Herein lies the uncertainty of nutrition's epigenetic effects on cells, said Jirtle. Folic acid is a staple of prenatal vitamins, used to prevent neural tube defects like spina bifida. Yet excess folic acid could methylate a gene and silence its expression in a detrimental manner, as well. The data simply don't exist to show each nutrient's cellular effects.

Moreover, methylating a single gene can have multiple effects. For example, the Agouti gene regulates more than just coat color. Mice that over-express the Agouti protein tend to be obese and susceptible to diabetes because the protein also binds with a receptor in the hypothalamus and interferes with the signal to stop eating. Methylating the Agouti gene in mice, therefore, also reduces their susceptibility to obesity, diabetes and cancer.

Hence, the researchers stress the importance of understanding the molecular effects of nutrition on cells, not just the outward manifestations of it.

"Diet, nutritional supplements and other seemingly innocuous compounds can alter the development in utero to such an extent that it changes the offspring's characteristics for life, and potentially that of future generations," said Waterland. "Nutritional epigenetics could, for example, explain the differences between genetically identical twins, or the disparities in the incidence of stroke between the South and the North. The possibilities are endless."

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Contact: Becky Levine
levin005@mc.duke.edu
919-684-4148
Duke University Medical Center
1-Aug-2003