The study involved 189 college-age men from campuses in the Rochester, N.Y., area, whose diet and sperm were monitored.
The study, published in the journal Fertility and Sterility, found men who ate the most carrots, which are high in betacarotene had the best sperm motility, or its ability to swim toward an egg.
Betacarotene is a strongly colored red-orange pigment abundant in plants and fruits, with carotene turning the likes of carrots, pumpkins and sweet potatoes orange and lutein, a carotenoid or anti-oxidant also found in spinach, lettuce and egg yolks having an effect on sperm motility, the study said.
In addition, men with diets high in lycopene, the chemical that gives tomatoes their red color, had lower levels of abnormally shaped sperm. Lycopene is a bright red carotene, carotenoid pigment and phytochemical found in tomatoes and other red fruit and vegetables, such as red carrots, red bell peppers, watermelon and papayas, but not strawberries or cherries.
The researchers said, in a population of healthy young men, carotenoid intake was associated with higher sperm motility and, in the case of lycopene, better sperm morphology.