Role of Mediterranean Diet and Ultra-Processed Foods on Sperm Parameters: Data from a Cross-Sectional Study

Abstract

Background/Objectives: Male infertility is multifactorial, involving genetic, environmental, lifestyle, and medical factors. Recent research has underscored the influence of lifestyle choices, such as dietary habits, smoking, alcohol abuse, and metabolic disturbances, on sperm quality. In this context, nutrition plays a pivotal role: adherence to a healthy diet like the Mediterranean Diet (MD), which emphasizes seasonal, fresh, and whole foods, has been linked to improved sperm performance. Conversely, a high intake of ultra-processed foods (UPFs), characterized by additives, high levels of sugars, fats, and salt, and a nutrient-poor profile, may impair sperm quality. Methods: Based on data supporting the reproductive health benefits of the MD, this observational cross-sectional study aimed at evaluating the possible relationship between MD adherence, assessed using the 14-point a priori Mediterranean Diet Adherence Screener (MEDAS) and intake of ultra-processed foods (UPFs), based on the NOVA classification, and sperm quality in 358 individuals (mean age 34.6 ± 9.3 years) who spontaneously referred to our center of reproductive medicine. Semen analyses were performed according to the WHO 2021 criteria. Hormonal profiles (FSH, LH, testosterone, SHBG, bioavailable testosterone, and calculated free testosterone) were also determined. Results: MD adherence score was significantly and positively correlated with semen parameters, whilst negatively correlated with FSH and LH levels. In contrast, UPF intake was correlated with poor semen parameters, whilst no association was observed with hormonal levels. Multivariate analyses confirmed these associations and showed the independency from age and BMI. Notably, among men with FSH levels < 8 IU/mL, higher quartiles of UPF intake had lower markers of sperm quality, particularly for viability and typical morphology. Differently, high MD adherence scores were associated with high quality sperm parameters even when FSH levels were >8 IU/mL. Conclusions: This study provides evidence that the adherence to MD, and conversely reduced intake of ultra-processed foods, is associates with a better semen profile. These findings suggest the possible role of dietary interventions as a modifiable factor in the management of male infertility.

Keywords: Mediterranean diet; diet; fertility; infertility; nutrients; nutrition; sperm parameters; ultra-processed food.

Figure 1

Effect of adherence to the Mediterranean diet, categorized by MEDAS score into low (1), moderate (2), and high adherence (3), on seminal (A) and hormonal parameters (B). FSH: follicle-stimulating hormone; LH: luteinizing hormone; TT: total testosterone; SHBG: sex hormone-binding globulin; BAT: bioavailable testosterone; fT: calculated free testosterone. The p-values associated with the comparison between pairs of groups are specified in the image.

Figure 2

Effect of ultra-processed food consumption, assessed using the “24-h Food Recall Questionnaire” and categorized into low (Q1), medium-low (Q2), medium-high (Q3), and high consumption (Q4), on seminal (A) and hormonal parameters (B). FSH: follicle-stimulating hormone, LH: luteinizing hormone, TT: total testosterone, SHBG: sex hormone-binding globulin, BAT: bioavailable testosterone, fT: calculated free testosterone, %Kal-UP: percentage of calories derived from ultra-processed foods. The p-values associated with the comparison between pairs of groups are specified in the image.

Figure 3

Comparison of seminal and hormonal parameters between subjects with low adherence to the Mediterranean diet (MEDCat1) and high consumption of ultra-processed foods (Q4) and subjects with high adherence to the Mediterranean diet (MEDCat3) and low consumption of ultra-processed foods (Q1) (respectively 0 and 1 conditions in the plot). FSH: follicle-stimulating hormone, LH: luteinizing hormone, TT: total testosterone. The p-values associated with the comparison between pairs of groups are specified in the image.

Figure 4

Evaluation of the interaction between gonadotropin levels, expressed as a dichotomous variable (FSH < 8 IU/mL and FSH ≥ 8 IU/mL), and the consumption of UPFs, categorized into low (Q1), medium-low (Q2), medium-high (Q3), and high consumption (Q4), on sperm parameters. FSH: Follicle-stimulating hormone. p-values associated with pairwise group comparisons are specified in the image.

Figure 5

Evaluation of the interaction between gonadotropin levels, expressed as a dichotomous variable (FSH < 8 IU/mL and FSH ≥ 8 IU/mL), and MEDAS value categorized into low (Medcat1), medium (Medcat2), and high adherence (Medcat3), on seminal parameters. FSH: Follicle-stimulating hormone. The p-values associated with pairwise group comparisons are specified in the image.

Figure 6

Representative scheme summarizing the possible mechanistic influences of dietary patterns on spermatogenesis. Adherence to Mediterranean diet (MD) likely has a direct positive effect on the different cell populations of the seminiferous tubules due to its composition rich in polyunsaturated fatty acids and oligo-elements. In parallel, MD might positively influence the hypothalamic-pituitary-gonadal axis by improving testis sensitivity to follicle-stimulating hormone (FSH) or by reducing the negative feedback at central level. Ultra-processed food intake negatively influences testis function by both being inversely related to MD adherence and because of the reduced content of protective factors. Green and red arrows indicate, respectively, positive and negative effects.