From the Guidelines
You can overdose on folate, and it is recommended to keep total daily folate consumption at less than 1 mg per day to avoid potential complications. The effects of higher doses of folic acid are not well known, but they can include complicating the diagnosis of vitamin B12 deficiency in certain people, which may lead to irreversible neurologic damage if left untreated 1. Folic acid is a water-soluble vitamin, and any excess consumed is rapidly excreted in the urine. However, excessive consumption of folic acid supplements or fortified foods can cause adverse effects.
- Key points to consider:
- The recommended daily allowance (RDA) for folic acid is 0.4 mg for nonpregnant women and 0.4 to 0.8 mg per day for pregnant women 1.
- Women should be careful not to exceed the recommended amount to avoid excessive consumption, which may lead to adverse effects.
- It is essential to consult with a healthcare provider or a registered dietitian to determine the best way to obtain the recommended amount of folic acid while avoiding excessive consumption.
- Natural folate from food sources is generally considered safe, but synthetic folic acid supplements and fortified foods should be consumed with caution.
- Exceeding the recommended daily intake of folic acid may cause symptoms like nausea, abdominal cramps, sleep disturbances, irritability, and confusion, and may also mask vitamin B12 deficiency, leading to neurological damage.
From the FDA Drug Label
Precaution Folic Acid in doses above 0.1 mg daily may obscure pernicious anemia in that hematologic remission can occur while neurological manifestations remain progressive. The FDA drug label does not answer the question.
From the Research
Folate Overdose
- Folate is an essential nutrient, but excessive intake can have adverse effects 2.
- High doses of folic acid (10 mg/day) have been reported to cause a significant decline in cognitive function tasks in demented patients 3.
- Elevated folate status resulting from high folic acid intake may affect vitamin B-12 function and its roles in sustaining health 4.
- Excess folate intake can mask vitamin B-12 deficiency, delaying diagnosis and potentially leading to irreversible neurologic damage 3, 5.
Health Risks Associated with Excess Folate
- High folic acid intake has been linked to potential adverse effects on cancer risk, birth outcomes, and other diseases 2.
- An imbalance of high folate status and low vitamin B-12 status is associated with negative health outcomes in older adults and children 4.
- Excessive folic acid supplementation during pregnancy may alter the optimal ratio of folates to vitamin B-12, inducing changes in gene methylation and metabolic pathways, affecting fetal development and long-term health 6.
Folate Intake and Supplementation
- The recommended upper limit for folate intake is 1,000 microg/day, and excessive intake can occur with high-dose supplements 5.
- Folate fortification of foods, such as bread and grains, can increase folate intake, but may also pose a risk for the elderly due to the potential for masking vitamin B-12 deficiency 5.
- Dietitians should be aware of modern protocols for screening the elderly for vitamin B-12 deficiency to prevent irreversible neurologic damage 5.