Mediterranean Diet Score was positively associated with normal sperm concentration and total count, but not with semen volume.

Three hundred nine men, age range 27–60, were enrolled: 19.3% had semen volume < 1.5 mL, 30.5% sperm concentration <15 mil/mL, and 32.1% total count <39 mil. MDS was low (0–3) in 86 men (27.8%), intermediate (4–5) in 131 (42.4%), and high (6–9) in 92 (29.8%). Semen volume was not associated with MDS. Compared to the highest MDS category (6–9), the ORs for low sperm concentration were 1.34 (95% CI 0.69–2.50) for MDS 4–5 and 2.42 (95% CI 1.21–4.83) for MDS 0–3, with significant trend ( p = 0.011). The corresponding estimates for total count were 1.26 (95% CI 0.66–2.42) and 2.08 (95% CI 1.05–4.12), with significant trend ( p = 0.034). These findings were consistent in strata of history of reproductive organ diseases.

Patients were enrolled in an Italian Fertility Clinic. Couples undergoing assisted reproduction techniques (ART) were interviewed to obtain information on personal and health history, lifestyle habits, and diet, on the day of oocyte retrieval. On the same day, a semen sample was also collected and analyzed to proceed with ART. Adherence to Mediterranean diet was evaluated using a Mediterranean Diet Score (MDS). Odds ratios (OR) and 95% confidence intervals (CI) were calculated for semen volume <1.5 mL, sperm concentration <15 mil/mL, and total count <39 mil.

Several diet patterns have been suggested as involved in processes of spermatogenesis and thus in male subfertility. To study the relation between Mediterranean diet and abnormal sperm parameters in men of subfertile couples, we performed a cross‐sectional analysis of baseline data from a prospective cohort study.

Introduction Fertility problems affect approximately 15% of couples, and up to 30% of cases seem to be accounted for by male factors (Nyboe Andersen et al., 2008; Thoma et al., 2013). Recently, a comprehensive meta‐analysis has shown that, over the past 50 years, sperm concentration has declined by an overall 32% in European men (Sengupta et al., 2017). Sub optimal semen quality is, in most cases, of idiopathic origin, with no clear explanation for impaired spermatogenesis. The causal link between environmental factors and impaired male fertility is still weak, even if there is growing evidence suggesting that selected environmental conditions and lifestyle habits may influence semen quality (Gabrielsen & Tanrikut, 2016). Besides the well‐known genetic and endocrine factors (Visser & Repping, 2010; Ohlander et al., 2016), smoking, overweight, physical activity, alcohol intake and dietary factors (Ricci et al., 2018) have been suggested to play an important role. In particular, dietary patterns, including fruit, vegetables, fish, and low intake of red meat and saturated fats, have been associated with better semen quality, although they did not consistently relate to all semen variables (Cutillas‐Tolín et al., 2015; Karayiannis et al., 2017; Oostingh et al., 2017). To provide further information on this topic in the Italian population, we performed a cross‐sectional analysis of data from a study on the relationship between lifestyle and diet patterns and sperm parameters, in men of subfertile couples presenting to an Italian Fertility Clinic and candidate to assisted reproductive procedures.

