Millions of patients have a MTHF-reductase gene defect making them less able to convert folic acid into MTHF (active folate). This puts them at high risk of folic insufficient health conditions.
Combine this with anti-folate drug therapies, that can lower efficacy of folic acid such as Methotrexate, Sulfasalazine, there is a big concern. I routinely test all my patients, with high normal MCV, homocysteine, or mental health concerns.
CONCLUSIONS:
The high proportion of 5-MTHF in the epidermis, which is further emphasized in subjects with a lower (10-20-nM) serum folate status, points to a special role for this form of folate in skin, perhaps as a protectant from ultraviolet-induced photosensitization reactions. 5-MTHF may also maintain methylation reactions that influence the proliferative activity. These results may help to individualize the treatment of psoriasis patients with methotrexate and folate.
Am J Clin Nutr. 2013 May 15. Effect of serum folate status on total folate and 5-methyltetrahydrofolate in human skin.
Abstract
BACKGROUND:
It has been suggested that human skin color adapts to balance the need for vitamin D synthesis in comparison with the protection of DNA and folate from photodegradation. However, the folate content of human skin is unknown and may affect the effectiveness of the antifolate methotrexate for the treatment of psoriasis.
