Eating nuts may enhance male fertility, a Monash University-led research review has found.
The authors now want more research into the potential benefits of nuts for male and female fertility after finding only two intervention studies on men eating more than two serves per day and none on women.
Published in Advances in Nutrition, the first systematic review of evidence on the association between nuts and fertility in men and women found daily intake could improve sperm quality.
It found four papers, including two randomised clinical trials that gave healthy men on a western style diet at least 60 grams (two handfuls) of nuts per day. Meta-analysis of the trials, which involved a total of 223 healthy males aged 18-35, found sperm quality but not sperm concentration improved.
One trial provided 75 grams of whole-shelled English walnuts per day for 12 weeks, and the other provided 30 grams of walnuts, 15 grams of almonds and 15 grams of hazelnuts each day for 14 weeks. A control group ate a similar diet with no nuts.
First author Dr Barbara Cardoso, from Monash University's Department of Nutrition, Dietetics and Food and Monash Victorian Heart Institute, said the trials allowed for the possibility that those eating nuts were healthier anyway.
Dr Cardoso also said while specific nuts were used, other combinations would probably also help - as long as those eating them had no allergy issues.
"The statistical analysis in both studies was adjusted for other factors such as physical activity," she said. "The findings show that this simple strategy has positive effects regardless of other lifestyles.
