FACTS Men’s Health Series
The Effect of Nutrients and Dietary Supplements on Sperm Quality Parameters
By Carley Warner
Editor’s Note: To mark National Men’s Health Month, we will be highlighting a series of research studies that examine men’s reproductive wellbeing, factors that might affect infertility and the effectiveness of various treatments. Carley Warner, a medical student who participated in the FACTS elective, summarized a 2018 meta-analysis published in Advances in Nutrition of more than two dozen randomized clinical trials that assessed factors affecting sperm quality.
Infertility is a global health concern, according to the World Health Organization (WHO), impacting about 15% of the population. In a 2017 meta-analysis about trends in sperm count, Levine et al. found between 1973 and 2011, there was a steady and significant decline in global sperm counts. The data may suggest an overall decline in male fertility, which could have implications for reproductive health and population growth in the future. Research into what might affect sperm count is strongly warranted.
Diet, exercise, alcohol use, tobacco use, and substance abuse are some of the main sources of the decline in fertility, according to some prior observational studies. One suggested that adhering to a Mediterranean diet, for example, could improve sperm quality and production . However, observational studies alone are not adequate, and randomized clinical trials (RCT) are considered the gold standard for drawing evidence-based conclusions. The aim of this systematic review was to determine the effects of nutrients and supplements on sperm quality parameters, primarily sperm motility, vitality and DNA damage.
The researchers selected relevant studies to include in the meta-analysis by searching keywords related to male infertility, diet, and nutrition. To be included, the RCT study had to clearly identify the fertile or infertile status of the male participants. Additionally, sperm quality had to be characterized by semen volume, ejaculate pH, total sperm count or concentration, sperm vitality, sperm motility (progressive or total motility), sperm morphology, acrosome resistance, sperm DNA fragmentation (SDF) or damage, sperm chromatin integrity, sperm reactive oxygen species (ROS), sperm aneuploidies, sperm function parameters, or hormonal levels.
A total of 28 studies were included for qualitative analysis and 15 studies were quantitatively analyzed. The study participants, ages 18 to 52, spanned 11 different countries. Antioxidant supplements, folic acid and/or zinc, omega-3 fatty acids, CoQ10 supplements, carnitine, and other dietary supplements were assessed in at least one of the 28 included studies. All studies, however, evaluated sperm parameters and quality.
In the quantitative analysis, supplementation with selenium of 100-300 µg/day for 3-11 months was shown to improve sperm motility, total concentration and morphology. Supplementation with zinc 66-500 mg/day for 3-6 months was also shown to improve total motility and sperm concentration. However, folic acid supplementation at 5 mg/day for 3-6 months did not result in improvement in sperm concentration, total motility, or morphology. Supplementation with omega-3 fatty acid that contains at least 1g of DHA and 1g of EPA for 10-32 weeks was shown to improve sperm count, concentration, morphology, and total motility. In addition to those meta-analyses, four randomized clinical trials were included that demonstrated CoQ10 supplementation of 200-300 mg/day for 3-6 months improved total sperm count, sperm concentration, motility, and morphology. Lastly, carnitine supplementation of 3g/day for 2-6 months was likewise shown to improve sperm motility and morphology, although with no improvement in sperm concentration.
The meta-analysis performed included several RCTs that suggested a beneficial effect of certain supplements on male infertility as determined by sperm count, concentration, motility, and morphology.
“Male infertility is often multifactorial, but oxidative stress has been implicated as one of the main causes.”
Male infertility is often multifactorial, but oxidative stress has been implicated as one of the main causes. This stress is connected with increased cellular damage and can cause sperm dysfunction. DNA damage, in turn, can increase oxidative stress by inducing the production of more reactive oxygen species. Balancing the reactive oxidative stress and benefits of antioxidants is important to maintain healthy sperm and fertility.
Several supplements were beneficial in improving the live birth rate among couples with male infertility or unexplained subfertility. Other supplements studied showed improvement in sperm parameters but did not demonstrate a positive effect on birth rate, however. Selenium, zinc, omega-3 fatty acids, CoQ10 were shown to have positive effects on different parameters. Selenium is required for spermatogenesis in mammals, and zinc inhibits oxidative enzyme-mediated cellular stress. Omega-3 fatty acids have anti-inflammatory properties and may aid in the lipid membrane of spermatozoa. CoQ10 is an important enzyme in the electron transport system which is utilized in the production and processing of reactive oxygen species. Carnitine is an important energy-storage molecule that provides immediately accessible energy for spermatozoa. Based on the evidence in this analysis, the different supplements had varying positive effects.
- Omega-3 fatty acids and CoQ10 improved total sperm count.
- Selenium, zinc, CoQ10, and omega 3’s were beneficial for sperm concentration.
- Selenium, zinc, omega 3’s, CoQ10, and carnitines improved sperm motility.
- Selenium, omega 3’s, CoQ10, and carnitines were beneficial for sperm morphology.
- Vitamin E and zinc improved live birth rates.
A systematic review of randomized clinical trials and meta-analysis can be helpful in determining whether to use supplements to improve male fertility and sperm quality. Based on this review, selenium, zinc, omega-3 fatty acids, CoQ10, carnitines, or a diet rich in these nutrients can improve sperm count, concentration, and motility. More randomized clinical trials with large sample sizes are needed, as well as more clear inclusion and exclusion data. Male infertility impacts many couples worldwide, and modifiable risk factors — such as diet, exercise, tobacco use, alcohol intake, and drug use — might directly affect that. As the researchers laid out, certain supplements and dietary changes might benefit males struggling with infertility, but further research is needed.
 Salas-Huetos A, Rosique-Esteban N, Becerra-Tomás N, Vizmanos B, Bulló M, Salas-Salvadó J. The effect of nutrients and dietary supplements on sperm quality parameters: a systematic review and meta-analysis of randomized clinical trials. Adv Nutr 2018;9:833–848. doi: 10.1093/advances/nmy057.
 Levine H, Jørgensen N, Martino-Andrade A, Mendiola J, Weksler-Derri D, Mindlis I, Pinotti R, Swan SH. Temporal trends in sperm count: a systematic review and meta-regression analysis. Hum Reprod Update 2017; 23:646-59.
 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;23:371–89
ABOUT THE AUTHOR
Carley Warner recently completed medical school at Kansas City University College of Osteopathic Medicine. She plans to become an obstetrician gynecologist. She has always loved women’s health and being able to empower women to gain a better understanding of their bodies and take control of their health. She is excited to be able to educate and offer her future patients the option to use fertility awareness-based methods and help them seek the care and education that is right for them.