Men struggling to have children could boost their fertility by eating walnuts, a new study claims.
Scientists say that eating a walnut-enriched diet may improve sperm quality.
Research found that the nut reduces lipid peroxidation, a process that can damage sperm cells.
This form of cell damage harms sperm membranes, which are primarily made up of polyunsaturated fatty acids.
Walnuts are the only tree nut that are predominantly comprised of these fatty acids – meaning they are uniquely powerful for replenishing sperm cells.
Just one ounce of walnuts contains 13 grams of polyunsaturated fatty acids (PUFAs), out of 18 grams of total fat.
The study, conducted at the University of Delaware, gave two groups of mice either a walnut-enriched diet or a control diet for nine to 11 weeks.
One group was made up of healthy male mice and the other was male mice that were genetically predetermined to be infertile.
Researchers found significant improvements in sperm motility and morphology in mice who were consuming 20 percent of their daily calories from walnuts – equivalent to 2.5 ounces a day for humans.
Even the infertile mice saw an improvement in sperm morphology and both groups experienced a notable reduction in peroxidative damage.
Sperm motility (movement) and morphology (form) are markers of semen quality, which is a predictor of male fertility.
‘What’s fascinating is we found that eating walnuts can actually help improve sperm quality, likely by reducing peroxidative damage in sperm cells,’ said lead researcher Dr Patricia Martin-DeLeon of the University of Delaware.
‘More research is needed to understand the specific nutrients in walnuts that may contribute to this improvement, but the findings suggest that walnuts may be beneficial for sperm health.’
The study piggybacks off a previous randomized control trial that showed eating 2.5 ounces of walnuts per day – about 30 walnuts halves – improved sperm vitality, motility and morphology in men.
Over 100 healthy young men consumed their usual Western-style diet throughout the study and participated in monthly calls to share their dietary intake with the researchers.
This research established the potential role of walnuts in male fertility.
‘This animal research sheds light on how walnuts may improve sperm quality and is a great follow up to our human study that showed what effect walnuts may have,’ said Dr Wendie Robbins, of the UCLA Fielding School of Public Health and School of Nursing, who led the first trial.
‘Studies that look at the factors underlying sperm quality improvements are very valuable for advancing research on this important topic.’
The researchers hope to conduct larger and longer-term studies, as well as studies in more diverse male populations, to confirm the mechanism that makes walnuts improve sperm quality.
A couple is said to be infertile if there is no pregnancy after one year of normal sexual activity without contraceptives.
In approximately 40 percent of infertile couples, the male partner is either the sole cause or a contributing cause of infertility.
There are many causes of male infertility including a low sperm count, sperm that don’t move quickly enough (they die before they reach the egg) and sperm that are not formed correctly.
The majority of fertility treatments, however, have been geared towards women in the form of fertility drugs to stimulate ovulation or surgery to fix problems such as an abnormal uterine shape or blocked Fallopian tubes.
For men, such treatments that currently exist include a few fertility drugs and surgery in the form of varicocele repair, ejaculatory duct resection and vasectomy reversal.