Folate, also known as vitamin B9, is a water-soluble nutrient essential for DNA synthesis, cell growth, and red blood cell formation. While adequate intake is important for health, particularly during periods of rapid growth like pregnancy, elevated levels can occur and require investigation.
Understanding Folate and Elevated Levels
Folate exists in two primary forms: natural folate found in various foods and synthetic folic acid, used in dietary supplements and to fortify certain foods. The body requires folate for DNA and RNA production, and for the metabolism of amino acids necessary for cell division. Because the body cannot produce folate, it must be obtained through diet or supplementation.
Serum folate concentrations are commonly measured in blood tests to assess an individual’s folate status. A typical normal range for serum folate is between 2 to 20 nanograms per milliliter (ng/mL). Levels exceeding 20 ng/mL are considered elevated, with some definitions marking levels above 24 ng/mL as definitively high. Normal ranges can vary slightly between different laboratories.
Common Reasons for High Folate
Excessive intake of synthetic folic acid is a frequent cause of elevated folate levels. This can occur from high-dose folic acid supplements, particularly amounts greater than 800 micrograms (µg) daily, or unknowingly taking multiple supplements like multivitamins.
Another significant contributor to high folate is the consumption of foods fortified with folic acid. In many countries, including the United States, grain products like cereals, bread, and pasta are enriched with folic acid to prevent deficiencies. While natural folate-rich foods like leafy greens, legumes, and citrus fruits contribute to overall intake, they are less likely to cause significant elevation on their own.
A severe vitamin B12 deficiency can also lead to elevated folate levels in the blood. This occurs because folate metabolism is closely linked with vitamin B12. Without enough B12, folate becomes “trapped” in a form that cannot be properly utilized by the body, leading to its accumulation in the bloodstream.
Genetic variations, such as polymorphisms in the MTHFR gene, can affect how the body metabolizes folate. These variations might lead to altered blood levels, although they are generally a less direct cause of high folate compared to excessive supplementation or B12 deficiency. Certain medical conditions like liver disease or inflammatory disorders may also be associated with elevated folate.
Potential Health Considerations of Elevated Folate
A primary concern with chronically high folate levels is their ability to mask a vitamin B12 deficiency. High folate can correct the anemia often seen in B12 deficiency, but it does not address the underlying B12 deficit. This masking effect can delay the diagnosis and treatment of B12 deficiency, potentially leading to irreversible neurological damage.
While high folate levels often do not cause distinct symptoms on their own, any symptoms experienced are more likely related to underlying causes like B12 deficiency. Some individuals with high folate have reported digestive upset, difficulty concentrating, or sleep problems, and other potential impacts are under ongoing research.
Unmetabolized folic acid (UMFA), which can accumulate with high synthetic folic acid intake, has been linked to altered immune responses and possible effects on brain function. The relationship between high folate and cancer risk remains an area of ongoing research, with some studies suggesting a potential increase in risk with very high doses of folic acid, while others show neutral or protective effects. The impact on cognitive function is also complex, with some studies suggesting a possible negative effect when high folate is combined with low B12, while others indicate no adverse impact or even benefit with normal B12 levels.
What to Do If Your Folate is High
If a blood test reveals elevated folate levels, consulting a healthcare professional is an important first step. A doctor can provide diagnosis and guidance tailored to individual circumstances, and it is essential to discuss all medications and supplements being taken, as some can affect test results.
The doctor will likely order additional tests, particularly to check vitamin B12 levels, to rule out a deficiency. Testing for homocysteine levels may also be recommended, as it can provide further insight into folate and B12 status.
Under medical supervision, it may be advisable to review and potentially reduce or discontinue folic acid supplements. Evaluating the intake of fortified foods and high-folate natural foods can help in managing levels. Any adjustments to diet or supplementation should be made with professional medical guidance, as treatment depends on identifying and addressing the underlying cause of the elevated folate.