Recent research suggests that women who eat high-fat foods during pregnancy may increase breast cancer risk in their daughters. A report just published goes further, concluding that what a women eats even before she becomes pregnant can cause changes in her DNA that are passed on to her offspring. The new study adds to a growing body of evidence about epigenetics: diet-induced changes in DNA that are passed down through generations.
Epigenetics: modification, not mutation
A poor diet could put your children at an unhealthy disadvantage throughout their lives because of epigenetics. Epigenetics is the term for changes in gene expression from environmental forces. Rather than a mutation, the genetic modifications are the result of a process called DNA methylation. While the structure of the DNA remains unchanged, methylation represses gene expression, or switches off certain genes.
The effects of epigenetics on a subsequent generation may have first been observed in children born to mothers during a famine in The Netherlands at the end of World War II, who were susceptible to diseases later in life such as glucose intolerance and cardiovascular disease.
Inheriting metabolic syndrome
Scientists suspect that epigenetics is behind the increased risk for diseases such as obesity and diabetes in children today compared to their parents. Researchers at the University of Groningen in the Netherlands found that mice overfed to develop metabolic syndrome—a deadly combination of insulin resistance, glucose intolerance and obesity—passed susceptibility for the condition to their offspring. The subsequent generation of mice developed metabolic syndrome without overeating.
Hereditary breast cancer risk
The Dutch researchers said the diet of human adults induces changes in offspring the same way. Researchers from Virginia Tech and Georgetown University claim women who eat high-fat foods during pregnancy may increase the risk of breast cancer risk in their daughters, granddaughters and great-granddaughters.
In their study, they compared rats fed either a high-fat diet or a high-estrogen diet to rates on a normal diet. They found that mice on a high-fat diet passed the increased breast cancer risk through both the male and female. The offspring of rats on the high-estrogen diet had up to a 50 percent higher risk of breast cancer, passed through the female.
Epigenetics before pregnancy
Other research on mice from the University of North Carolina at Chapel Hill suggests that diet before pregnancy can also influence epigenetics. Scientists there found that a diet supplemented with alpha-linolenic acid (an omega-3 fatty acid) in the form of flaxseed oil increased methylation of a gene known as Fads2, which regulates the metabolism of polyunsaturated fatty acids.
The female mice were then bred with males on a control diet. The expression of the Fads2 gene was suppressed in the offspring, which inherited the DNA change from their mothers. Their ability to metabolize essential fatty acids was dramatically affected by the mother’s diet before pregnancy.
Epigenetic research suggests that we are what we eat … and so are our children. In addition to socialization, education and economical influence, our diets have a long-lasting effect on the outcome of their lives. This knowledge comes with a responsibility to lead a healthy lifestyle, because future generations depend on it.