Men who add nuts to diet can ‘significantly improve sperm quality’

Men who add a handful of nuts to their diet can increase their sperm quality and fertility, a new study shows.

Spanish researchers compared men who were fed a mixture of tree nuts – almonds, hazelnuts and walnuts – over 14 weeks as a supplement to their standard Western diet with those who weren’t. 

The inclusion of this nut mix for 14 weeks significantly improved the sperm count, viability, motility (its ability to move independently) and morphology (length of the head and tail), they found. 

Nuts contain omega-3 fatty acids, antioxidants and the B vitamin folate, which has been linked with fewer sperm abnormalities. 

The study is an indicator that adding nuts to a basic British diet can modulate male fertility and has an effect on sperm’s ‘epigenetics’ – changes in gene expression.

A handful of almonds, hazelnuts and walnuts (pictured) every day boosts men’s sperm production and morphology

The study was led by researchers from the Human Nutrition Unit of the Universitat Rovira i Virgili in Tarragona, Spain. 

‘This work demonstrates that there are some sensitive regions of the sperm epigenome that respond to diet, and which can result in changes in sperm and in its ability to fertilise,’ said study author Albert Salas-Huetos, who is now based at Harvard University in the US. 


Epigenetics is a field of molecular science which involves altering the expression of certain genes. 

It is defined as: ‘The study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself.’

Instead of changing the genes present in a living thing, it changes which of its genes are ‘turned on’.

Environmental and lifestyle factors have been blamed for the decline of sperm quality, including diet and smoking. 

Prior studies have reported a close association between the alteration of specific sperm signatures and semen quality.

For their study, Salas-Huetos and colleagues analysed DNA methylation, an epigenetic marker that tells genes to switch on or off.  

DNA methylation adds a methyl group – CH3, a carbon atom with three bonded hydrogen atoms – to a specific region of DNA. 

The presence of this molecular group then alters a gene’s expression and can turn off harmful genes, such as those associated with cancer. 

‘This is very important in the fertility process because spermatogenesis (the process by which the sperm cells are created) and embryogenesis (the process by which the embryo is created) are very regulated processes that need precise control of the gene expression,’ Salas-Huetos told MailOnline. 

This study was conducted with 72 healthy young male participants, all of whom were non-smokers.

Most of the participants – 48 in all – were assigned to the ‘nut’ group, while the remaining 24 participants were assigned to the control group and didn’t get a nut supplement. 

The 48 men in the nut group consumed 60 grams per day of mixed nuts – including almonds, hazelnuts and walnuts – without making any other changes to their diets. 

The researchers observed that, after the 14 weeks, the methylation of 36 genomic regions was significantly different only in the group that consumed nuts. 

In all, 97.2 per cent of these regions, or 35 out of 36, displayed an increase of methylation, they found.    

The research suggests guys don't really have to change their diet other than adding a handful of nuts if they want to make their sperm healthy

The research suggests guys don’t really have to change their diet other than adding a handful of nuts if they want to make their sperm healthy

According to the researchers, these findings provide the first evidence that adding nuts to a regular Western-style diet impacts sperm DNA methylation in specific regions.

Researchers also point out that the potential health benefits of the study, which has been published in Andrology, require further study to verify the results found in other populations.  

Sperm counts have halved in the western world over the past four decades, which, alongside rising testicular tumours, could be behind plummeting fertility rates and a dependency on IVF, according to Professor Niels Skakkebaek from the University of Copenhagen, who was not involved with the study. 

Hormone-disrupting pesticides sprayed onto everyday food may be to blame as the changes are occurring too rapidly for genetics to be at fault.

‘Alterations in our genome cannot explain the observations as changes have occurred over just a couple of generations, Professor Skakkebaek said. 

‘Modern lifestyles are associated with increased exposure to various endocrine-disrupting chemicals such as pesticides that may be harmful to humans even though exposure to individual chemicals is low.’  

A study published in 2015 revealed that men who ate the highest amount of fruit and vegetables with high levels of pesticides had a 49 per cent lower sperm count than men who consumed the least amount. 


Walnuts have several brain-boosting properties and are high in Omega-3 fatty acids. They're also high in anti-oxidants which help with inflammation and can protect cells

Walnuts have several brain-boosting properties and are high in Omega-3 fatty acids. They’re also high in anti-oxidants which help with inflammation and can protect cells

A handful of walnuts a day may prevent heart disease and bowel cancer, research suggested in May 2018.

Eating just a third of a cup of walnuts for six weeks significantly reduces the production of excess bile acids, as well as lowering ‘bad’ cholesterol levels, a study found.

Previous research has linked such bile acids to bowel cancer, while lower cholesterol levels are associated with a reduced risk of heart disease.

Researchers believe walnuts’ high-fibre content encourages the growth of ‘good’ bacteria in the gut, which benefits people’s heart and colon health.

The scientists also found that despite walnuts being relatively high in calories, with around 28 per nut, only 80 per cent of them are absorbed, with gut bacteria using up the remaining 20 per cent.

Results further suggest people who eat a handful of walnuts a day produce less secondary bile acids, which are made in the bowel rather than the liver like their primary counterparts.

Lead author Professor Hannah Holscher, from the University of Illinois, said: ‘Secondary bile acids have been shown to be higher in individuals with higher rates of colorectal cancer.

‘Secondary bile acids can be damaging to cells within the GI tract and microbes make those secondary bile acids.

‘If we can reduce secondary bile acids in the gut, it may also help with human health.’


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