Upper Limits For Folic Acid Intake

Folic acid is the synthetic form of vitamin B9, or folate. Your body requires vitamin B9 to manufacture new cells, making this micronutrient an essential cofactor in red blood cell production. Vitamin B9 is also critically important during pregnancy to ensure normal formation and development of the baby's nervous system. Although folate from your diet is nontoxic, excessive intake of folic acid supplements may lead to medical problems. The recommended upper limit for folic acid intake among adults is 1,000 mcg daily.

Folic Acid, B12 and Nerve Damage

Folate and vitamin B12 are distinctly different chemicals. Both of these B vitamins, however, participate in many of the same biological processes. For this reason, extremely high or low levels of one of these vitamins may affect the activity of the other. A deficiency of either vitamin B12 or folate, for example, leads to anemia and microscopically identical abnormalities of your red blood cells. Similarly, the Institute of Medicine reports that excess folic acid supplementation may provoke or worsen nerve damage associated with a vitamin B12 deficiency. The IOM recommends an upper intake level of 1,000 mcg of folic acid daily for adults, primarily to prevent potential nerve damage among people with an unrecognized vitamin B12 deficiency.

Reduced Efficacy of Antiseizure Medication

The National Institutes of Health reports that increased seizure frequency is a possible side effect of excessive folic acid intake among patients taking antiseizure medication. The likelihood of this side effect may increase in parallel with the amount of folic acid you consume. If you take medication to control seizures, talk with your doctor before taking folic acid supplements to make sure they are safe for you.

Skin Reactions

Although uncommon, skin reactions have been reported in association with folic acid supplements, including hives, itching, skin redness and rashes. It is unclear whether these reactions represent a nonallergic reaction or an allergic response to folic acid or impurities in the supplements. Talk with your doctor if you experience any of these symptoms after taking a folic acid supplement.

Prevention

Consuming the recommended amount of folate from foods in your diet circumvents the need for supplemental folic acid and eliminates possible associated risks. The recommended daily allowance of folate for adults is 400 mcg; pregnancy and breastfeeding increase your daily requirement to 600 mcg and 500 mcg, respectively. Good sources of folate to incorporate into your nutrition plan include breakfast cereal, bread, pasta, enriched rice, crackers, spinach, asparagus, dry beans, okra, beets, collards, greens, lettuce, liver, broccoli, Brussels sprouts, cauliflower and avocados.