Folic acid. Polarised light micrograph of crystals of folic acid (folacin), a member of the vitamin B complex. Folic acid has been shown to reduce the risk of pregnant women giving birth to children with spine or brain defects. These defects (such as spina bifida) can occur in the embryo in the first stages of pregnancy; women of childbearing age and in early pregnancy are encouraged to include folic acid in their diets. Folic acid is a co-enzyme needed for forming body protein and haemoglobin. Dietary sources of folic acid include liver, leafy green vegetables, legumes like peas and beans, nuts, whole grains & brewer's yeast. Magnification: x40 at 6x7 cm size. Magnification: x75 at 4x5inch size.