Dietary fat and semen quality among men attending a fertility clinic

Paternal diet-induced obesity retards early mouse embryo development, mitochondrial activity and pregnancy health

Worldwide, 48% of adult males are overweight or obese. An association between infertility and excessive body weight is now accepted, although focus remains primarily on females. It has been shown that parental obesity results in compromised embryo development, disproportionate changes in embryo metabolism and reduced blastocyst cell number. The aim of this study was to determine whether paternal obesity has negative effects on the resultant embryo. Specifically, using in vitro fertilisation (IVF), we wanted to isolate the functional effects of obesity on sperm by examining the subsequent embryo both pre- and post-implantation. Epididymal sperm was collected from age matched normal and obese C57BL/6 mice and cryopreserved for subsequent IVF with oocytes collected from Swiss females (normal diet/weight). Obesity was induced in male mice by feeding a high fat diet of 22% fat for 10 weeks. Resultant embryos were cultured individually and development monitored using time-lapse microscopy. Paternal obesity resulted in a significant delay in preimplantation embryo development as early as syngamy (P<0.05). Metabolic parameters were measured across key developmental stages, demonstrating significant reduction in mitochondrial membrane potential (P<0.01). Blastocysts were stained to determine trophectoderm (TE) and inner cell mass (ICM) cell numbers, revealing significant differences in the ratio of cell allocation to TE and ICM lineages (P<0.01). Functional studies examining blastocyst attachment, growth and implantation demonstrated that blastocysts derived from sperm of obese males displayed significantly reduced outgrowth on fibronectin in vitro (P<0.05) and retarded fetal development in vivo following embryo transfer (P<0.05). Taken together, these data clearly demonstrate that paternal obesity has significant negative effects on the embryo at a variety of key early developmental stages, resulting in delayed development, reduced placental size and smaller offspring.

Environmental mercury exposure, semen quality and reproductive hormones in Greenlandic Inuit and European men: a cross-sectional study

Several animal studies indicate that mercury is a male reproductive toxicant, but human studies are few and contradictory. We examined semen characteristics and serum levels of reproductive hormones in relation to environmental exposure to mercury. Blood and semen samples were collected from 529 male partners of pregnant women living in Greenland, Poland and Ukraine between May 2002 and February 2004. The median concentration of the total content of mercury in whole blood was 9.2 ng ml(-1) in Greenland (0.2-385.8 ng ml(-1)), 1.0 ng ml(-1) in Poland (0.2-6.4 ng ml(-1)) and 1.0 ng ml(-1) in Ukraine (0.2-4.9 ng ml(-1)). We found a significantly positive association between the blood levels of mercury and serum concentration of inhibin B in men from Greenland (β=0.074, 95% confidence interval (CI)=0.021 to 0.126) and in an analysis including men from all three regions (β=0.067, 95% CI=0.024 to 0.110). The association may be due to beneficial effects of polyunsaturated fatty acids (PUFAs), which are contained in seafood and fish. No significant association (P>0.05) was found between blood concentrations of mercury and any of the other measured semen characteristics (semen volume, total sperm count, sperm concentration, morphology and motility) and reproductive hormones (free androgen index (FAI), follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone and LH × testosterone) in any region. In conclusion, the findings do not provide evidence that environmental mercury exposure in Greenlandic and European men with median whole blood concentration up to 10 ng ml(-1) has adverse effects on biomarkers of male reproductive health.

Spermatozoa and seminal plasma fatty acids as predictors of cryopreservation success

There is a lack of information about the importance of fatty acid composition of the human sperm membranes and seminal plasma in the cryopreservation procedure. Our aims were to study the possible relationships between the fatty acid composition of human spermatozoa or seminal fluid before freezing, and the sperm quality, measured in terms of viability and motility, before and after freezing-thawing. A further objective of this study was to determine whether the antioxidant capacity (TAC) of the seminal plasma is related to fatty acid (FA) composition and to success of the cryopreservation process. Polyunsaturated fatty acids (PUFA), ω3 PUFAs and docosahexaenoic acid (DHA) in spermatozoa were significantly positively correlated with sperm viability and motility parameters before and after freezing. An inverse relationship was found for monounsaturated (MUFA), ratio ω6/ω3, ratio saturated saturated fatty acids/PUFA (SFA/PUFA) with the seminal parameters. Seminal plasma fatty acid composition was not related to viability. However, motility parameters before and after freezing were related to stearic acid (C18:0) and DHA. TAC in seminal plasma was directly related to PUFA, w3 and DHA. On the other hand, SFA, C22:0, C24:0 and MUFA in seminal plasma were inversely related to the antioxidant capacity. TAC was directly correlated with motion parameters after thawing, We described a significant correlation between the fatty acid composition of the human spermatozoa or seminal plasma and the sperm parameters of the samples after thawing. PUFA, W3 and specially DHA are directly correlated with sperm motility and viability after freezing/thawing, and MUFA was inversely correlated. This means that in the future the fatty acid composition could be used as a predictor of the capacity of cryopreservation. On the other hand, we could design further procedures to modify the lipid composition or/and antioxidant capacity of ejaculate to make it more resistant to the cryopreservation process.

Aging gonads, glands, and gametes: immutable or partially reversible changes?

