Folic acid is the synthetic form of vitamin folate. Because of its high stability and bioavailability, it is the form of folate added to bread in Canada to reduce birth defects. There are health concerns about long-term folic acid consumption. Another form of folate, L-5-methyltetrahydrofolic acid (L-5-MTHF) has become available which does not have these health concerns. Unfortunately L-5-MTHF is not as stable as folic acid, but the investigators have developed a method to stabilize L-5-MTHF in food. The investigators plan to conduct a randomized trial to compare the bioavailability of bread fortified with L-5-MTHF versus folic acid.