Hi avigilad100,
Folic acid is not recommended for those with MTHFR mutations (SNPs).
The following article http://www.mthfrsupport.com.au/folic-acid-vs-5-mthf-treating-mthfr-deficiency/ written by Carolyn Ledowsky ND, founder of MTHFR Support Australia who collaborates with Sterling Hill founder of MTHFR Support, creator of Sterling’s App and owner of this website provides much information about why folic acid should be avoided.
At the end of the article in the Bibliography you will find links to articles supporting Carolyn’s views which are shared by many practitioners and researchers in this field including Sterling Hill.
Lea