Decreased ovarian testosterone production, granulosa cell dysfunction, oocyte telomere shortening and mitochondrial defects, and sperm DNA fragmentation all contribute to reproductive aging. Maneuvers aimed at correcting these abnormalities, including reduction of oxidative stress, improved lifestyle and nutrition, and the role of supplements, are reviewed.

Walnuts improve semen quality in men consuming a Western-style diet: randomized control dietary intervention trial

We tested the hypothesis that 75 g of whole-shelled walnuts/day added to the Western-style diet of healthy young men would beneficially affect semen quality. A randomized, parallel two-group dietary intervention trial with single-blind masking of outcome assessors was conducted with 117 healthy men, age 21-35 yr old, who routinely consumed a Western-style diet. The primary outcome was improvement in conventional semen parameters and sperm aneuploidy from baseline to 12 wk. Secondary endpoints included blood serum and sperm fatty acid (FA) profiles, sex hormones, and serum folate. The group consuming walnuts (n = 59) experienced improvement in sperm vitality, motility, and morphology, but no change was seen in the group continuing their usual diet but avoiding tree nuts (n = 58). Comparing differences between the groups from baseline, significance was found for vitality (P = 0.003), motility (P = 0.009), and morphology (normal forms; P = 0.04). Serum FA profiles improved in the walnut group with increases in omega-6 (P = 0.0004) and omega-3 (P = 0.0007) but not in the control group. The plant source of omega-3, alpha-linolenic acid (ALA) increased (P = 0.0001). Sperm aneuploidy was inversely correlated with sperm ALA, particularly sex chromosome nullisomy (Spearman correlation, -0.41, P = 0.002). Findings demonstrated that walnuts added to a Western-style diet improved sperm vitality, motility, and morphology.

Dietary patterns and semen quality in young men

STUDY QUESTION

Are different dietary patterns associated with semen parameters in young men?

STUDY ANSWER

The consumption of a Prudent dietary pattern was significantly associated with higher progressive sperm motility and unrelated to sperm concentration and morphology. The consumption of a Western dietary pattern was unrelated to conventional semen quality parameters.

WHAT IS KNOWN ALREADY

Over the past decades there has been evidence of a concomitant decline in sperm and diet quality. Yet whether diet composition influences semen quality remains largely unexplored.

STUDY DESIGN, SIZE, DURATION

The Rochester Young Men's Study (n= 188) was a cross-sectional study conducted between 2009 and 2010 at the University of Rochester.

PARTICIPANTS, SETTING, METHODS

Men aged 18-22 years were included in this analysis. Diet was assessed via food frequency questionnaire and dietary patterns were identified by factor analysis. Linear regression was used to analyze the relation between diet patterns and conventional semen quality parameters (sperm concentration, progressive motility and morphology) adjusting for abstinence time, multivitamin use, race, smoking status, BMI, recruitment period, moderate-to-intense exercise and total calorie intake.

RESULTS

Two dietary patterns were identified by factor analysis. The 'Western' pattern was characterized by high intake of red and processed meat, refined grains, pizza, snacks, high-energy drinks and sweets. The 'Prudent' pattern was characterized by high intake of fish, chicken, fruit, vegetables, legumes and whole grains. The Prudent pattern was positively associated with percent progressively motile sperm in multivariate models (P-trend = 0.04). Men in the highest quartile of the Prudent diet had 11.3% (95% CI 1.3, 21.3) higher % progressively motile sperm compared with men in the lowest quartile. The Prudent pattern was unrelated to sperm concentration and morphology. The Western pattern was not associated with any semen parameter.

LIMITATIONS

This was a cross-sectional and observational study, which limited our ability to determine causality of diet on semen quality parameters.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings support the suggestion that a diet rich in fruits, vegetables, chicken, fish and whole grains may be an inexpensive and safe way to improve at least one measure of semen quality.

STUDY FUNDING/COMPETING INTERESTS

The authors are supported by NIH grant T32DK007703-16 and P30DK46200 and European Union DEER Grant 212844. The authors have no competing interests to declare.

Effect of n-3 fatty acids and α-tocopherol on post-thaw parameters and fatty acid composition of bovine sperm

PURPOSE

This study was designed to determine the combined effects of adding source of n-3 fatty acids (FA) and α-tocopherol (vitamin E, VE) to semen extender on freezability and FA composition of Brown Swiss bull sperm.

METHODS

Semen samples were collected from 6 Brown Swiss bulls and pooled. In the first trial, semen was divided into 12 groups including 4 levels of n-3 FA (0, 1, 10, 100 ng ml(-1)) and 3 levels of VE (0. 0.2, 0.4 mM). Motility, viability and fatty acid composition of sperm were measured.

RESULTS

The treatment of 10 ng ml(-1) n-3 FA and 0.4 mM VE had the best post-thaw sperm characteristics (P < 0.01). In the second trial, sperm lipid composition of this treatment and control (without FA and VE) was determined. Supplementing n-3 fatty acids during cryopreservation increased docosahexaenoic acid (DHA) and the ratio of n-3 to n-6 FA in sperm before freezing and after thawing.

CONCLUSIONS

The results suggest that combining the optimal level of n-3 FA (10 ng ml(-1)) with the highest level of VE tested (0.4 mM) in a semen extender changed the membrane lipid composition and improved freezablity of Brown Swiss bull sperm.