During the first week of pregnancy, the mice in all three groups were then administered injections of alcohol simulating a single binge drinking event in humans.
Following this alcohol exposure, Doppler ultrasound confirmed that 87 percent of the embryos of pregnant mice in the third group those not receiving folate supplementation beyond what was present in their normal diets had developed heart valve defects. The affected embryos were also smaller in size and their heart muscle walls appeared thinner.
Between days 15 and 16 of pregnancy in the mice equal to 56 days of gestation in humans -- ultrasound also showed that the high-folate diet protected heart valve development against lasting defects and restored heart function and embryonic size to near-normal levels. The moderate-folate diet provided only partial protection; in this group 58 percent of the mouse embryos developed heart valves that functioned abnormally, with a back flow of blood.
The researchers suggest that folate fortification may be most effective at preventing heart birth defects when administered at significantly higher levels than the doses currently recommended to prevent pregnancy complications -- both in normal women (0.4 milligrams recommended daily) and even in women who have delivered an infant with a spinal birth defect (4 milligrams daily). Although higher folate levels did not cause adverse side effects in the pregnant mice, Dr. Linask notes, the safety and effectiveness of higher doses must be proven with human trials.
The heart is the first organ to form and function during embryonic development of vertebrates. The USF researchers suggest that folate supplementation thwarts alcohol's damaging effect on an important early signaling pathway
|Contact: Anne DeLotto Baier|
University of South Florida Health