High folate levels in the blood serum can be the result of a B12 deficiency, explains WebMD. Additionally, eating a diet that is rich in folic acid or taking vitamins or supplements containing folic acid can increase blood serum levels of folate.
Folic acid can accumulate in the blood as a result of having a B12 deficiency because the body’s cells require B12 to utilize folic acid, reports WebMD. A person’s recent diet can also affect the level of folate measured in blood serum, states Lab Tests Online. Eating foods such as leafy vegetables, broccoli and okra can increase folic acid levels in the blood. However, consuming more folic acid than the body requires is not harmful, according to WebMD.