Could high serum folate be associated with adverse effects?

Folate is an important water-soluble vitamin that is presented naturally in foods in particular vegetables, fruits, and whole grains. To which extent is this vitamin needed in our daily regimen is not fully known. Several studies have indicated that many complications, such as megaloblastic anemia, cardiovascular disease, neural tube defects, and numerous cancers, occur in humans when the body becomes deficient in folic acid. On the other hand, a few studies have shown thier concerns regarding the supplementation of folic acid, resulting in the development of existing tumors and alteration of normal patterns of DNA methylation. Although there is no clear evidence of aberrant DNA methylation and gene expression changes in response to "high" levels of folate or folic acid intake, there are still some concerns. Therefore, its adverse effects especially on fetus and later stages of life should be carefully investigated.