March 28, 2003 -- For women with diabetes, eating high-antioxidant foods like spinach, swiss chard, and wheat germ may prevent serious birth defects in their unborn babies. Serious birth defects like neural tube defects lead to devastating neurological consequences, and in women with diabetes, they can occur two to five times more often than in women without diabetes.
"Neural tube [birth] defects occur very early in pregnancy, about the time a woman may realize that she is pregnant," says researcher Mary Loeken, PhD, professor of physiology at Harvard Medical School, in a news release. Her study appears in the April issue of the journal Diabetologia.
For more than 10 years, Loeken has studied how a mother's diabetes during pregnancy affects genes in the embryo. Recently, her studies have focused on pregnant female mice that were bred to have diabetes. She has also focused on a specific gene -- the Pax-3 gene -- and its effects on the embryo's development. She found that mice embryos of mothers with diabetes have low levels of this gene and three times more neural tube defects.
Mothers with diabetes have abnormally high blood sugar levels, which means their embryos also have high blood sugar levels, she explains. This excess blood sugar produces more damaging free radicals in the blood faster than antioxidants can eliminate them in the underdeveloped embryo -- what's known as oxidative stress. This stress can lead to inhibition of the Pax-3 gene, and this may explain the genetic basis for neural tube defects that occur in diabetic pregnancies. Even mild oxidative stress can cause birth defects, Loeken says.
Antioxidant supplements may be just as important as folic acid for all women of childbearing age, says Loekin. Her finding may explain why folic acid -- also an antioxidant -- plays such a key role in preventing birth defects. And it may explain some birth defects that occur even in women who don't have diabetes, in whom oxidative stress can be caused by other means.