We've known for a long time that women who do not get enough folic acid in their diets from the very first weeks of pregnancy are at increased risk of having children with birth defects of the brain and spine, including spina bifida.
Now, however, comes the surprising news that low folic acid levels in fathers can also increase the risk. This isn't actually new; the link has been known for a while. But it's been hard to understand how this could work.
Mothers provide the environment for the developing fetus, including not only the roof over its head, so to speak, but the complex bath of chemicals in which it swims during pregnancy. It makes sense that altering that chemical soup—with a deficiency of folic acid, for example—would have consequences for the fetus. But the father's only direct connection with the fetus is a single tiny sperm cell. How could his diet have anything to do with the fetus?
In a new study in the journal Nature Communications, researchers at McGill University in Montreal say they've found a possible explanation. Diet can't alter the DNA in the sperm, but it can alter something else, leaving a telltale signature that can disrupt proceedings weeks later in the womb.
A man's diet, it turns out, alters the epigenetics of his sperm. The genes in the sperm carry all the hereditary characteristics that we're familiar with—eye color, height, and so forth. But the proper operation of those genes requires that they be turned on or off appropriately. Epigenetic markings are small molecules that can attach to genes and control whether or not they are turned on.
The McGill researchers now suggest that the link between fathers' folic acid levels and their children's risk of birth defects might be a consequence of diet altering these epigenetic markings in his sperm.
Does this mean men contemplating having children should take folic acid supplements? There’s no way yet to know. Researchers must do more work to establish with certainty what is going on, and at this point they have no way of predicting how much folic acid is enough to reduce the risk—if, indeed, further studies prove that the risk is real.
Nevertheless, the study is yet one more examples of how important fathers are in the lives of their children--often in ways, such as this, that no one could have predicted. This one came out too late for inclusion in my book Do Fathers Matter? What Science is Telling Us About the Parent We’ve Overlooked, (due out for Fathers Day, 2014), but you will see many similar studies there, including a more complete explanation of epigenetics and its role in many aspects of children’s health.
This is perhaps one of the most exciting new areas of research regarding fathers, and I’m following it closely and will be blogging on it here in the weeks and months to come.