"They were almost exactly like the poorly raised group," says Szyf, who announced his findings at a small meeting on environmental epigenomics earlier this month in Durham, North Carolina. Though the experiment impaired well-adjusted animals, the opposite should be possible, and Szyf has already shown that a chemical called TSA that is designed to strip away methyl groups can turn a badly raised rat into a more normal one.
No one is envisaging injecting supplements into people's brains, but Szyf says his study shows how important subtle nutrients and supplements can be. "Food has a dramatic effect," he says. "But it can go both ways," he cautions. Methionine, for instance, the supplement he used to make healthy rats stressed, is widely available in capsule form online or in health-food stores and the molecules are small enough to get into the brain via the bloodstream.
Rob Waterland from Baylor College of Medicine in Houston, Texas, who attended the meeting, says Szyf's ideas are creating a buzz, as they suggest that methylation can influence our DNA well into adulthood. "A huge number of diseases are caused by changes to how our DNA is expressed, and this opens up new ways of thinking about how to prevent and treat them," he says.
But Waterland points out there is still much work to be done. Substances like methionine and TSA are, he says, a "sledgehammer approach," in that they are likely to demethylate lots of genes, and we don't even know which they will affect. But he speculates that techniques such as "RNA-directed DNA methylation," so far tested only in plants but theoretically possible in mammals, may allow us to target such methylation much more precisely.