In total, 45 men (mean age 36.6 years) in consecutive order were included, of whom 34 finished the study. Subjects were supplemented by vitamin D (cholecalciferol) 2500 IU/day. Vitamin D levels were assessed by HPLC. Semen analysis was performed strictly following 2010 WHO guidelines. Study periods were baseline and month 6. During follow-up, 20 %, 7.4 %, 22 % and 0.7 % increase in serum vitamin D levels, progressive sperm motility, sperm concentration and sperm morphology, respectively, were observed (all p<0.05). At follow-up end, 9 patients (26 %) reached normal sperm parameters of whom 2 fertilized their partner. There was no correlation between vitamin D and semen parameters observed. This study proves that vitamin D supplementation is possibly a modulator of sperm parameters in vitamin D deficient, otherwise healthy men. Although a direct relationship between vitamin D and sperm parameters was not observed obtaining adequate vitamin D levels could likely play a role in the male factor of infertility.

SLC22A14 is a mitochondrial riboflavin transporter required for sperm oxidative phosphorylation and male fertility.

Ablation of Slc22a14 causes male infertility in mice, but the underlying mechanisms remain unknown. Here, we show that SLC22A14 is a riboflavin transporter localized at the inner mitochondrial membrane of the spermatozoa mid-piece and show by genetic, biochemical, multi-omic, and nutritional evidence that riboflavin transport deficiency suppresses the oxidative phosphorylation and reprograms spermatozoa energy metabolism by disrupting flavoenzyme functions. Specifically, we find that fatty acid ß-oxidation (FAO) is defective with significantly reduced levels of acyl-carnitines and metabolites from the TCA cycle (the citric acid cycle) but accumulated triglycerides and free fatty acids in Slc22a14 knockout spermatozoa. We demonstrate that Slc22a14-mediated FAO is essential for spermatozoa energy generation and motility. Furthermore, sperm from wild-type mice treated with a riboflavin-deficient diet mimics those in Slc22a14 knockout mice, confirming that an altered riboflavin level causes spermatozoa morphological and bioenergetic defects. Beyond substantially advancing our understanding of spermatozoa energy metabolism, our study provides an attractive target for the development of male contraceptives.

Exploring the potential impact of nutritionally actionable genetic polymorphisms on idiopathic male infertility: a review of current evidence.

Infertility affects about 15% of the world's population. In 40%-50% of infertile couples, a male factor underlies the problem, but in about 50% of these cases, the etiology of male infertility remains unexplained. Some clinical data show that lifestyle interventions may contribute to male reproductive health. Cessation of unhealthy habits is suggested for preserving male fertility; there is growing evidence that most preexisting comorbidities, such as obesity and metabolic syndrome, are highly likely to have an impact on male fertility. The analysis of genetic polymorphisms implicated in metabolic activity represents one of the most exciting areas in the study of genetic causes of male infertility. Although these polymorphisms are not directly connected with male infertility, they may have a role in specific conditions associated with it, that is, metabolic disorders and oxidative stress pathway genes that are potentially associated with an increased risk of male infertility due to DNA and cell membrane damage. Some studies have examined the impact of individual genetic differences and gene-diet interactions on male infertility, but their results have not been synthesized. We review the current research to identify genetic variants that could be tested to improve the chances of conceiving spontaneously through personalized diet and/or oral vitamin and mineral supplementation, by examining the science of genetic modifiers of dietary factors that affect nutritional status and male fertility.

Alpha-lipoic acid improves sperm motility in infertile men after varicocelectomy: a triple-blind randomized controlled trial.

RESEARCH QUESTION: Does supplementation with alpha-lipoic acid (ALA) enhance sperm parameters and/or the status of sperm lipid peroxidation and DNA fragmentation in men who have undergone microsurgical repair of a varicocele? DESIGN: Individuals with a varicocele who had undergone varicocelectomy were divided into two groups receiving either 600 mg of ALA or an identical placebo for 80 days. Semen samples obtained from the participants before surgery and after completion of the course of medication were analysed and compared. Participants, clinicians and data analysts were blinded to the randomization sequence. RESULTS: In the ALA group, total motility (P = 0.01) and progressive motility (P = 0.002) of the spermatozoa were significantly higher compared with the placebo group after surgery. Sperm lipid peroxidation and DNA damage (assessed by sperm chromatin structure assay) showed significant decreases in both the ALA and placebo groups (P ≤ 0.02) after treatment. CONCLUSIONS: An 80-day course of ALA medication after surgical repair improves total motility and progressive motility of the spermatozoa in individuals with a varicocele.

Phytoestrogen intake and other dietary risk factors for low motile sperm count and poor sperm morphology.

