How to Lower High Folate Levels Safely and Effectively

January 6, 2026 •

4 min read

Excessive folate intake, particularly from supplements and fortified foods, is a primary cause of elevated blood levels. Learning how to lower high folate levels involves a careful evaluation of dietary habits and supplement routines under medical guidance to prevent potential health risks.

Quick Summary

Identify the root cause of elevated folate, often from high-dose folic acid supplements or fortified foods. Implement dietary changes, consider alternative supplements like methylfolate, and understand risks associated with high levels and B12 deficiency.

Key Points

Identify the Cause: High folate is often due to excessive folic acid from supplements and fortified foods, or can be a sign of a masked B12 deficiency.
Adjust Supplements: Under medical guidance, reduce or stop high-dose folic acid supplements. Consider switching to methylfolate, the active form of B9.
Modify Your Diet: Limit heavily fortified foods like processed cereals and bread. Prioritize natural folate from whole food sources like leafy greens and legumes.
Test B12 Levels: Always check your vitamin B12 status along with folate, as high folate can conceal a serious B12 deficiency and its neurological effects.
Consult a Doctor: Medical supervision is essential to create a safe management plan, especially if you are pregnant, have underlying conditions, or take specific medications.
Monitor Progress: Regular blood testing after making changes can help track if your folate levels are normalizing as expected.

Understanding High Folate Levels (Hyperfolatemia)

High folate levels, medically known as hyperfolatemia, can occur when the body has an excess of vitamin B9. While folate is a crucial nutrient, excessive intake, particularly of its synthetic form, folic acid, can lead to elevated concentrations in the blood. The body’s capacity to convert synthetic folic acid into its active form, 5-methyltetrahydrofolate (5-MTHF), is rate-limiting, which can lead to a buildup of unmetabolized folic acid in the bloodstream. This condition is primarily linked to overconsumption from fortified foods and supplements, and is generally more of a concern than high intake from natural food sources.

Causes of High Folate Levels

High folate levels can arise from several sources, with the most common being:

Excessive Supplementation: Taking high-dose folic acid supplements, multivitamins, or B-complex vitamins is a frequent cause of elevated levels. Many people unknowingly consume multiple supplements containing folic acid, pushing their total daily intake far beyond the recommended amount.
Overconsumption of Fortified Foods: Since 1998, mandatory folic acid fortification of grain products like flour, cereal, and pasta in the United States and other countries has increased overall intake. This widespread fortification can contribute to high levels, especially for those who consume many of these products.
Vitamin B12 Deficiency: A low level of vitamin B12 can paradoxically cause folate to build up in the bloodstream. The body requires B12 to utilize folate, so without adequate B12, folate becomes trapped and accumulates, masking a potentially serious B12 deficiency.
Genetic Factors: Certain genetic variations, such as in the MTHFR gene, can impair the body's ability to metabolize folic acid into its active form, leading to a buildup of unmetabolized folic acid.

Strategies to Lower High Folate Levels

Managing elevated folate typically involves addressing the source of the excess rather than specific treatments for the high levels themselves.

Dietary Adjustments

Changing your diet is often the most direct way to control and lower your folate intake from food sources.

Reduce or limit consumption of heavily fortified processed foods, such as breakfast cereals, fortified breads, and pastas.
Prioritize natural, whole food sources of folate and moderate your intake if levels are significantly elevated.
Be mindful of hidden sources of folic acid in processed foods and beverages.

Supplement Adjustments

Review all your supplements to identify any containing folic acid, including multivitamins, B-complex supplements, and prenatal vitamins.
Discontinue unnecessary folic acid supplements under the guidance of a healthcare provider.
If supplementation is necessary, consider switching from synthetic folic acid to the more readily bioavailable active form, methylfolate (5-MTHF), especially if you have an MTHFR gene variant. Methylfolate does not accumulate as unmetabolized folic acid.
Monitor your levels regularly with blood tests after making supplement changes.