Subjects and Methods From September 2014 to December 2016, on randomly selected days, subfertile couples, presenting for evaluation to the Fertility Unit of Fondazione IRCCS Ca’ Granda Ospedale Maggiore, Policlinico, Milan, and eligible for assisted reproduction technologies (ART), were invited to participate in an ongoing prospective cohort study on the role of lifestyle habits and diet on ART outcome. The study protocol was approved by the Institutional Review Board of Fondazione IRCCS Ca’ Granda, Ospedale Maggiore, Policlinico (Milan). All procedures were in accord with the Helsinki Declaration, and all participants provided written informed consent. Study participation was proposed during the diagnostic phase. Couples were interviewed on the day of oocyte retrieval. On the same day, a semen sample was also collected and analyzed to proceed with in vitro fertilization (IVF) or intra‐cytoplasmic sperm injection (ICSI). The time interval between the proposal of the study and the interview was generally less than one month. Both partners of couples who agreed to participate were interviewed by centrally trained personnel using a standard questionnaire to obtain information on general socio‐demographic characteristics, personal, and health history and lifestyle habits (including smoking, physical activity, alcohol intake, and methylxanthine‐containing beverages consumption). The present study reported exclusively on evidence obtained from the male partner. Couples that could not speak Italian were excluded from the study. The overall participation rate was close to 95%. This high participation rate was mainly due to the fact that couples were interviewed during the period spent waiting for the different diagnostic stages before actual ART procedure. Considering this down time and the not sensitive character of questions, couples did not usually refuse to answer the questionnaire. Information on diet was obtained using a previously validated food frequency questionnaire (FFQ) (Franceschi et al., 1993, 1995; Decarli et al., 1996). Patients were asked to report their usual weekly food consumption in the last year. The FFQ includes the average weekly consumption of 78 food items or food groups (including the major sources of animal fats—i.e., red meat, milk, cheese, ham, salami—folates, vitamins—vegetables and fruit—pasta and bread consumption, cake, sweets and chocolate, fish) and beverages. Intakes lower than once per week, but at least once per month, were coded 0.5 per week. Seasonal consumptions were also considered (weekly consumption of vegetables/fruits available in limited periods during the year, weighted for months of consumption). Energy and mineral, macro‐, and micronutrient intake were estimated using the most recent update of an Italian food consumption database (Gnagnarella et al., 2004). Body mass index (BMI) was classified according to World Health Organization (WHO) indications (World Health Organization, 2012). Men were considered as having risk factors for impaired fertility if they had a history of previous chemo‐ or radiotherapy, as well as previous reproductive organ diseases (ROD), such as orchiectomy, cryptorchidism, and varicocoele. These data were retrieved from clinical records. Smoking habits were categorized as never, former, or current, and number of cigarettes smoked daily and duration of smoking were recorded. Caffeine intake from coffee (60 mg per cup), cappuccino (75 mg per cup), tea (45 mg per cup), decaffeinated coffee (4 mg per cup), and chocolate (6 mg/10 g) was calculated (Tavani, 2013). Occupational physical activity (PA) was described as heavy (or very heavy), light/moderate, mainly standing or mainly sitting. Leisure PA was recorded in terms of hours/week: <2, 2–4, ≥5. No information was collected about intensity or type of leisure PA. Information on alcohol intake was collected as usual weekly consumption (1 unit = 125 mL wine or 330 mL beer or 30 mL spirits, all containing approximately 12.5 g of ethanol). An intake lower than one unit per week was coded as 0.5. The adherence to a Mediterranean diet was assessed through an a priori score (Mediterranean Diet Score, MDS), developed by Trichopoulou et al. (2003), modified for Italian dietary habits (Rosato et al., 2016) and specific for this population. It included nine components of diet: cereals (pasta and bread), legumes, vegetables, fruits, fish, monounsaturated (MUFA)/saturated fatty acids (SFA) ratio, meat (and meat products), dairy products, and alcohol intake. For each score component and for each study subject, a value of 0 or 1 was attributed: for components that are frequently consumed in the traditional Mediterranean diet (i.e., cereals, legumes, vegetables, fruit, fish, and high MUFA/SFA ratio), subjects were assigned a value of 1 if they had a consumption above or equal to the study‐specific median in the whole sample, and 0 otherwise; for components less frequently consumed (i.e., meat and dairy products), participants with a consumption lower than the study‐specific median were assigned a value of 1 and 0 otherwise. For alcohol intake, men consuming 10 g to less than 50 g of ethanol per day were attributed 1 point and 0 otherwise. The MDS was calculated by adding up the points for each of the nine individual components; thus, it varied between 0 and 9, and the higher the score the stronger the adherence to a Mediterranean diet. Sperm analysis Men were instructed to abstain from ejaculation for 2–5 days before semen analysis and to report the specific time of abstinence. Semen samples were obtained by masturbation and collected into a sterile plastic container provided and labeled with the date and time of collection. All seminal fluid examinations were carried out by the laboratory of the Unit where samples were maintained at room temperature until complete liquefaction. Duration of complete liquefaction (<1 h) was documented, until 1 h was reached. Semen analysis was performed with standardized methods according to the WHO guidelines (2010). The following variables were taken into consideration: volume (mL), sperm concentration (spermatozoa N/mL), and sperm motility (%). Sperm motility was classified into total (progressive + non‐progressive motility) and progressive motility. Total sperm count was calculated as volume × sperm concentration. Reference values from the WHO semen analysis manual were used to assess if sperm volume, concentration, total count, and motility (WHO guidelines, 2010) were normal or lower than the given levels: 1.5 mL for volume, 15 millions/mL for concentration, 39 millions for total count, and 32% for sperm motility. Men who had at least one recorded parameter were included in the analysis. According to the center procedure, if sperm concentration was lower than 1 million/mL, motility was not evaluated, as the couple was candidate to ICSI. As semen samples were collected specifically to carry out ART procedures, sperm morphology was only evaluated in partners of those couples undergoing IVF and after semen capacitation (and not on rough samples). Thus, this parameter, that was not routinely collected, was not analyzed. The laboratory personnel was trained using the European Society of Human Reproduction and Embryology (ESHRE) Special Interest Group in Andrology Basic Semen Analysis Course (Barratt et al., 2011). Statistical analysis Categorical or ordinal variables were described as frequency (%), and continuous variables as means (standard deviation, SD) if normally distributed or medians (interquartile range, IQR) if not. Three domains of semen quality were assessed as follows: volume, concentration, and total count, and they were analyzed in the present paper: low semen volume <1.5 mL; low sperm concentration <15 millions/mL; and low total sperm count <39 millions. We estimated the odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) in categories of MDS (i.e., 0–3, 4–5, and 6–9, approximate tertiles), and using the score as a continuous variable. To account for potential confounders, we included terms for variables associated with MDS or to each semen parameter in the unconditional logistic regression models: factors included in the model are indicated in the table footnotes. A second model included variables described as associated to semen variables in the literature. All the analyses were performed using the SAS software, version 9.4 (SAS Institute, Inc., Cary, NC, USA).

