Folate

Folate (folic acid)

Age

Recommended dietary allowance (mcg)

Tolerable upper intake level (mcg)

Children 0-6 mos.

65 (AI)

Not established

Children 7-12 mos.

80 (Al)

Not established

Children 1-3 yrs.

150

300

Children 4-8 yrs.

200

400

Children 9-13 yrs.

300

600

Children 14-18 yrs.

400

800

Adults 19+ yrs.

400

1,000

Pregnant women 14-18 yrs.

600

800

Pregnant women 19+ yrs.

600

1,000

Breastfeeding women 14-18 yrs.

500

800

Breastfeeding women 19+ yrs.

500

1,000

AI = Adequate Intake

mcg = microgram

SOURCE: Office of Dietary Supplements. National Institutes of Health. Folate: Fact Sheet for Health Professionals. U.S. Department of Health and Human Services. Last modified March 2, 2018. https://ods.od.nih.gov/factsheets/Folate-HealthProfessional (accessed April 4, 2018).

Definition

Selected food sources of folate and folic acid

Food

Micrograms (HQ)

% daily value

*Breakfast cereals fortified with 100% of the DV, ¾ cup

400

100

Beef liver, cooked, braised, 3 oz.

215

54

Lentils, mature seeds, cooked, boiled, ½ cup

179

45

Spinach, frozen, cooked, boiled, ½ cup

115

29

*Egg noodles, cooked, enriched, ½ cup

110

28

*Breakfast cereals, fortified with 25% of the DV, ¾ cup

100

23

Great Northern beans, boiled, ½ cup

90

23

Asparagus, boiled, 4 spears

89

22

*Macaroni, cooked, enriched, ½ cup

84

21

*Rice, white, long-grain, enriched, cooked, ½ cup

77

19

Avocado, raw, all varieties, sliced, ½ cup

59

15

Spinach, raw, 1 cup

58

15

Papaya, raw, 1 cup cubes

52

13

Corn, sweet, yellow, canned ½ cup

52

13

Broccoli, chopped, frozen, cooked, ½ cup

51

13

Tomato juice, canned, 1 cup

49

12

Green peas, frozen, boiled, ½ cup

47

12

Orange juice, chilled, includes concentrate, 1 cup

47

12

*Bread, white, 1 slice

43

11

Peanuts, all types, dry roasted, 1 oz.

41

10

Broccoli, raw, 2 spears (each 5 in. long)

40

10

Wheat germ, crude, 2 Tbsp.

40

10

Strawberries, raw, 1 cup

40

10

Cantaloupe melon, raw, 1 cup cubes

34

9

Lettuce, romaine, shredded, ½ cup

32

8

Vegetarian baked beans, canned, 1 cup

30

8

Orange, all commercial varieties, fresh, 1 small

29

7

Egg, whole, raw, fresh, 1 large

24

6

Banana, raw, 1 medium

24

6

*Bread, whole wheat, 1 slice

14

4

*Items are fortified with folic acid as part of the Folate Fortification Program.

SOURCE: U.S. Department of Agriculture (USDA) Agricultural Research Service, National Nutrient Database for Standard Reference, Release 24.

Purpose

Folate is necessary to create new DNA (genetic material) and RNA when cells divide. It plays a critical role in developing healthy red blood cells. Folate also helps protect DNA from damage that may lead to diseases such as cancer. Along with vitamins B6 and B12, folate helps regulate the level of the amino acid homocysteine in the blood. Homocysteine regulation is related to cardiovascular health. In the fetus, folate is necessary for the proper development of the brain and spinal cord.

Description

Folate is one of eight B-complex vitamins. Its function is closely intertwined with that of vitamins B6 and B12. Folate, from the Latin word folium, meaning leaf, was discovered in the late 1930s in yeast, and later found in spinach and other green leafy vegetables and in liver. Starting in 1998, the U.S. Food and Drug Administration (FDA) required certain foods, such as flour, corn meal, bread, cereal, rice, and pasta, to be fortified with a folic acid. In Canada and Chile, fortification of flour is mandatory.

Folate's role in health

Folate is essential for the normal development of the neural tube in the fetus. The neural tube develops into the brain and spinal cord. It closes between the third and fourth week after conception. Too little folate at this time can lead to serious malformations of the spine (spina bifida) and the brain (anencephaly). Because many women do not realize that they are pregnant so soon after conception, the United States has included folic acid in its fortified foods program. Adding folic acid to common foods made with grains has substantially reduced the number of babies born with neural tube defects in the United States.