Addressing Underlying Conditions

Check Vitamin B12 Status: Given the risk of high folate masking a B12 deficiency, it is crucial to test both folate and vitamin B12 levels together. This may involve checking methylmalonic acid (MMA) and homocysteine levels for a more accurate assessment of B12 status.
Consult a Healthcare Provider: For persistent high levels, a doctor can investigate other potential causes, such as liver dysfunction, kidney disease, or malabsorption disorders.
Lifestyle Changes: For some, regular moderate exercise may help decrease plasma folate levels, as suggested by a study in rats.

Potential Risks of Excessive Folate

High folate levels are not typically toxic but can pose certain risks, primarily related to its interaction with vitamin B12 and other metabolic processes.

Masking B12 Deficiency: The most significant risk is that high levels of folic acid can mask the megaloblastic anemia caused by a B12 deficiency. This can allow neurological damage to progress undetected, potentially becoming irreversible.
Accelerated Mental Decline: In older adults with low B12 levels, excessive folic acid intake has been linked to accelerated age-related mental decline.
Cancer Concerns: Some studies suggest that high levels of synthetic folic acid may promote the growth of existing pre-cancerous or cancerous cells, although research on this topic is mixed and ongoing.

Folic Acid vs. Natural Folate Comparison


Feature	Synthetic Folic Acid	Natural Dietary Folate
Source	Supplements, fortified grains and cereals	Leafy greens, legumes, fruits, eggs
Absorption	Higher bioavailability, especially on an empty stomach	Absorbed less efficiently; requires digestion
Metabolism	Must be converted by dihydrofolate reductase, which can be rate-limiting	Absorbed more naturally and processed by the body
Blood Levels	Can build up as unmetabolized folic acid in the blood	Typically does not lead to high levels or buildup in healthy individuals

The Role of Vitamin B12 in Folate Metabolism

The folate and vitamin B12 relationship is complex and critical for proper cellular function. Both are essential for DNA synthesis and red blood cell production. Inadequate B12 impairs the body's ability to use folate, leading to functional folate deficiency even when blood folate levels appear high. Therefore, assessing B12 levels is a standard procedure when high folate is detected, especially if neurological symptoms are present.

Conclusion

If blood tests show elevated folate levels, the first and most critical step is a medical consultation to determine the underlying cause and rule out a masked B12 deficiency. For most people, the solution lies in a careful reassessment of dietary intake, with a focus on reducing fortified foods and high-dose supplements. Switching to methylfolate may be beneficial, particularly for those with genetic metabolic challenges. Regular monitoring and a balanced, whole-food-based approach to nutrition are key to maintaining optimal folate status without the associated risks of excess.

NIH Fact Sheet on Folate

Frequently Asked Questions

The most common causes of high folate levels (hyperfolatemia) are excessive intake of synthetic folic acid from dietary supplements and overconsumption of fortified foods.

Since folate is water-soluble, excess amounts are typically excreted through urine. Most people can expect their levels to return to normal within 2-4 weeks after reducing or stopping supplementation, though this can vary.

Yes, high levels of folic acid can mask the blood changes (megaloblastic anemia) associated with a vitamin B12 deficiency, potentially allowing nerve damage to advance unnoticed.

While folate toxicity is rare, consistently high levels can mask a vitamin B12 deficiency, cause digestive upset, sleep problems, and have been linked to an increased risk of certain cancers in some studies.

Folate is the naturally occurring form of vitamin B9 found in foods, while folic acid is the synthetic form used in supplements and fortified foods. The body processes and metabolizes them differently.

You should not stop supplementation without consulting a healthcare provider, especially if you are pregnant or have a medical condition. A doctor can help you safely adjust your intake.

Yes, switching from synthetic folic acid to methylfolate (5-MTHF) is often recommended, particularly for individuals who have difficulty metabolizing folic acid. Methylfolate does not accumulate in the same way as unmetabolized folic acid.

Vitamin B12 is essential for the body to utilize folate properly. A deficiency in B12 can cause folate to become trapped and accumulate in the blood, leading to high readings despite functional deficiency.