Nut consumption improves sperm count, motility
Adding nuts to a regular diet resulted in improved semen quality and sperm functional parameters among healthy men, according to a study presented at ESHRE 2018.
This randomized, parallel study comprised 119 healthy young males aged 18–35 years who were instructed to follow a Western-style diet, either nut-free or supplemented with a mixture of almonds, hazelnuts, and walnuts (60 g/day). Sperm and blood samples were collected and evaluated at baseline and 14 weeks. [ESHRE 2018, abstract O-238]
At week 14, participants who incorporated nuts into their diet had significant improvements in their sperm count (p=0.0043), vitality (p=0.0027), total motility (p=0.0093), progressive motility (p=0.0207), and morphology (p=0.0073), as well as a significant reduction in sperm DNA fragmentation (p=0.0018), compared with those who did not.
DNA fragmentation is believed to be caused by oxidative stress brought about by environmental and lifestyle factors, while the decline in sperm quality and quantity has been attributed to pollution, smoking, and a trend toward a Western-style diet in industrialized countries. [Hum Reprod Update 2017;23:646-659]
“Our findings support a beneficial role of chronic nut consumption in sperm quality and explore the molecular mechanism that could explain our results,” said Dr Albert Salas-Huetos from the Human Nutrition Unit of the Universitat Rovira i Virgili in Reus, Spain.
The sperm parameters and DNA fragmentation are all closely tied to male infertility, said Salas-Huetos. “At the molecular level … the genetic integrity of each sperm cell is essential for successful fertilization. If DNA strands in the cell become damaged or fragmented, they will be unable or less likely to fertilize an egg and maintain embryonic development.”
However, as the study only included healthy and fertile subjects following a Western-style diet, the results cannot be extrapolated to the general population, he pointed out. It would also be too early to state that adding nuts to a daily diet would aid in conception (natural or IVF) despite the growing literature demonstrating its benefits. “Additional efforts to identify male-specific dietary recommendations that optimize sperm quality and fertility are encouraged,” he said.
Further investigation could also elucidate details on potential confounding variables, commented Professor Allan Pacey from the Department of Oncology and Metabolism at the University of Sheffield in Sheffield, England. “[Despite the randomized design], it strikes me that if you were randomized to the nut-eating arm and were given nuts, you would know that. If this is the case, then the study was not ‘blind’, and there are many confounding factors that could have crept into the equation.”
“People also need to be aware that there is quite a big difference between improvements in semen quality measured by WHO* methods (or DNA damage) and improving the probability of pregnancy in the partners of men eating nuts. Surely, the latter is what we are most interested in,” Pacey added.