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.
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