This is to address your questions regarding folic acid, whatever the form.
You may have read that taking the active form of folic acid is absorbed (which is the same form as in foods) but:
The active form (polyglutamated form) cannot be absorbed in the intestine. To be absorbed, it must have the glutamates removed (except the one that is an integral part of folate) by the enzyme gamma-glutamyl hydrolase (also called conjugase), so it would not be useful to take this form.
Once absorbed and taken through the intestines into the body, the glutamates are added on. It is also reduced to the tetrahydrofolate form . (Here is where it uses a riboflavin enzymes to reduce it.)
Hence, any form of folic acid will require riboflavin to reduce it.
Hi, dog person.
As I understand it, folic acid is the oxidized form of folate, and to be used in the body it must be reduced to tetrahydrofolate. However, this is done by two sequential reactions catalyzed by DHFR (dihydrofolate reductase), which requires NADPH, but does not require riboflavin.
The active forms of folate that are found in natural foods, which are mainly 5-methyltetrahydrofolate and folinic acid are already reduced, and do not require riboflavin or anything else to reduce them. The gut normally has no difficulty removing the extra glutamates and absorbing the natural folate forms, using the enzyme you mentioned.
You may be thinking of the MTHFR enzyme, which converts 5,10 methylene tetrahydrofolate to 5-methyltetrahydrofolate. This enzyme does require FAD as a cofactor, which is one of the two coenzyme forms of riboflavin.
I continue to read your posts with interest. I would like to better understand the metabolism of the minerals and the interpretation of the various tests taken together: hair mineral analysis, urine toxic and essential element analysis, fecal mineral analysis, and blood mineral analyses (RBC, whole blood and plasma). It would be great to be able to make sense of all these.
Best regards,
Rich