The results were consistent with sperm improvement observed in other studies that looked at diets rich in omega-3, antioxidants such as vitamin C and E, selenium and zinc, and folate.
Fertility specialists in Spain examined the sperm of 119 healthy young men before and after a 14-week study during which half were randomly assigned to have 60g of mixed nuts added to their diet each day.
The findings of the study were presented at a meeting of the European Society of Human Reproduction and Embryology (ESHRE 2018) in Barcelona.
The trial involved measuring conventional semen parameters and molecular changes over a 14-week period.
Although these are statistically significant results from a randomised trail with a high level of scientific evidence, Salas-Huetos emphasised that subjects in the study were all healthy and apparently fertile men following a western-style diet.
A study has found that eating nuts each day can provide a big boost to men hoping to become fathers in the future. And about 40-50% of infertility cases are related to problems in men.
The investigators conclude from the study that there is a "beneficial role for chronic nut consumption in sperm quality" and nuts should be a part of male dietary recommendations.
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They found a 16 percent increase in sperm count from those who had the nuts.
"Therefore, with regard to this study, I am not surprised that a diet rich in nuts is associated with better sperm".
The results of this new study confirm previous research carried out in 2013 by the researchers from the Fielding School of Public Health at UCLA University in California, USA, which also revealed that a considerable quantity of nuts, consumed daily, would improve the sperm quality and male fertility, in general.
"These four parameters are all associated with male fertility".
Dr Salas-Huetos said he couldn't advise nut supplements for men attempting to conceive "based exclusively on the results of this study". For the analysis, the researchers recorded not only the quality of the sperm but also the changes that occurred in several molecular factors, including sperm DNA fragmentation. "We can't yet say that", said Salas-Huetos, "based exclusively on the results of this study".
Any nut would be useful in the prevention of male infertility. The work, funded by the International Nut and Dried Food Council, has been accepted for publication in the American Journal of Clinical Nutrition.