Epidemiological studies suggest that paternal diet, prior to conception, can influence the health of offspring.
One suggested method for paternal transmission of environmental information is via the sperm epigenome. The epigenome includes heritable information such as DNA methylation.
A study conducted by McGill University in Montreal, looked at effects of paternal diet in mice, as mice are genetically similar to humans. The researchers hypothesised that dietary supply of methyl donors would alter epigenetic reprogramming in sperm.
Female mice were fed a healthy pellet diet, with sufficient levels of folate. They were mated with 35 male mice who were fed the same folate sufficient diet as well as with 32 male mice who ate pellets that were low in folate, designed to mimic low levels of folate in the human diet.
Results demonstrated that the fertility of the folate deficient male mice was compromised, with a low pregnancy rate of 52.38%, compared to a rate of 85% in the folate sufficient males.
Of the offspring sired by the folate deficient males, 27% had visible gross anatomical abnormalities including muscle and skeletal defects, face and skull abnormalities, small lower jaws and webbed or fused digits. Only 3% of the folate sufficient sired offspring had abnormalities and all were minor including a runt and skin discolouration.
The sperm of the folate deficient mice was analysed and found that epigenetic markers were altered for genes linked to development and diseases such as diabetes and cancer.
Further to this, researchers also detected changes in epigenetic markers in the placenta in pregnancies sired by the folate deficient males. Whilst placenta weight and size did not differ, there were two incidents of fused placentas which seemed to compromise embryonic development in both cases.
These results contribute further support to the theory that epigenetic markers in spermatogenesis are adept and adjustable and can be potentially altered by nutritional, hormonal and toxin exposure. Investigations like this demonstrate that male preconception nutritional status and overall health may be as important as females’, and that sperm epigenome plays a key role in embryonic development.
- Lambrot R, Xu C, Saint-Phar S, et al. Low paternal dietary folate alters the mouse sperm epigenome and is associated with negative pregnancy outcomes. Nat Commun 2013;4:2889. [Full text]