The recommended daily dose of folic acid for those who are trying to get pregnant is 400 to 800 mg. Nursing mothers should take 500 mg of folic acid. Taking a supplement is easy and allows you to be certain you met their recommended daily intake. There are quite a few foods that contain folate, but they are not a natural part of many peoples' diets.
It is logical to assume that folate is easier to absorb than the synthetic version. That is certainly true for iron supplements, for instance. In this case, though, evidence suggests that folic acid is actually more easily used by the body than folate. Although it may be possible to get all your folate from food sources, the supplement may actually be doing you more good.
On top of that, it would be very rare for someone to eat all the right foods containing folate and still meet all their other nutritional needs as well. Apply caution. This doesn't apply to cereals, breads, and rice that are fortified with folic acid and that can often fulfill your daily requirement. In such cases, these products will be labeled as folic-acid enriched on the nutritional information label.