It was also improved among those who took brisk walks, compared with those who either did little physical activity or went running.
The three papers, presented this week at the annual meeting of the American Society of Reproductive Medicine in Florida, highlight the importance of the lifestyle of a prospective father as well as that of their female partner in determining whether or not they can have a baby.
In the first study, researchers at the Harvard School of Public Health looked at what 188 students ate and drank.
They divided their diets into a "prudent" one characterized by high intake of fish, fruit, vegetables and pulses, and a "western" one full of pizza, red and processed meat, high energy drinks and snacks.
Those with the best diet had 11% more motile sperm -- better at swimming towards an egg -- than those with the least healthy eating habits.
Lead researcher Audrey Gaskins said, "Motility is most important for couples who want to try to conceive naturally. A small increase could lead to a small increase in fertility."
A separate study at Harvard analyzed the diet of 99 men who were already attending a fertility clinic because they and their wives or girlfriends were unable to get pregnant.
Academics found that consumption of Trans Fatty Acids -- previously found in many fried fast food joints but now being phased out -- was linked to sperm concentration.
Men who took 1.3% of their calories from trans-fats had on average 48 million sperm per milliliter of semen, compared with 79 million among those who had consumed just 0.7% of their calories in the form of the fat.
Dr. Allan Pacey, a fertility expert at the University of Sheffield, commented, "The influence of a man's diet on his semen quality has been of interest for some time.
"For example, there is now good evidence from a variety of studies that men with a higher antioxidant intake have slightly better semen quality and are more likely to become fathers than men who don't. Similarly, there are also studies showing that men who consume key nutrients, ejaculate better sperm.
"Therefore, the results of this study, comparing a Western diet with one which is more 'Mediterranean,' is not really a surprise and nicely illustrates that a good diet is of benefit when trying to conceive."
From the October 19, 2011, Prepared Foods' Daily News.