Diet and risk of birth defects

Women who eat lots of foods that tend to raise blood sugar may be more likely to have a baby with birth defects of the brain or spine. These foods, known as high glycaemic index foods, include white bread and other highly processed grains, potatoes and soft drinks. Neural tube defects such as spina bifida arise in the first several weeks of pregnancy, when the brain and spine are beginning to take shape. One nutritional factor in this early period - a woman's intake of the B vitamin - folic acid, is known to decrease the risk of these birth defects. There is also evidence that a mother's obesity or diabetes might raise the risk of neural tube defects, suggesting a role for maternal blood sugar levels.According to the researchers at the California Birth Defects Monitoring Programme in Berkeley, USA, among more than 900 California women in the study, those who ate more foods with a high glycaemic index around the time of conception had a higher risk of having a baby with a neural tube defect. The link was strongest for obese women; those who ate the most high glycaemic index foods had four times the risk of having an affected baby as obese women who ate the fewest.The glycemic index measures how strongly and quickly blood sugar rises after a person eats carbohydrate-containing food. The sugars in foods with a high glycaemic index are quickly digested and absorbed, creating a surge in blood sugar levels. In contrast, the carbohydrates in foods like fibre-rich whole grains, beans, fruits, vegetables, and some dairy products typically cause a slower release of sugar into the blood.The new findings support evidence suggesting that problems in blood-sugar control may contribute to the development of the birth defects. But researchers still do not fully understand the roots of neural tube defects. Eating a well balanced diet with enough folic acid remains the best advice for cutting the risk of neural tube defects. Foods rich in the vitamin include fortified grains and breakfast cereals, leafy greens like spinach, and orange juice.