Dr. Steven Zeisel discusses the intersection of genetics and epigenetics in nutrition.
SNPs, Nutrition, and DNA Methylation
Well, we think that there are a number of genetic variants, single nucleotide polymorphisms. I’ll call them SNPs. These SNPs are extremely common in one carbon metabolism, especially among Caucasians. And we are reporting that these SNPs dramatically change whether you need choline or not, and that people who have these metabolic inefficiencies related to these snips are on the order of 25 to 85 times more likely to develop liver and muscle damage when deprived of choline.
And I think they’re also the people who are going to be more sensitive to making epigenetic modifications. Because they can’t either make choline, or they use it faster and they don’t have as much for methyl groups to do methylation with. One of these genetic variations turns out to be in a gene that makes choline from scratch in the liver. It’s called PEMT.
And that gene methylates phospholipid to form phosphatidylcholine and thereby choline. It turns out that gene is turned on in young women by estrogen. It’s there probably to get them through pregnancy where they have to deliver huge amounts of choline to build a good fetus.
And about half the population in North Carolina has a genetic variant, a SNP in that gene, that makes them unresponsive to estrogen. And so they reduce to the sad state of men and can’t make extra choline during pregnancy.
So that probably makes those women and their babies the most susceptible to variations in choline and methyl groups during pregnancy, and probably to some of these epigenetic phenomenon that we’re looking at in terms of brain development.