BACKGROUND: Few potentially modifiable risk factors of male infertility have been identified, and while different diets and food groups have been associated with male infertility, evidence linking dietary factors including phytoestrogens and semen quality is limited and contradictory. OBJECTIVES: To study the associations between phytoestrogen intake and other dietary factors and semen quality. MATERIALS AND METHODS: A case-referent study was undertaken of the male partners, of couples attempting conception with unprotected intercourse for 12 months or more without success, recruited from 14 UK assisted reproduction clinics. A total of 1907 participants completed occupational, lifestyle and dietary questionnaires before semen quality (concentration, motility and morphology) were assessed. Food intake was estimated by a 65-item food frequency questionnaire (FFQ) covering the 12 months prior to recruitment. Analyses of dietary risk factors for low motile sperm concentration (MSC: <4.8 × 106 /mL) and poor sperm morphology (PM: <4% normal morphology) used unconditional logistic regression, accounting for clustering of subjects within the clinics, first without, and then with, adjustment for confounders associated with that outcome. RESULTS: High consumption of daidzein (≥13.74 µg/d), a phytoestrogen found in soy products, was a protective factor for MSC with an odds ratio (95%CI) of 0.58 (0.42-0.82) after adjustment for clustering and potential confounding. Dietary risk factors for PM after similar adjustment showed that drinking whole milk (OR 0.67, 95%CI 0.47-0.96) and eating red meat were protective with an OR 0.67 (0.46-0.99) for eating red meat >3 times/wk. DISCUSSION: In this case-referent study of men attending an infertility clinic for fertility diagnosis, we have identified that low MSC is inversely associated with daidzein intake. In contrast, daidzein intake was not associated with PM but eating red milk and drinking whole milk were protective. CONCLUSIONS: Dietary factors associated with semen quality were identified, suggesting that male fertility might be improved by dietary changes.

Dietary supplementation with a novel l-carnitine multi-micronutrient in idiopathic male subfertility involving oligo-, astheno-, teratozoospermia: A randomized clinical study.

OBJECTIVE: To study the influence of a multi-component nutrient dietary supplement on sperm parameters and pregnancy rates in idiopathic male infertility (IMI) with oligo-, astheno-, and teratozoospermia. DESIGN: A randomized, double-blind, placebo-controlled, prospective, parallel arms (1:1 allocation ratio), multi-center clinical trial. SETTINGS: Eight urology/reproductive health clinical centers located in Ukraine. PATIENTS: Eighty-three males aged 21-50 years with IMI and at least 1 of 3 abnormal values: total sperm concentration < 15 million/ml or/and spermatozoa progressive motility < 32% or/and forms with normal morphology < 4%. INTERVENTION(S): Patients were randomly allocated verum test dietary supplement (TDS) containing l-carnitine/acetyl-l-carnitine, l-arginine, glutathione, co-enzyme Q10, zinc, vitamin B9 , vitamin B12 , selenium, or placebo 1 time daily for 6 months. MAIN OUTCOME(S): The primary outcome measure was the percentage of normal spermiograms (concentration ≥ 15 million/ml and ≥ 32% of spermatozoa with progressive motility and ≥ 4% of normal forms) at month 0, 2, and 4. The percentage of pregnancies served the secondary outcome endpoint. Differences between the groups were assessed in z-test for proportions. RESULTS: All males finished the study. At month 4, 29/42 (69.0%) males in the verum and 9/41 (22.0%) had normal spermiograms (P < .001). The percentage of spontaneous pregnancies in the verum group was greater than in the placebo group (10/42, 23.8% vs. 2/41, 4.9%, respectively, P = .017). There were no reportable supplement-associated adverse events. CONCLUSION: Specific multi-nutrient combination l-carnitine/l-acetyl-carnitine, l-arginine, glutathione, co-enzyme-Q, zinc, folic acid, cyanocobalamin, and selenium can improve sperm quality in males with IMI and increase pregnancy rates.

Body mass index and age correlate with antioxidant supplementation effects on sperm quality: Post hoc analyses from a double-blind placebo-controlled trial.

