Unmetabolized Folic Acid in Plasma is associated with Reduced Natural Killer Cell Cytotoxicity among Postmenopausal Women.
Given that I am a big fan of folic acid supplementation, articles like this do cause me to slow down an re-evaluate what I’m doing. A few things to consider. Some supplements do use the form 5-tetrahydrofolate, which is the converted form, which is not a bad idea. However, you can run into problems when a patient is loaded up on folic acid (such as with food fortification) but not given adequate levels of B12 to go with it.
These two, along with betaine and B6, run in the same circles. So, if one is going to consider supplementation of folic acid, there needs to be an adequete level of B12 given. This is NOT found in pharmaceutical prenatals, which have very low levels of B12.
