Dietary Recommendations

The Institute of Medicine (now known as the National Academy of Medicine) established the following Recommended Dietary Allowances (RDA) for folate:

Source: Institute of Medicine, National Academy of Sciences. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B₆, Folate, Vitamin B₁₂, Pantothenic Acid, Biotin, and Choline. Washington DC: National Academy Press; 1998.
*DFE = dietary folate equivalents.
**Women are recommended to consume 400 micrograms of folic acid from supplements or fortified foods until their pregnancy is confirmed and they begin prenatal care.

The U.S. Public Health Service and the National Academy of Medicine (formerly known as the Institute of Medicine) recommend that all women of childbearing age consume 400 micrograms of folic acid every day, from a supplement or fortified foods, in addition to consuming food folate from a varied diet. This recommendation would also apply to teenage and younger girls who have reached menses.

Family History of NTD-Affected Pregnancy

The U.S. Public Health Service recommends that women who have had a previous pregnancy affected by a neural tube defect should see their doctor because they may need a higher amount of folic acid (4 milligrams or 4000 micrograms) if planning another pregnancy. Studies have shown that taking a larger dose of folic acid daily can reduce the risk of having another affected pregnancy. Women should not try to get extra folic acid by taking more than one multivitamin per day as this might lead to unhealthy intake levels of other vitamins such as vitamin A.

Upper Level of Intake

The Institute of Medicine has established an upper level of daily intake for some nutrients, including folate. The upper level represents the daily intake amount likely to pose no risk of adverse health effects for almost all individuals. This amount is called the tolerable upper intake level (UL). The UL for folic acid for adults 19 years or older is 1000 micrograms per day from fortified foods or supplements. The UL does not include the amount of folate obtained naturally from foods (e.g., orange juice, green leafy vegetables, etc.). Individuals should be aware of the UL, especially if they take a daily supplement that contains folic acid, regularly consume fortified breakfast cereals (which can provide up to 400 micrograms of folic acid per serving), and frequently eat other fortified grain products or liquid supplements as part of their daily diet.

Concerns over the safe intake of folic acid (i.e., the synthetic form of folate found in supplements and fortified foods) at and above the Recommended Dietary Allowance (RDA) of 400 micrograms, including individuals who have genetic mutations that may impair how the body processes folate, have been raised. In 2015, the National Institutes of Health issued a report titled, "Identifying Research Needs for Assessing Safe Use of High Intakes of Folic Acid". This report summarizes the findings from an expert panel convened by the National Toxicology Program and Office of Dietary Supplements. The panel examined the issue of higher intakes of synthetic folic acid on key health outcomes and identified the research needed in this area. The report provides documentation of no concern regarding folic acid toxicity at this time. The report can be acessed here.