Folic acid, a form of the vitamin folate, is added to grain products in Canada to help reduce
birth defects. Folic acid is the synthetic form of folate and is very stable (doesn't break
down) when added to foods. There are emerging health concerns about chronic folic acid
consumption. Recently another more natural form of folate, L-5-methyltetrahydrofolate
(L-MTHF) has become available. The investigators plan to conduct a randomized trial in women
to determine if supplements containing L-MTHF consumed over three months raises blood folate
levels as much as supplements containing folic acid. The investigators hypothesize that
L-MTHF will increase red cell folate over 12 weeks to same extent as equimolar folic acid.