For Healthcare Professionals Only

Fertility discussions often begin with a focus on female reproductive health, yet it is now well established that male factors contribute to approximately 50% of all infertility cases. Male fertility is not a static metric; it can fluctuate based on a variety of biological and environmental influences. As healthcare professionals, it’s essential to recognise the dynamic nature of spermatogenesis and the critical role that nutrition, particularly selenium, can play in supporting sperm health.

Sperm Health Is Not Fixed

Sperm is produced in a continuous cycle, with a full spermatogenic cycle taking approximately 74 days. This means the sperm profile can vary significantly over time. While a semen analysis might show normal parameters at one point, a new cohort of sperm formed in the following months may present differently, especially if there are ongoing lifestyle or environmental challenges. Semen analysis typically assesses concentration, motility, morphology, and DNA integrity. Even when basic parameters appear within normal ranges, subclinical oxidative stress can still impair sperm function and compromise fertility outcomes. Moreover, studies have shown a correlation between abnormal semen parameters and an increased risk of miscarriage, highlighting the importance of sperm quality in early embryonic development and pregnancy viability [1].

The Impact of Stress and Lifestyle

Psychological stress is another important variable. It is now understood that stress can negatively affect both male and female fertility, and its impact on male reproductive hormones and spermatogenesis is well documented [2]. Modifiable lifestyle factors including diet, smoking, alcohol intake, body weight, and exposure to environmental toxins are all critical considerations when supporting men trying to conceive.

Nutrition and Sperm Health: The Role of Selenium

Selenium is an essential trace mineral with powerful antioxidant properties, and it plays a particularly important role in male reproductive physiology. It is required for the formation and function of selenoproteins, many of which are involved in protecting sperm from oxidative damage during spermatogenesis.

Key Mechanisms of Action

• Antioxidant protection: Sperm membranes are rich in polyunsaturated fatty acids, making them especially vulnerable to oxidative stress. Selenium is a cofactor for glutathione peroxidase, an enzyme that helps prevent lipid peroxidation in sperm cells.
• Spermatogenesis: Selenium supports the differentiation and maturation of spermatogonia into motile, morphologically normal sperm. Deficiency has been linked to reduced sperm count, poor motility, and impaired morphology [3].
• Environmental protection: Selenium may also offer protection against reproductive toxicity induced by heavy metals such as cadmium and lead, which are known to disrupt testicular function.

Dietary Sources and Supplementation

Selenium is found in a range of foods including seafood, lean meats, grains, onions, garlic, and Brazil nuts. Brazil nuts are especially rich in selenium, with just 4–6 nuts daily providing well over the recommended daily intake. While food-first strategies are ideal, supplementation may be appropriate for men with documented deficiency or those undergoing fertility treatment.

Combining selenium with other antioxidants, most notably vitamin E, has shown synergistic effects in improving sperm motility and reducing DNA fragmentation in several clinical studies.

Clinical Recommendations

• Preconception timing: Encourage men to optimise their nutrition at least 3 months prior to conception attempts to support the full cycle of spermatogenesis.
• Dietary intake: Advise the inclusion of selenium-rich foods in the daily diet, particularly Brazil nuts (with attention to portion control to avoid excess intake).
• Supplementation: Consider supplementation in those with inadequate dietary intake, especially when semen parameters are suboptimal or oxidative stress is suspected.
• Lifestyle support: Address smoking cessation, stress management, and environmental toxin avoidance alongside nutritional interventions.

Conclusion

Sperm health is a dynamic and sensitive marker of male reproductive function. Optimising preconception nutrition, particularly through adequate selenium intake, is a simple but impactful strategy to support male fertility. For HCPs, integrating nutritional assessment and advice into fertility care can significantly enhance patient outcomes improving not only the chances of conception but also the health of the future child.

References

1. Aitken RJ, Smith TB, Jobling MS, Baker MA, De Iuliis GN. Oxidative stress and male reproductive health. Asian J Androl. 2014 Jan-Feb;16(1):31-8. doi: 10.4103/1008-682X.122203. PMID: 24369131; PMCID: PMC3901879.
2. Janevic T, Kahn LG, Landsbergis P, Cirillo PM, Cohn BA, Liu X, Factor-Litvak P. Effects of work and life stress on semen quality. Fertil Steril. 2014 Aug;102(2):530-8. doi: 10.1016/j.fertnstert.2014.04.021. Epub 2014 May 23. PMID: 24856463; PMCID: PMC4382866.
3. Hawkes WC, Turek PJ. Effects of dietary selenium on sperm motility in healthy men. J Androl. 2001 Sep-Oct;22(5):764-72. PMID: 11545288.