It may be possible that the form of folic acid present in foods is more potent in preventing birth defects. Supplementation of iron and folic acid is necessary during pregnancy for the creation of extra red blood cells. Prenatal vitamins can help a healthy diet, but they are not a substitute for a healthy diet. That goes for the rest of us too. Pregnant or not.
Balance is the operative word here.
Balanced eating is the key to not only a long life, but a high quality life as well. Let this be your key to becoming empowered the good life and not a fallen victim to it. Whenever possible, eat raw fruits and vegetables. Vitamin C is very easily oxidized by air. In fact, orange juice and cantaloupe can lose half their Vitamin C content if not stored properly.