Attention sperm: Bacon bad, fish good
The quality of a man's semen is directly related to his ability to help conceive a child. But science hasn't found many solutions for men looking for a baby-making boost. Now a study suggests men who are hoping to start families may want to pay attention to what they eat.
A study presented at the American Society for Reproductive Medicine in Boston this week, and published in the journal Fertility and Sterility, suggests that processed meat intake is linked to poorer semen quality, and fish is linked to better semen quality.
Myriam Afeiche, research fellow at the Harvard School of Public Health, and her colleagues looked at how types of meat could be associated with semen quality. They took samples from 156 men at the Massachusetts General Hospital Fertility Center in Boston and had the men answer a questionnaire about their eating habits.
What does semen have to look like to be considered high-quality? The researchers considered four main parameters:
The concentration of sperm is one part of it. So is motility, or how fast the sperm move. The shape of the sperm also matters, as does the total sperm count -- that's the concentration multiplied by volume.
The researchers did not look at individual kinds of processed meat, so this study won't tell you if bacon could be more sperm-stunting than hamburgers, or vice versa. But higher intake of processed meat appeared to be related to a lower percent of "morphologically normal" -- or well-shaped -- sperm.
Regarding fish, it seemed that men who ate more dark meat fish -- such as salmon, bluefish and tuna -- had higher total sperm count; more white meat fish -- such as cod and halibut -- was associated with normally-shaped sperm.
The researchers only looked at associations, not causes. It is unclear whether processed meat actually causes changes in sperm, or if it does, how that would happen. It's possible men who eat more processed meat have an unhealthier diet overall, which could affect their semen. Same goes for fish intake and sperm; researchers don't know what about fish may benefit the littler swimmers.
"There might be something else going on, but we’re not sure what it is," Afeiche said.
Afeiche and her colleagues found that neither total fat intake, including saturated fat, nor animal fat could explain these connections.
"We have previously found in this same study population that saturated fat was related to lower total sperm count and sperm concentration," she said.
A 2012 study in the American Journal for Nutrition found that, in a sample of 701 Danish men, high intake of saturated fat was associated with low sperm concentration and low total sperm count.
Afeiche's findings seem "quite related to our study," said Tina Kold Jensen, professor of environmental health at University of Southern Denmark, who led the saturated fat study. But Jensen did not have any answers either about what the saturated fat would be doing biologically to diminish sperm quality.
If modifying his diet can help a man boost his semen quality, that would be an easy intervention for many couples who are having trouble conceiving.
But it should also be noted that there's not a linear relationship between semen quality and likelihood of conception, says Afeiche. The two are related, of course, but all it takes is one sperm to conceive.
Afeiche isn't ready to make any dietary recommendations based on her new research. This is only one study, she said, and it was done on a relatively small group of men in Boston.
"I would say that further studies are needed to confirm this," she said.
Researchers will have to recruit a larger group of men from a wider geographic area to make the findings applicable to semen everywhere.