Two handfuls of walnuts could boost male fertility, researchers find

A cheap, easy addition to the daily diet of men has huge health benefits, and could even help couples suffering fertility issues.

Two handfuls of walnuts a day may be key to improving male fertility, according to a new study.

In a world-first, a Monash University team has found if men add the nuts to their diet it may help not only on their overall health, but also their sperm quality.

Nuts in the diet could be, suggests lead author Barbara Cardoso, a cheap and easily modifiable factor that could help couples experiencing fertility issues.

She says this is because raw or roasted nuts are high in healthy fats, dietary fibres, vitamins, minerals and polyphenols.

“These have known health benefits, but there has been few clinical studies to confirm the impact on fertility,” Dr Cardoso said.

So we looked at the literature and found there had only ever been two trials and they were both for men, none for women.”

She said eating nuts has been associated with a reduced risk of different types of chronic disease including type 2 diabetes, cognitive impairment and cardiovascular disease.

At least two servings of nuts daily as part of a Western-style diet in healthy men is shown to improve sperm parameters. Image: supplied.

“(But) little has been done on the impact on fertility. That is our goal, to do a study in Australia. In the meantime, provided you don’t have allergies, it doesn’t hurt to include any type of nut in your diet. They make you healthy.”

Dr Cardoso is from Monash University’s Department of Nutrition, Dietetics and Food and Monash Victorian Heart Institute.

She has been studying nuts for a decade and says the results of the team’s investigation published in the journal Advances in Nutrition on Monday are encouraging and warrant further studies into the “nut factor” on fertility.

The paper concludes nuts “seem to have a potential to promote successful reproductive outcomes”.

“Our meta-analysis shows that including at least two servings of nuts daily as part of a Western-style diet in healthy men improves sperm parameters, which are predictors of male fertility,” Dr Cardoso wrote.

“The implications of these findings are of great value to people trying to conceive, but we also need studies to assess the effects of nuts on female fertility.”

Dr Cardoso said they looked at the results of the two trials, which involved 223 healthy males aged 18-35, that showed sperm quality improved after three months of eating two handfuls of nuts.

Some ate whole-shelled English walnuts daily for 12 weeks, and the other group had mixed nuts containing walnuts, almonds and hazelnuts daily for 14 weeks. The control groups ate a similar diet with no nuts.

“Walnuts were common in both groups and are thought to help because they have omega-3 fat known to help with fertility.”

Dr Cardoso said while specific nuts were used and achieved similar results of improved sperm quality, she believes all nuts have the potential to help.

Study senior author Dr Nicole Kellow says many people think that nuts are fattening.

“But research shows that people who eat one or two handfuls each day are actually more likely to be leaner than those who don’t eat nuts,” she said.