Results From September 2014 to December 2016, 347 men were interviewed; 327 (94.2%) had at least 1 seminal parameter measured. Among them, 18 (5.5%) did not provide complete information for MDS calculation and were excluded from the analysis. Men included in the analysis did not significantly differ from those excluded in terms of age, BMI, smoking, drinking habits and sperm parameters. Thus, the final analyses were conducted on 309 men, aged 39.3 years on average (SD 5.2, range 27–60): 59/306 (19.3%) had semen volume <1.5 mL, 92/302 (30.5%) had sperm concentration <15 mil/mL, and 96/299 (32.1%) had total count <39 mil. Prevalence was 45.6%, for overweight and 9.1% for obesity (BMI ≥ 30.0); 31.1% of men were current and 29.1% former smokers. Table 1 shows the median of intake for each component of the Mediterranean diet. Table 1. Mediterranean diet score Components of MDS Reference weekly intakea (servings) Point if intake < reference Point if intake ≥ reference Vegetables 12.0 0 1 Legumes 1.0 0 1 Fruits 18.7 0 1 Cereals 17.5 0 1 Fish 2.0 0 1 MUFA/SFA 1.55 0 1 Alcohol 50 g (predefined) 0 1 Red meat and meat products 6.5 1 0 Milk and dairy products 7.4 1 0 Table 2 shows the demographic characteristics and lifestyle habits of men, according to the MDS. In univariate analysis, MDS was significantly associated with smoking habits and leisure physical activity. Although no relationship was observed between MDS level and sperm parameters if considered as continuous variables, we found a positive relationship between MDS and proportion of men with normal sperm concentration and total count. A significant association was also observed between history of ROD and lower concentration and total count (data not shown in the tables). Age and education were unrelated with sperm characteristics, except for semen volume, that was more frequently normal in younger men (87.3% in <35, 85.4% in 35–39, and 73.4% in ≥40 years old, p = 0.011). Table 2. Demographic characteristics and lifestyle patterns of 309 men undergoing assisted reproduction technique, according to the presence of semen abnormalities Mediterranean diet score p 0–3 4–5 6–9 n = 86 27.8% n = 131 42.4% n = 92 29.8% Age (years) <35 21 24.4 21 16.0 14 15.2 35–39 28 32.6 56 42.7 39 42.4 ≥40 37 43.0 54 41.2 39 42.4 0.44 College degree 33 38.4 50 38.2 41 44.6 0.39 ROD 17 19.8 28 21.4 17 18.5 0.86 BMI <25.0 36 41.9 65 49.6 39 42.4 25.0–29.9 38 44.2 57 43.5 45 48.9 ≥30.0 12 14 8 6.1 8 8.7 0.62 Smoking Never 33 38.4 60 45.8 29 31.5 Current 27 31.4 45 34.4 24 26.1 Former 25 29.1 26 19.8 39 42.4 0.010 Leisure PA <2 h/week 43 50.0 61 47.0 23 25.0 2–4 h/week 23 26.7 45 34.0 41 44.6 ≥5 h/week 18 20.9 23 18.0 28 30.4 0.009 Daily calories (Kcal), median (IQR) 1850 1447–2218 1857 1626–2281 1987 1697–2331 0.08 Abstinence (days), median (IQR) 3 3–5 3 3–4 3 3–4 0.71 Infertility diagnosis Female factor only 32 37.2 53 40.5 39 42.4 Male factor only 24 27.9 35 26.7 22 23.9 Male and female factor 14 16.3 14 10.7 9 9.8 Unexplained 16 18.6 29 22.1 22 