The latest issue of the journal the Biology of Reproduction says that eating two handfuls of walnuts a day may improve sperm health in young men.
In the study, 117 healthy men between the ages of 21 and 35 had their sperm tested for shape, movement, and vitality. Half of the men added 75 grams of walnuts to their diets for 12 weeks. The other half were asked not to change their diets with the exception of avoiding tree nuts. According to the lead author, Professor Wendie Robbins from UCLA’s Fielding School of Public Health, “We found a significant improvement in sperm parameters in the group that consumed the walnuts. The men who ate no tree nuts saw no change.” The parameters that showed improvement were: sperm concentration, vitality, movement, shape and the presence of chromosome abnormalities.
The results may hold promise for the study of infertility, as the 20% of men in the study who were found to have low sperm counts after the initial testing also had the biggest improvement in sperm quality at the end of the study.
The fatty acids found in walnuts are thought to help with sperm development, though it is not yet known whether this will also improve fertility. Co-author Catherine Carpenter, from the UCLA Centre for Human Nutrition said: “Walnuts provide a particularly rich source of a-linolenic acid, a natural plant source of omega-3, which we suspect may have been responsible for the improvements we observed.” A follow-up study would look at whether walnuts improve conception rates in sub-fertile men.
“Women are not the only ones who should be paying attention to what they eat when they are trying to get pregnant,” she added. “This study shows that what men eat is important too.”
The study was funded in part by the california Walnut Commission.