Eating just 2.5 ounces of walnuts per day can improve your testicles ability to produce quality sperm. Walnuts contain high quantities omega-3 fatty acids which some studies have linked to improved sperm quality.
This study appeared in the journal Biology of Reproduction in August 2012. I might also add that the California Walnut Commission sponsored the study.
Bottom Line: For men with abnormal or low sperm counts and are trying to achieve a pregnancy, consider a handful of walnuts every day. It may not help but it certainly won’t hurt.