23.9 0.12 Previous ART cycles 48 55.8 69 52.7 59 64.1 0.25 Semen parameters (median, IQR) Volume (mL) (n = 306) 2.8 1.7–3.8 2.5 1.7–3.3 2.7 1.5–4.0 0.63 Volume < 1.5 (mL) 16 18.8 23 17.7 20 22.0 0.59 Concentration (*106 mil/mL) (n = 301) Median (IQR) 31.0 6.4–65.5 32.0 12.0–74.0 35.0 15.0–63.0 0.37 Concentration <15 (*106 mil/mL) 33 32.3 37 29.4 22 24.2 0.03 Total count (mil) (n = 298) Median (IQR) 68.4 16.8–159.1 84.0 29.9–162.8 80.5 38.2–138.6 0.35 Total count <39 (mil) 34 41.0 39 31.2 23 25.6 0.03 Table 3 illustrates the adjusted ORs of low semen volume, concentration, and total count, according to the MDS. No significant association with MDS emerged for low semen volume. On the contrary, for low concentration, as compared to the highest (6–9) category, lower adherence to MD was significantly associated with higher risk of low concentration and low total count. Results were consistent in both models. These findings were also observed in strata of ROD, although not always significant: in men without ROD history, OR by 1 MDS point decrease was 1.14 (95% CI 0.96–1.35) for low concentration and 1.20 (95% CI 1.01–1.43) for low total count. The corresponding estimates were 1.49 (95% CI 1.05–2.12) and 1.39 (95% CI 0.98–1.96) in men with history of ROD. Similar results emerged using the second model including age, BMI, days of abstinence, and daily calorie intake. Table 3. Odds ratios (OR) and 95% confidence intervals (CI) for the Mediterranean Diet Score Model 1 Model 2 0–3 4–5 0–3 4–5 MDS 6–9 (reference category) AOR (95% CI) AOR (95% CI) AOR (95% CI) AOR (95% CI) Volume < 1.5 mL 0.87 (0.40–1.91) 0.71 (0.34–1.47) 0.95 (0.42–2.14) 0.75 (0.35–1.60) Chi‐square for trend = 0.12, p = 0.73 Chi‐square for trend = 0.02, p = 0.89 By 1 MDS point 0.96 (0.81–1.15) 0.98 (0.82–1.19) Concentration <15*106 mil/mL 2.42 (1.21–4.83) 1.34 (0.69–2.50) 2.61 (1.26–5.42) 1.44 (0.72–2.88) Chi‐square for trend = 6.44, p = 0.011 Chi‐square for trend = 6.78, p = 0.009 By 1 MDS point 1.20 (1.03–1.39) 1.24 (1.05–1.45) Total count <39*106 mil 2.08 (1.05–4.12) 1.26 (0.66–2.42) 2.24 (1.09–4.58) 1.46 (0.74–2.46) Chi‐square for trend = 4.49, p = 0.034 Chi‐square for trend = 4.91, p = 0.027 By 1 MDS point 1.23 (1.06–1.43) 1.24 (1.06–1.46) A sensitivity analysis was performed, including only men with complete information about sperm parameters (n = 298, model 2). AOR for low semen volume was 1.04 (95% CI 0.46–2.38) and 0.83 (95% CI 0.38–1.80) for MDS 0–3 and 4–5, respectively (chi‐square for trend 0.01, p = 0.91). AOR by 1 MDS point was 1.01 (95% CI 0.84–1.22). AOR for low sperm concentration was 2.50 (95% CI 1.20–5.20) for MDS 0–3 and 1.36 (95% CI 0.68–2.73) for MDS 4–5 (chi‐square for trend 6.12, p = 0.013); AOR by 1 MDS point was 1.23 (95% CI 1.04–1.44). AOR for total sperm count was 2.24 (95% CI 1.09–4.58) for MDS 0–3 and 1.46 (95% CI 0.74–2.86) for MDS 4–5 (chi‐square trend 4.91, p = 0.027); AOR by 1 MDS point was 1.24 (95% CI 1.06–1.46). This sensitivity analysis confirmed the findings of the whole sample.

