These are the results of an analysis of 28 nutritional intervention studies involving 2900 participants and headed by the Universitat Rovira i Virgili. These supplements may increase male fertility

Infertility affects 15% of the world population and is recognised by the World Health Organisation as a global health problem. In recent years, studies of sperm quality in different populations from developing countries have shown a decrease that could have consequences for the survival of the human species. The decrease in sperm quality has been related to unhealthy lifestyles. Stress, the consumption of drugs, tobacco and alcohol and unhealthy diets seem to be the principal modifiable factors.

Despite the current lack of scientific evidence regarding the effect of dietary and nutritional supplements on sperm quality, many fertility clinics offer dietary recommendations and supplements before providing their patients with in-vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI).

Recently, researchers at the Human Nutrition Unit of the Universitat Rovira i Virgili (URV) and the Pere i Virgili Health Research Institute (IISPV), which are both members of the Ciber Obn Network of the Carlos III Institute, and researchers at the Clinical Department of Human Reproduction and Infant Growth at the Universidad de Guadalajara (Mexico) have carried out the most extensive and systematic review to date of randomised clinical studies into the effects of different nutrients and dietary supplements on sperm quality and male fertility.

After qualitatively analysing the results of 28 nutritional studies involving 2900 participants, researchers have concluded that supplementing the diet with omega 3 and coenzyme Q10 (in either liquid or tablet form) can have a beneficial effect on the quantity of spermatozoids in semen. Supplementing the diet with selenium, zinc, fatty acids, omega-3 and coenzyme-Q10 is associated with an increase in spermatozoid concentration; supplementing the diet with selenium, zinc, omega-3, coenzyme-Q10 and carnitines has been associated with an improvement in sperm mobility, and finally, selenium, fatty acids, omega-3, coenzyme-Q10 and carnitines has a positive effect on the morphology of spermatozoids.

According to the researchers, their study suggests that dietary supplements have a modulating effect on sperm quality and provides an extensive and up-to-date review of the existing scientific evidence. The results suggest that certain dietary supplements can have a beneficial effect on sperm quality, although it remains to be demonstrated whether this increases the likelihood of conceiving a child naturally or through assisted reproduction techniques. The researchers believe that further studies need to be carried out with larger samples so that a more accurate conclusion can be drawn.

The results of the present study, headed by Albert Salas-Huetos, post-doctoral researcher currently at the University of Utah and Jordi Salas-Salvadó, professor and director of the Human Nutrition Unit at the URV, have been published in the November edition of the  scientific journal Advances in Nutrition.

Reference: 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. Advances in Nutrition, 2018; 9(6), 833-848. DOI:  10.1093/advances/nmy057.