Spermatozoa are vulnerable to lack of energy and oxidative stress as a result of elevated levels of reactive oxygen species. Therefore, it is essential that appropriate nutrients are available during maturation. This randomised, double-blind, placebo-controlled trial investigated the effect of 6-month supplementation with carnitines and other micronutrients on sperm quality in 104 subjects with oligo- and/or astheno- and/or teratozoospermia with or without varicocele. Semen analyses were done at the beginning and end of the treatment. In addition to main analyses, post hoc analyses for age and body mass index (BMI) were carried out. Results were interpreted by dividing the population into two age and BMI classes. In 94 patients who completed the study, all sperm parameters increased in supplemented patients compared to the placebo group. A significant (p = .0272) difference in supplementation efficacy was observed for total motility on patients with varicocele and BMI < 25. In the same group, also the progressive motility was significantly superior (p = .0159). For Responder analysis, total motility results were confirmed in both the cited group (p = .0066) and in the varicocele group with BMI < 25 and age < 35 (p = .0078). This study suggests that supplementation is more effective in subjects with varicocele younger than 35 years with BMI < 25.

The effects of lycopene supplement on the spermatogram and seminal oxidative stress in infertile men: A randomized, double-blind, placebo-controlled clinical trial.

Infertility is a major, worldwide problem that is affected, and mediated, by several factors, in particular, oxidative stress. Thus, the aim of this study was to evaluate the effect of lycopene supplementation on spermatogram and seminal oxidative stress. In this randomized, double-blind, placebo-controlled trial study, 44 infertile men with oligozoospermia were randomly divided into two groups: The experimental group was supplemented with 25 mg of lycopene, and the control group received placebo for 12 weeks. Anthropometric, physical activity and dietary assessment, semen analysis, total antioxidant capacity (TAC), malondialdehyde, and glutathione peroxidase were measured pre- and post-intervention. At the end of the study, there was a significant increase in total sperm count and concentration in the lycopene group, and the latter total count remained significant after adjustment (p < .05). Intragroup analysis showed a significant increase in ejaculate volume, total sperm count, concentration total motility, nonprogressive, and nonmotility in lycopene group (p < .05). The TAC changes, in both groups, remained significant after adjustment (p < .05). Also, within-group analysis showed a significant increase in TAC levels (p < .05). Lycopene supplement can improve sperm parameters and oxidative stress biomarkers in oligozoospermia infertile men; however, further studies with larger sample size and duration are required.

The influence of omega-3 fatty acids on semen quality markers: a systematic PRISMA review.

BACKGROUND: Infertility affects about 15% of all couples worldwide. Male factors such as decreased semen quality contribute to around 40% of the cases. Recent reviews have shown that different foods and nutrients may improve semen quality. OBJECTIVES: We conducted a systematic review in order to investigate whether intake of omega-3 fatty acids can improve semen quality markers. MATERIALS AND METHODS: A systematic search of PubMed, Embase, and Cochrane was conducted in adherence with the PRISMA guideline from the earliest available online indexing year to October 2018. Keywords related to male fertility or infertility was combined with words describing omega-3 fatty acids and dietary fish intake. RCTs and observational studies on infertile and fertile men were included. Studies were considered eligible if they met the inclusion criteria, evaluated either the effect of omega-3 fatty acids or dietary fish intake and had semen quality as primary outcome. RESULTS: Thousand and seventy four records were screened, and sixteen studies were ultimately included. Fourteen of the included studies found an improvement or association between omega-3 and at least one semen quality marker. As the studies were very inhomogeneous in participants (fertile/infertile, age, BMI, ethnicity etc), no meta-analysis was performed. DISCUSSION: The findings in this review are limited by the few available RCTs. Furthermore, RCTs were very heterogenetic according to study population, sample size, dosage of omega-3, and durations of follow up. Results from the observational studies might have been affected by recall bias and confounded by lifestyle factors. CONCLUSION: Based on the findings in this review, omega-3 supplements and dietary intake of omega-3 might improve semen quality parameters in infertile men and men from couples seeking fertility treatment. However, more research is required in order to fully clarify the effect of omega-3 on semen quality and research with fecundity as end point is needed.

Effect of Dietary n-3 Source on Rabbit Male Reproduction.