Discussion By using a simple, intuitive and frequently used dietary score to assess compliance to the Mediterranean diet, this cross‐sectional analysis found that adherence to the Mediterranean dietary pattern is related to a diminished risk of low sperm concentration and total count. This association was particularly marked in men with history of ROD: however, given the low number of men in this group, this finding remains to be confirmed. The present results are in broad agreement with previous reports on men from Fertility clinics. In a recent paper, Karayiannis et al. (2017) compared men in the highest tertile of the MedDietScore with men in the lowest tertile: Using the WHO reference values, they found that a higher percentage in the lowest tertile showed lower sperm concentration (47.4% vs. 16.7%), total sperm count (55.3% vs. 22.7%), total motility (65.8% vs. 31.8%), progressive motility (84.2 vs. 62.1%), and normal sperm morphology (50.0 vs. 28.8%). In the multivariable adjusted models, men in the lowest tertile of the MedDietScore had about 2.6 times higher likelihood of having abnormal sperm concentration, total sperm count, and motility, compared to men in the highest tertile of the score. Our results showed a similar level of positive association between MDS and sperm parameters, although we were not able to analyze motility and morphology. Interestingly, as in our sample, sperm parameters were not significantly associated if analyzed as continuous variables. In a group of men from a Fertility clinic, Eslamian et al. (2017) identified 2 dietary patterns: a “prudent pattern” (including several types of vegetables, fish and seafood, fruits, vegetable oils) similar to the Mediterranean diet and a “Western pattern” (organ meats, red and processed meats, sugar, soft drinks, refined grains, potatoes, French fries, high‐fat dairy products, hydrogenated fats). After adjustment for potential confounders, participants in the highest tertile of the prudent pattern scores had 54% lower risk of asthenozoospermia compared to those in the lowest one. Lastly, Oostingh et al. (2017) enrolled 129 male partners of pregnant women who participated in the Rotterdam Periconception Cohort: A strong adherence to the healthy dietary pattern, identified by high intakes of cereals, fruits, legumes, vegetables, and olive oil, was positively associated with better sperm concentration, total count, and motility. With reference to young healthy males, Cutillas‐Tolín et al. (2015) identified two dietary patterns in a sample aged 18–23 years: the Western pattern was characterized by high consumption of processed meat, French fries, and snacks, and the Mediterranean pattern was characterized by high consumption of seafood, vegetables, and fruit. The Western pattern was inversely associated with total sperm count (although this finding was limited to a subgroup of obese men), whereas the Mediterranean pattern showed a positive relationship (P for trend = 0.04) with this parameter. In another study on young healthy men (Gaskins et al., 2012), the “Prudent” pattern, characterized by high intake of fish, chicken, fruit, vegetables, legumes, and whole grains, was positively associated with percent progressively motile spermatozoa. Men in the highest quartile of the Prudent diet had higher progressively motile spermatozoa compared with men in the lowest quartile. Dietary patterns were also investigated in 7282 Chinese healthy males in Taiwan (Liu et al., 2015): in this study, Healthy diet was characterized by high intakes of vegetables and fruits, but it was not associated with any sperm parameter. The authors suggested that environmental contaminants in fruits and vegetables could cause a lower semen quality, thus explaining the inconsistence between their findings and previous results: to support this hypothesis, a paper by Chiu et al. (2015) reported that high intake of high pesticide residue fruits and vegetables was associated with fewer morphologically normal spermatozoa, and lower concentration and total motility count. Thus, low semen quality parameters were inversely associated with healthy diets, that included high intake of some nutrients, such as some antioxidants (selenium, zinc, cryptoxanthin, lycopene, β‐carotene, vitamin E, vitamin C), other vitamins (vitamin D and folate), and omega‐3 FA, and low intake of SFA and trans‐FA (Salas‐Huetos et al., 2017). Several food groups, such as cereals, vegetables and fruits, poultry, low‐fat dairy and skimmed milk, fish, shellfish, and seafood, were positively associated with sperm quality parameters. The Mediterranean diet is characterized by high intake of fruits and vegetables, associated with better sperm characteristics through their contents in antioxidants and folates. A low folate concentration in seminal plasma is associated with sperm DNA damage, as folates are involved in DNA synthesis and in DNA and protein methylation processes. Due to the mis‐incorporation of uracil instead of thymine, folate shortage increases DNA fragility. When the removal of the mis‐incorporated uracil fails, double‐strand breaks resulting in chromosome instability may occur during normal repair processes. Folate shortage also decreases the supply of methyl groups, which are important substances for the protection of DNA against harmful exposures (Boxmeer et al., 2007). Antioxidants are known to scavenge and dispose of reactive oxygen species (ROS), suppress