By: Andrea Nguyen
Editor’s Note: Starting today, FACTS is celebrating Men’s Health Month with a 3-week series on topics relevant to male fertility. The series opens with a systematic review by Salas-Huetos et al [1] on the role of food and nutrition in male fertility. Andrea Nguyen summarized the study’s findings during her last year in medical school while enrolled in the popular FACTS elective on fertility awareness. Andrea is one of more than a thousand students who learned about the evidence behind fertility awareness-based methods (FABMs) through the FACTS elective and can now teach their patients and colleagues! Our series on male fertility continues June 16th with a review of a potential solution to cases of idiopathic male infertility. On June 23rd, the article reviewed highlights ways to diagnose and treat infertility caused by antisperm antibodies.
Introduction
Infertility is defined as the inability to achieve a successful pregnancy after at least 12 months of regular intercourse. Infertility remains a global health issue that affects 15% of all couples of reproductive age, with male factors contributing to approximately 30-50% of cases. [2] Previous studies suggest semen quality has declined in Europe and the USA, but the underlying causes are not well understood. Many factors have been considered, including the environment, genetics, oxidative stress, physiological factors, and diet. The study by Salas-Huetos et al [1] summarized below aimed to investigate the impact of diet and nutrients on sperm function and fertility. By reviewing observational studies about this topic, the authors sought to enhance understanding of infertility and its relationship to male reproductive health.
“Infertility remains a global health issue that affects 15% of all couples of reproductive age, with male factors contributing to approximately 30-50% of cases.” [2]
Methodology
The authors conducted a systematic review of published literature from the earliest available online indexing year until November 2016. Articles were screened for eligibility, ensuring clear definitions of male fertility and infertility and inclusion of primary outcome measures related to semen quality or fecundability. Data from eligible articles were extracted and evaluated using a six-point scale that included: study participation, study attrition, prognostic factor measurement, confounding measurement and account, outcome measurement, and analysis. Studies scoring more than 3 to 6 were deemed high quality and were subject to more in-depth analysis.
Results
A total of 1,944 records were identified based on the search criteria. Abstracts were screened to assess if they met inclusion criteria, and the full text of remaining articles was analyzed for suitability. In the end, 35 articles were included for qualitative analysis, comprising research of men aged 18 to 80 from 18 countries worldwide and various study types (cross-sectional, case-control, prospective, and retrospective studies).
A summary of findings from the 35 studies analyzed indicates healthy diets rich in omega-3 fatty acids, antioxidants (vitamins E, C, β-carotene, selenium, zinc, cryptoxanthin, and lycopene), vitamins D and folate, and low in saturated and trans-fats were associated with better semen quality. Foods with a positive influence on sperm quality included fish, shellfish, seafood, poultry, whole grains, vegetables, fruits, low-fat dairy, and skim milk. In contrast, diets high in processed meat, soy foods, potatoes, full-fat dairy, cheese, coffee, alcohol, sugar-sweetened beverages, and sweets were linked to lower semen quality. Regarding fecundability, high consumption of alcohol, caffeine, red meat, and processed meats negatively impacted pregnancy chances or fertilization rates in their partners.
“Foods with a positive influence on sperm quality included fish, shellfish, seafood, poultry, whole grains, vegetables, fruits, low-fat dairy, and skim milk.”
Discussion
These results suggest dietary choices can have significant impact on male fertility, including semen quality and fecundability. This information is relevant for couples trying to conceive because in addition to using fertility awareness-based methods (FABMs), men can optimize their reproductive health by becoming more aware of their dietary habits, and modifying them as needed. By encouraging patients to be more mindful of their nutrient intake, medical professionals can support men in enhancing their potential fertility to improve the likelihood of pregnancy for the couple.
“By encouraging patients to be more mindful of their nutrient intake, medical professionals can support men in enhancing their potential fertility to improve the likelihood of pregnancy for the couple.”
Although this systematic analysis highlights the role diet can play in fertility, it would also be interesting to consider other factors that influence male fertility. These could include overall health status, age, body weight, medication use, physical activity levels, occupation, environmental, genetic, and lifestyle factors.
Strengths of this study include its comprehensive analysis and review of the available literature. The review included studies from diverse global populations, and the consistent findings reinforce their reliability and generalizability. However, the study also has some limitations. Some publications could have been misclassified or may not have been identified and inadvertently excluded despite meeting the study’s inclusion criteria.
Additionally, since the studies analyzed were observational studies, they establish associations, not causation, between diet and male fertility. Furthermore, the other potential factors mentioned above (overall health status, age, body weight, medication use, physical activity levels, occupation, environmental, genetic, or lifestyle factors) were not addressed in the study and could act as potential confounders. Therefore, more high-quality studies are needed to establish stronger relationships between food and nutrients and semen quality and fecundability, including randomized control trials and larger cohort studies.
Conclusion
The results of the systematic review by Salas-Huetos et al [1] suggest that adherence to a healthy diet and adequate nutrient intake could potentially improve semen quality and fecundability. Future research exploring diet could provide a more comprehensive understanding of male fertility and contribute to more holistic approaches to male reproductive health.
Editor’s Note: Learn more about male infertility in the reviews below, all written by medical students on the FACTS elective. If you would like to help educate our students and residents on the elective, please follow the link and apply to be a clinical preceptor for FACTS!
- Treatment Options for Male Infertility: A Brief Review
- Infertility as a Proxy of Male Health: A Review of Research
- Men’s Knowledge of Infertility and Related Risk Factors: A Review of Research
References
[1] Salas-Huetos A, Bulló M, Salas-Salvadó J. Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies. Hum Reprod Update. 2017;23(4):371-389. doi:10.1093/humupd/dmx006
[2] Eisenberg ML, Esteves SC, Lamb DJ, et al. Male infertility. Nat Rev Dis Primers. 2023;9(1):49. Published 2023 Sep 14. doi:10.1038/s41572-023-00459-w
ABOUT THE AUTHOR
Andrea Nguyen
Andrea Nguyen is a fourth-year medical student at Kansas City University in Kansas City, MO. She is passionate about advancing health equity and empowering underserved and historically marginalized communities. She enrolled in the FACTS elective to deepen her understanding of FABMs and explore their role in lifestyle-based health strategies.
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