In the last two decades, the human sperm count linearly decreased in Western countries. Health problems, lifestyle, pollutants, and dietary behaviours are considered as the main risk factors, and the unbalance of dietary n-6/n-3 fatty acids is one of the most relevant. The aim of the present research is to study the effect of different dietary sources of n-3 polyunsaturated fatty acids (PUFA) on reproductive traits using rabbit buck as the animal model. Fifteen rabbit bucks were assigned to three experimental groups: the control group, the FLAX group fed 10% extruded flaxseed, and the FISH group fed 3.5% fish oil for 110 days (50-day adaptation and 60-day experimental periods). Semen samples were collected weekly, whereas blood was collected every two weeks for the analytical determination of semen traits, oxidative status, fatty acid profiles, isoprostanes, neuroprostanes, and the immunocytochemistry of docosahexaenoic acid (DHA) and eicosapentaenoic (EPA) acid. At the end of the trial, the rabbits were killed and the testes were removed and stored for the analysis of fatty acid profile and immunocytochemistry. Results showed that dietary administration of n-3 PUFA improved the track speed of the sperm and increased the n-3 long-chain PUFA mainly confined in the sperm tail. Seminal plasma increased the thiobarbituric reactive substances (TBARs) by three times in the groups fed supplemental n-3, whereas the F2-isoprotanes (F2-IsoPs) and F4-neuroprostanes (F4-NeuroPs) were lower and higher, respectively, in both supplemented groups than in the control. The testes and sperm showed a higher DHA and EPA distribution in rabbits from the n-3 supplemented groups compared with the control. In conclusion, supplemental dietary n-3 PUFA improved sperm motion traits and resulted in an enrichment of membrane fatty acid in the sperm and testes of the rabbits. However, such an increased amount of PUFA negatively affected the sperm oxidative status, which was mainly correlated with the generation of F4-NeuroPs with respect to F2-IsoPs. Accordingly, the latter cannot be considered a good marker of oxidation when diets rich in n-3 PUFA are provided.

Hypospermia Improvement in Dogs Fed on a Nutraceutical Diet.

Male dog infertility may represent a serious concern in the canine breeding market. The aim of this clinical evaluation was to test the efficacy of a commercially available nutraceutical diet, enriched with Lepidium meyenii, Tribulus terrestris, L-carnitine, zinc, omega-3 (N-3) fatty acids, beta-carotene, vitamin E, and folic acid, in 28 male dogs suffering from infertility associated with hypospermia. All dogs received the diet over a period of 100 days. At the end of the evaluation period, no adverse effects, including head and tail anomalies percentage onset, were reported. Interestingly, motility percentage, semen volume and concentration, and total number of sperms per ejaculation significantly increased. Further investigations on a wider cohort of dogs might be useful to better correlate the presence of oxytetracycline in pet's diet and the onset of infertility and clearly assess the action mechanism of an oxytetracycline-free nutraceutical diet.

Effect of Coenzyme Q10 Supplementation on Testosterone.

Enhancing testosterone production in males is a continuous research direction for many scientists in the field, due to its role as a principal sex hormone and as a crucial modulator of well-being and general health in humans. Since 1978, there have been more than 30 studies that have connected coenzyme Q10 and testosterone. Such a link is attributable to the vigorous biological role of coenzyme Q10 as a crucial member in the energy production route in humans and animals, which is thought to have a positive influence on testosterone production, and hence on infertility, particularly male infertility. However, this connection has not yet been deliberated. The present work systematically reviews and summarizes the influence of coenzyme Q10 supplementation on testosterone. To accomplish this purpose, the Scopus, PubMed, and Web of Science databases were searched using the keywords "coenzyme Q10" versus "testosterone" for English language papers from November 1978 through October 2018. Relevant articles were also discussed and included to address an integral discussion. In summary, to date the studies conducted on human males reveal insignificant effects of coenzyme Q10 supplementation on testosterone. Similarly, rather than the reproductive toxicity studies, the studies conducted on animals did not show any positive influence of coenzyme Q10 on testosterone. However, coenzyme Q10 supplementation was found to ameliorate the reduction in testosterone induced by chemical reproductive toxicants, mainly by neutralizing the damaging effect of the generated free radicals. However, collectively these findings require further confirmation by additional research studies.

Diet and men's fertility: does diet affect sperm quality?

Male contribution to a couple's fecundity is important, and identifying the dietary factors that can influence male fertility potential is of high importance. Despite this importance, there are currently no clear clinical guidelines for male patients seeking fertility treatment. In this review, we present the most up-to-date evidence about diet and male fertility in humans. We focus on the dietary factors necessary for production of healthy functioning sperm with high fertility potential. Based on this review, men may be encouraged to use antioxidant supplements and to follow dietary patterns favoring the consumption of seafood, poultry, nuts, whole grains, fruits, and vegetables. Evidence is strongest for recommending the use of antioxidant supplements to men in couples undergoing infertility treatment-although the specific antioxidants and doses remain unclear-and increasing consumption of omega-3 fatty acids from fish and nuts.

Dietary patterns are positively associated with semen quality.

