Beijing -- Men who want their sperm to be healthy and swim faster need to eat more fruits and vegetables, according to a new research.

Researchers reported at a meeting of the American Society for Reproductive Medicine that the more produce a man consumed, the less sluggish his sperm.

"We think that sperm quality is affected by dietary antioxidant intake," said study author Dr. Vivian Lewis, a professor of obstetrics and gynecology at the University of Rochester in Rochester, N.Y.

Antioxidants in fruits and vegetables may help prevent damage to sperm that causes them to become sluggish and lose the ability to fertilize an egg, she said.

During the study, 48 infertile men and 10 fertile men who had fathered children in the last year completed questionnaires about their diets. Results revealed 83 percent of the infertile men had a low intake of fruits and veggies, defined as fewer than five servings a day, compared with 40 percent of the fertile men.

And overall, men who ate the fewest fruits and veggies had the lowest sperm motility.

In particular, the antioxidants glutathione and cryptoxanthin, which are prevalent in brightly colored produce such as leafy greens, tomatoes, peppers and oranges, were associated with strong, healthy sperm, Lewis said.

She recommended that men hoping to father children eat "a variety of fruits and vegetables, at least five servings a day."

Dr. Rebecca Sokol, a professor of obstetrics and gynecology at the University of Southern California in Los Angeles, who was not affiliated with the study, said it's a good idea for men who want to impregnate their partners to improve their diets. It could potentially help their sperm, and it certainly helps their overall health, she said.

Men also should avoid prolonged soaks in the hot tub and smoking cigarettes and marijuana, all of which may damage sperm, she said.

Another study presented at the conference linked cell phone use with impaired sperm, but the researchers and other experts said the study is too preliminary to advise hopeful dads-to-be to cut back on their talk time.

"You can only say there¡¯s a suggestion of an association," said Sokol. "You certainly can't conclude that it causes infertility."

In the study of 361 men undergoing evaluation for infertility, researchers found that the more time men spent on their cell phones each day, the unhealthier their sperm.

For instance, men who spent more than four hours a day on their cell phones had lower sperm counts, less motile sperm and more irregularly shaped sperm than men who didn't use cell phones. The differences ranged from about 30 to 50 percent.

Electromagnetic fields given off by cell phones could potentially impair sperm, said study author Ashok Agarwal, director of andrology at the Glickman Urological Institute at the Cleveland Clinic in Cleveland, Ohio.

But he noted that his team did not account for the use of laptop computers, PDAs and other devices that also have EMFs, and more studies are needed.

Joseph Farren, a spokesperson for CTIA-The Wireless Association, which represents the cell phone industry, disputed the findings.

"One study, as the researchers note, does not provide evidence of a reduction in sperm qualit," he said.