"This is a mouse model study, so it is not directly relevant to humans," study co-author Dr. David K. Martin, a researcher with the Children's Hospital Oakland Research Institute, tells HealthDay News.
"However, what this study does tell us is that it is possible that not just the diet but other environmental agents that a mother is exposed to could affect not only the heath of her child but also the health of her grandchildren.
"And this is the first study to nail down this kind of cross-generational effect on a specific gene," Martin says.
Martin and his team used a genetically identical strain of mice called Avy (viable yellow agouti) mice for the study. Because the mice are genetically identical, it is easier to isolate and compare genetic behavioral differences that could result from diet.
The scientists gave the mice a diet that humans would typically eat during their pregnancies. About midway through their terms, some of the mice were given dietary supplements including folate, choline, betaine, vitamin B12, zinc, and methionine. The mice received the supplements for only one week.
The scientists assessed the pups' fur color when they were born and found that the mice who had been exposed to the supplements in utero had dark brown coats. The pups of the mice who weren't given supplements generally had golden hair.
When the dark brown mice later became pregnant, they were not given any supplements. The researchers found that their children (the grandchildren of the mice who were given supplements) were still born with dark brown coats.
Martin and his colleagues say they don't yet know how many generations could be affected by the original mouse's diet - or what this means for humans.
"It's really not possible to do this kind of research with humans, because we can't do experimental manipulations of this kind among people," Martin says.
However, Martin does speculate: "This could go in humans for decades because the generation time in humans is about 30 years.
"So, 100 years from now - when a grandchild is 70 years old - society could still be dealing with the effects that stem from a mother who is pregnant now and is exposed to something that affects the fetus."
The findings are published in this week's issue of "Proceedings of the National Academy of Sciences."