OBJECTIVE: To study association of semen quality with a priori whole dietary pattern indexes, which reflect real-world dietary practices and the numerous combinations by which foods are consumed: Healthy Eating Index (HEI), Dietary Approaches to Stop Hypertension (DASH), alternate Mediterranean Diet score (aMED), and Alternative Healthy Eating Index (AHEI). DESIGN: A cross-sectional single-center study. SETTING: Hospital fertility center and university. PATIENT(S): A total of 280 men attending fertility center from 2012 to 2015. INTERVENTION(S): Food frequency questionnaire (FFQ) and semen and sperm analysis. MAIN OUTCOME MEASURE(S): Food consumption with the use of FFQ and HEI, AHEI, aMED, DASH nutritional individual scoring indexes. Semen parameters, including semen volume, sperm concentration, motility, total count, and morphology. RESULT(S): Comparing the highest and lowest quartiles of the nutritional indexes, men in the highest quartiles of HEI, AHEI, aMed, and DASH indexes had significantly higher adjusted means of sperm concentration (by 10%, 45%, and 24% for HEI, AHEI, and DASH, respectively), normal sperm morphology (by 21% and 8% for AHEI and DASH, respectively), total sperm count (by 29% for AHEI), and sperm motility (by 6% and 11% for aMed and HEI, respectively). CONCLUSION(S): Adherence to any of the four dietary indexes is associated with better overall sperm quality, with AHEI best associated. Following our novel findings, we recommend using AHEI as a clinical and practical tool for public whole nutritional recommendation for semen quality.

Prednisone treatment in infertile patients with oligozoospermia and accessory gland inflammatory alterations.

The association between inflammation of the male reproductive system and oligozoospermia has been frequently reported in the clinical work-up of male infertility. To improve sperm parameters in infertile patients with genital inflammation, many phytochemical and nutraceutical drugs are currently being used. However, their use is still empirical and no conclusive data have been provided about their efficacy. The treatment with steroid anti-inflammatory drugs might be useful in reducing inflammation and improving sperm parameters, thus increasing the fertility outcome. The aim of this study was to evaluate if glucocorticoid treatment improves seminal parameters in infertile oligozoospermic patients presenting signs of accessory gland inflammation at genital ultrasound. A total of 90 infertile patients were enrolled in the study. They presented normal testicular volume, normal FSH plasma levels, the presence of various degrees of oligozoospermia, associated with scrotal and trans-rectal ultrasound signs indicative of accessory gland inflammation, but negative microbiological analysis on semen and/or prostatic secretions. Patients were randomly allocated into three groups of treatment, receiving, respectively, 5, 12.5, and 25 mg daily oral Prednisone for one month. Seminal parameters were evaluated at admission and after treatment. In patients undergoing Prednisone treatment at a daily dose of 5 mg we observed a significant increase in total sperm count. At a daily dose of 12.5 mg, Prednisone treatment improved sperm concentration, total sperm count, and the percentage of sperm motility. Twenty-five mg of Prednisone led to significant improvement in all the sperm parameters, except for semen volume. These results clearly demonstrate that Prednisone treatment can significantly improve sperm parameters in a selected population of oligozoospermic patients. These findings suggest that Prednisone treatment should be considered in idiopathic oligozoospermic patients with supposed normal spermatogenesis and accessory gland inflammatory alterations, in order to improve sperm parameters and fertility outcome.

Coenzyme Q10 Intake From Food and Semen Parameters in a Subfertile Population.

OBJECTIVE: To assess the association between coenzyme Q10 (CoQ10) intake from food sources and semen quality. We assessed this association in a prospective cohort of men attending a fertility clinic. CoQ10 supplementation has been associated with improvements in semen parameters. However, the impact of CoQ10 intake from food sources on semen quality has not been investigated. MATERIALS AND METHODS: Subfertile couples seeking fertility evaluation at the Massachusetts General Hospital Fertility Center were invited to participate in an ongoing study of environmental factors and fertility. In total, 211 male participants completed a validated food frequency questionnaire and provided 476 semen samples. Multivariable linear mixed models were used to examine the relation between CoQ10 intake from food and semen parameters while adjusting for potential confounders and accounting for within-person correlations. RESULTS: Mean dietary CoQ10 intake was 19.2 mg/day (2.4-247.2 mg/day). No subjects were taking CoQ10 supplements. There were no associations between dietary CoQ10 intake from food and conventional semen parameters. The adjusted mean difference (95% confidence interval) comparing men in the top and bottom quartiles of CoQ10 intake from food were -3.1 mil/mL (95% confidence interval -29.5, 38.8 mil/mL) for sperm concentration, -4.5% (-15.1%, 6.0%) for total motility, -1.3% for progressive motility (-8.4%, 5.7%), and 0.3% (-1.4%, 2.0%) for sperm morphology. CONCLUSION: CoQ10 intake from food was not related to semen parameters among subfertile men. Mean dietary intake of CoQ10 in this study was 10-fold lower than the supplemental dose used in clinical trials showing improved sperm motility. CoQ10 intake from food alone may be insufficient to optimize semen parameters.