The study, published in Nature Communications, is the first to show that an environmental factor during the first few days of development can change DNA long term.
The researchers didn't look at how these genetic changes affect overall fetal development or the baby's health later in life. And they analyzed only six genes.
But there's growing from other studies that similar types of genetic changes may help determine a child's risk for some diseases, including diabetes, mental disorders and autism.
"Can diet affect other genes? What's the biological impact of those [DNA] modifications? At the moment we don't know the answer to those questions," says nutritionist , who contributed to the study. "But subsequent research we have — and haven't [yet] published — says it does matter."
Now we're not talking about altering the DNA code itself — you know, the building blocks of genes, the ? Rather, Prentice says the dietary effects he and his team have found seem to be changing whether genes are turned on or off in that earliest stage of embryonic development.
This on-and-off switch is controlled by decorating the DNA with a special tag, called . How much the six genes got tagged in the developing embryo depended on the levels of a few micronutrients in the mom's blood at the time of conception, Prentice and his team found.
The team examined several B vitamins and nutrients associated with them. They couldn't pinpoint exactly which ones were most important. But in general, when several of these nutrients, including vitamin B2, were at lower levels in mom's blood, the six genes had less methylation.
"The vitamin levels [in all the women] weren't way out of the normal range either," Prentice says. "If you took the blood to your doctor, he would say they were normal."
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