Eating nuts improves sperm quality, study suggests

Eating nuts may boost sperm quality, research suggests.

It is increasingly coming to light that certain lifestyle habits, like smoking and excessive alcohol intake, can affect a man’s fertility.

To better understand the impact of diet, scientists from Universitat Rovira i Virgili in Spain analysed the effects of adding 60g (2.1oz) of almonds, hazelnuts and walnuts a day to a typical Western diet.

After 14 weeks, results revealed the men who ate the nuts experienced enhanced sperm methylation. This occurs when so-called methyl groups are added to a DNA molecule, changing its activity but not the genetic sequence.

Although unclear, this could stop certain tumour-causing genes from expressing themselves and being passed on to future offspring.

The scientists did not specifically investigate whether these men were more likely to father children than those who abstained from nuts. They added, however, the results suggest sperm respond to a man’s diet, which may affect his “ability to fertilise”.

“This work demonstrates 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 co-lead author Albert Salas-Huetos, who now works at Harvard University.

Epigenome refers to all the chemicals changes that occur to DNA and could be passed down to an individual’s children.

The scientists analysed 72 healthy, non-smoking men who took part in the FERTINUTS trial.

Forty-eight of the men added 60g of tree nuts – like almonds, hazelnuts and walnuts – a day to their diet, while the remaining 24 continued to eat as normal for 14 weeks, avoiding any nuts.

Results – published in the journal Andrology – revealed the men who ate the nuts experienced methylation to 36 genomic regions of their sperm.

Of these regions, 97.2% displayed hypermethylation – when more methylation occurs than what is considered a normal amount.

“Adding nuts to a regular Western‐style diet subtly impacts sperm DNA methylation in specific regions, demonstrating that there are some sperm epigenome regions that could respond to diet,” concluded the scientists.

The NHS already recommends men boost their chances of fathering a child by eating a healthy, balanced diet that includes at least five portions of fruit and vegetables a day.

Although unclear exactly how nuts may affect sperm, the heart-healthy snack contains unsaturated fatty acids and other nutrients that may lower “bad” cholesterol, helping to prevent the build-up of plaque in the arteries.

Other nutrients like omega-3, fibre and vitamin E may also reduce inflammation and the onset of clots, while protecting the lining of the heart.