In a new study, eating nuts daily has been linked to improved measures of fertility in men, including sperm quality and reproductive cell function.
Led by scientists in Spain from Universitat Rovira i Virgil in Reus and the Autonomous University of Barcelona, the findings of the study were presented on Wednesday at the annual meeting of the European Society of Human Reproduction and Embryology in Barcelona. Their work was funded by the International Nut and Dried Food Council, and is set to be published in the American Journal of Clinical Nutrition, according to The Guardian.
Infertility is a growing problem. Dr Albert Salas-Huetos, one of the study’s authors from the Human Nutrition Unit of Rovira i Virgil, pointed out that the quantity and quality of human sperm has been declining significantly over the past 40 years, a change he attributed to “pollution, smoking, and trends toward a western-style diet.”
One in seven couples experience difficulty getting pregnant, according to BBC News, with nearly half of infertility cases attributable to men.
119 men ranging in age from 18 to 35 participated in the 14-week, randomised clinical trial. The men were divided into two groups: one added 60 grams of mixed nuts, including almonds, hazelnuts and walnuts, per day to their usual diet, while the other group consumed their usual diet without any added nuts.
Researchers analysed sperm and blood samples at the beginning of the experiment and after 14 weeks. They found that men who added nuts to their diet experienced a 16% increase in their sperm count, on average.
Slight improvements in sperm vitality, movement, shape and size were also observed in the nut group, characteristics that the World Health Organisation (WHO) lists as indicators of sperm quality and male fertility.
The results are consistent with other recent studies showing diets rich in omega-3 fatty acids, antioxidants and a B vitamin called folate – nutrients contained in nuts – can improve fertility in men.
“The results of our study could potentially help couples’ chances of conceiving,” Salas-Huetos told The Guardian.
However, Salas-Huetos noted that it is too early to tell men seeking to conceive to add nuts to their diet based on the results of the study alone. “But evidence is accumulating in the literature that healthy lifestyle changes such as following a healthy dietary pattern might help conception – and of course, nuts are a key component of a Mediterranean healthy diet,” he added.
Other experts welcomed the study, but said the results should be interpreted cautiously for now.
“The fact that the study has taken place is good,” Virginia Bolton, a consultant embryologist at Guy’s and St Thomas’s hospital in London, told The Guardian. “But we need to see this translated into an effect on fertility.”