their formation, and also act to oppose the actions of ROS. The dietary intake of antioxidants has been associated with semen quality, and men with higher intake of antioxidants, both dietary and supplementary, may have less DNA damage in their spermatozoa (Schmid et al., 2012). However, a Cochrane meta‐analysis (Showell et al., 2014) concluded that randomized controlled trials of antioxidants vs. placebo did not consistently show an effect of 3‐, 6‐, or 9‐month treatment on semen parameters. It is possible that this kind of diet was associated with a generally healthy lifestyle, with an overall positive effect on semen quality. Several limitations exist in the current study. The information regarding diet was self‐reported; thus, some misclassification may have occurred. Moreover, the cross‐sectional design does not allow to assess possible dietary changes occurred in the past. The semen samples were collected on the day of oocyte retrieval: this may be cause of a potential bias. In fact, before patients underwent ART, previous semen samples for infertility diagnosis were collected; thus, patients were aware of their semen quality before undergoing ART, and they should know whether IVF or ICSI was performed. Consequently, patients who had poor semen quality may over‐report having an unhealthy diet or underreport healthier diet. Otherwise, information on dietary habits was based on a validated and reproducible FFQ (Franceschi et al., 1993, 1995; Decarli et al., 1996). Further, recommendations against or in support of specific foods for fertility preservation are not routinely advocated. Even regarding alcohol, in Italy, its consumption is socially accepted and not advised against during assisted reproduction procedures, and information was satisfactorily valid (Ferraroni et al., 2004). On the contrary, underreporting of cigarette consumption was possible, due to a low social acceptability of smoking (Gallus et al., 2011). However, an underreporting should tend to reduce the estimated association between alcohol and semen parameters. According to the paper by Chiu et al. (2017), within‐patient variability over time was substantial, and a single semen sample may not suffice to correctly classify men as normal according to WHO reference limits. In our sample, comparing diagnosis of men's infertility and classification based on the single sample taken for ART procedure, we found that out of 191 men without infertility diagnosis, 39 (20.4%) had at least one parameter below WHO limit. Considering that infertility diagnosis was, in some cases, due to low motility or abnormal morphology (parameters not included in the present analysis), the single semen sample identified most men with fertility problems: moreover, in the present analysis, any misclassification would lower the association with MDS. As regards sperm analysis, a limitation of this study was that Makler counting chamber is used in our laboratory, despite its accuracy having been debated in the literature. However, it has to be mentioned that our procedures are highly standardized and that the laboratory is involved in an External Quality Control program. Any misclassification should tend to lower the investigated associations. An important limitation is that our findings should be referred only to men of infertile couples. Lastly, the possibility of unmeasured confounding is another limitation of this study. Among the strengths of this study, there is its relatively large sample size, which is even more relevant as this is a single institution study. Men were interviewed in the same Institution by the same personnel, and participation was practically complete. Moreover, we analyzed the role of Mediterranean diet in men with or without other conditions associated with infertility. We also could account for potential confounders, such as age, smoking, BMI, calorie intake, days of abstinence, that have been previously reported to be associated with semen quality (Li et al., 2011). In conclusion, in this cohort of male partners of sub fertile couples undergoing ART cycles, we found that Mediterranean Diet Score is positively associated with normal sperm concentration and total count, but not with semen volume. Considering the design of this study, we cannot establish a causal relation between adherence to Mediterranean diet and better semen quality, particularly since these findings may reflect generally healthier lifestyle habits, despite our careful allowance for smoking and other potentially relevant covariates.

Acknowledgments We are indebted to Marta Castiglioni, Benedetta Gallotti, and Marco Reschini for their valuable contribution to data collection and patients’ counseling.

Conflict of Interest The authors have no competing financial interest to declare.

Authors’ Contribution FP and ILV were involved in conceptualization of the study; FP and CLV performed methodology of the study; SF, MC, and VDC performed validation; ER and FB carried out formal analysis; SN, MC, and SF investigated the study; VDC, SF, and SN were involved in data curation; ER and FP were involved in writing—original draft preparation; CLV, FB, and SN were involved in writing—review, and editing of the manuscript.

Supporting Information Filename Description andr12587-sup-0001-TableS1.docxWord document, 11.9 KB Table S1 Median values of sperm parameters according to Mediterranean Diet Score. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.