Folic Acid Toxicity

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(70)91845-3/fulltext

https://www.sciencedirect.com/science/article/pii/S0140673670918453

More and more people are considering themselves glutin intolerate, but these people do not have Celiac disease.  So why are increasingly many people sensitive to wheat products?  It may be the folic acid enrichment.   Active folate is methylfolate. The Europeam study above reveals that a related compound folic acid may interfere with active folate and B12 (methylcobalamin) function.  The study above had to be stopped only after 1 month due to neuro toxicity. 

https://www.ncbi.nlm.nih.gov/m/pubmed/2667316/

https://www.ncbi.nlm.nih.gov/m/pubmed/3946290/?i=6&from=/2667316/related

These studies suggest that folic acid inhibits zinc absorption. 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3738454/

Zinc deficiency is associated with anxiety.

https://www.frontiersin.org/articles/10.3389/fnmol.2018.00405/full

Maternal zinc deficiency (exacerbated by folic acid supplementation) is associated wity autism.