Two handfuls of walnuts. That's all it takes. Just two handfuls (around 75 grams/day), and your sperm quality will improve "in terms of concentration, vitality, movement, shape and chromosome abnormalities," according to a study recounted in the latest issue of the journal Biology of Reproduction.
Who here even knew that sperm shape was a thing? (Fun fact: according to the Mayo Clinic, only four percent of the swimmers in your average semen sample are considered "morphologically normal" — that's a lot of wonky spermatozoa.)
The researchers behind the study say there's still no word on whether livelier, shapelier, and higher concentrations of sperm actually boost a man's fertility, but according to the BBC, followup studies are in the works:
The fatty acids found in these nuts are thought to have helped sperm development.
Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield said: "It would be relatively easy to poke fun at studies like this, but there is increasing evidence to show that aspects of a man's diet can affect the number and quality of sperm produced by his testicles."
The researchers say the next step is to work with couples who are attending infertility clinics to determine if placing sub-fertile men, with poor semen quality, on a walnut diet results in better success conceiving.
The study has its shortcomings. As Pacey points out, "the men in the walnut-eating arm of the trial could have altered other aspects of their behavior to give the results shown in the paper," so the study could be improved by producing tablets out of walnut extract and making the study completely blind.
That being said, the researchers are confident in their results. "the results of the study show a small but statistically significant improvement in sperm health," says Pacey.
And sperm-boosting or not, why not just enjoy some walnuts? They're delicious. You don't need a peer-reviewed study to tell you that, amirite?
Read the study in full (no subscription required) in the latest issue of Biology of Reproduction.