What are the Dietary Reference Intakes for folate?
Recommendations for folate are given in the Dietary Reference Intakes (DRIs) developed by the Institute of Medicine of the National Academy of Sciences. Dietary Reference Intakes is the general term for a set of reference values used for planning and assessing nutrient intake for healthy people. Three important types of reference values included in the DRIs are Recommended Dietary Allowances (RDA), Adequate Intakes (AI), and Tolerable Upper Intake Levels (UL). The RDA recommends the average daily intake that is sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals in each age and gender group. An AI is set when there is insufficient scientific data available to establish a RDA. AIs meet or exceed the amount needed to maintain a nutritional state of adequacy in nearly all members of a specific age and gender group. The UL, on the other hand, is the maximum daily intake unlikely to result in adverse health effects.
The RDAs for folate are expressed in a term called the Dietary Folate Equivalent. The Dietary Folate Equivalent (DFE) was developed to help account for the differences in absorption of naturally occurring dietary folate and the more bioavailable synthetic folic acid. Table 2 lists the RDAs for folate, expressed in micrograms (mcg) of DFE, for children and adults.
Table 2: Recommended Dietary Allowances for Folate for Children and Adults
Age
(years) |
Males and Females
(mcg/day) |
Pregnancy
(mcg/day) |
Lactation
(mcg/day) |
| 1-3 |
150 |
N/A |
N/A |
| 4-8 |
200 |
N/A |
N/A |
| 9-13 |
300 |
N/A |
N/A |
| 14-18 |
400 |
600 |
500 |
| 19+ |
400 |
600 |
500 |
*1 DFE = 1 food folate = 0.6 folic acid from supplements and fortified foods
There is insufficient information on folate to establish an RDA for infants. An Adequate Intake (AI) has been established that is based on the amount of folate consumed by healthy infants who are fed breast milk. Table 3 lists the Adequate Intake for folate , in micrograms (mcg), for infants.
Table 3: Adequate Intake for folate for infants
Age
(months) |
Males and Females
(mcg/day) |
| 0 to 6 |
65 |
| 7 to 12 |
80 |
The National Health and Nutrition Examination Survey (NHANES III 1988-94) and the Continuing Survey of Food Intakes by Individuals (1994-96 CSFII) indicated that most individuals surveyed did not consume adequate folate. However, the folic acid fortification program, which was initiated in 1998, has increased folatefolic acid content of commonly eaten foods such as cereals and grains, and as a result most diets in the United States (US) now provide recommended amounts of folate equivalents.
When can folate deficiency occur?A deficiency of folate can occur when an increased need for folate is not matched by an increased intake, when dietary folate intake does not meet recommended needs, and when folate excretion increases. Medications that interfere with the metabolism of folate may also increase the need for this vitamin and risk of deficiency.
Medical conditions that increase the need for folate or result in increased excretion of folate include:
- pregnancy and lactation (breastfeeding)
- alcohol abuse
- malabsorption
- kidney dialysis
- liver disease
- certain anemias
Medications that interfere with folate utilization include:
- anti-convulsant medications (such as dilantin, phenytoin and primidone)
- metformin (sometimes prescribed to control blood sugar in type 2 diabetes)
- sulfasalazine (used to control inflammation associated with Crohn's disease and ulcerative colitis)
- triamterene (a diuretic)
- methotrexate (used for cancer and other diseases such as rheumatoid arthritis)
- barbiturates (used as sedatives)
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