More details:
http://www2.le.ac.uk/offices/press/p...2013-new-study
Of course, in addition, if u have an mthfr mutation, you cannot process folic acid and must get it in the form of methylfolate. Quatrefolic is the most bioavailable form I'm told.
DNA testing with 23andme, free to pwps, reveals this very common mutation. If you're not processing folic acid effectively, you end up deficient in b12. I discovered I have this mutation and had almost run out of b12 when dx'd ten yrs ago with pd. Ldopa is also a drug mugger of b12.