The body also needs folate to produce healthy red blood cells. When not enough folate is present, the red blood cells do not divide and instead grow to be abnormally large. These malformed cells have a reduced ability to carry oxygen to other cells in the body, a condition known as megaloblastic anemia. Folate also aids in the production of other new cells. Adequate supplies of folate are especially important in fetuses and infants because they are growing rapidly, but, since the life span of a red blood cell is only about four months, both children and adults need a continuous supply of folate throughout life to create healthy new replacement blood cells.

Folate acts together with vitamin B6 and vitamin B12 to lower the level of homocysteine in the blood. Homocysteine is an amino acid that is naturally produced when the body breaks down protein. Moderate to high levels of homocysteine in the blood are potentially linked to an increased risk of cardiovascular disease (e.g., atherosclerosis, heart attack, stroke). The trio of folate, vitamin B6, and vitamin B12 lower homocysteine levels. However, it is not clear whether taking large doses of these vitamins, either alone or in combination, will prevent heart disease from developing in healthy individuals. The official position of the American Heart Association in 2012 stated, “We don't recommend widespread use of folic acid and B vitamin supplements to reduce the risk of heart disease and stroke. We advise a healthy, balanced diet that's rich in fruits and vegetables, whole grains, and fat-free or low-fat dairy products.”

Damage to DNA appears to contribute to the development of many different cancers. Because folate helps protect against DNA damage, researchers have looked at whether it can reduce the risk of developing cancer. Results are mixed, with benefits seen for some cancers but not for others. The American Cancer Society position in 2012 was as follows: “Low levels of folic acid in the blood have been linked with higher rates of colorectal cancer and some other types of cancer, as well as with certain birth defects. It is not clear whether consuming recommended (or higher) amounts of folic acid—from foods or in supplements—can lower cancer risk in some people. These issues are being studied. High doses of folic acid can interfere with the action of some chemotherapy drugs, such as methotrexate.”

Many clinical trials are underway to determine the safety and effectiveness of folate, both alone and in combination with other vitamins, in preventing cancer, cardiovascular disease, and dementias, such as Alzheimer's disease. Research is also underway on the effect of folate on schizophrenia and the feasibility of including folate in birth control pills. Individuals interested in participating in a clinical trial at no charge can find a list of open trials at http://www.clinicaltrials.gov .

Sources of folate

People need a continuous supply of folate from their diet because of the role it plays in creating new blood cells. Because folate is water-soluble, little is stored in the body, and any excess is excreted in urine. Since the folic acid fortification program began in 1998, most healthy Americans get enough folate from their diet. The exception is pregnant women who should, under medical supervision, take a folic acid supplement (400 mcg for most women and higher doses for those who have already had a baby with a neural tube defect). Good natural sources of folate include beef liver, green leafy vegetables, and dried beans. Cooking animal products does not reduce the folate content much, but cooking vegetables can reduce the amount of folate by up to 40%, depending on the vegetable and the cooking method.

The following list gives the approximate folate content of some common foods:

KEY TERMS
Alzheimer's disease—
An incurable disease of older individuals that results in the destruction of nerve cells in the brain and causes gradual loss of mental and physical functions.
Amino acid—
Molecules that are the basic building blocks of proteins.
B-complex vitamins—
A group of water-soluble vitamins that often work together in the body. These include thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7 or vitamin H), folate (B9), and cobalamin (B12).
Celiac disease—
A chronic digestive disorder in which eating foods that contain the protein gluten (found in wheat flour, rye, and barley) causes an immune reaction that damages the small intestine and interferes with the absorption of food.
Deoxyribonucleic acid (DNA)—
The genetic material in cells that holds the inherited instructions for growth, development, and cellular functioning.
Dietary supplement—
A product—such as a vitamin, mineral, herb, amino acid, or enzyme—that is intended to be consumed in addition to an individual's diet with the expectation that it will improve health.
Diuretic—
A substance that removes water from the body by increasing urine production.
Enzyme—
A protein that changes the rate of a chemical reaction within the body without being depleted in the reaction.
Megaloblastic anemia—
A type of anemia characterized by abnormally large red blood cells; usually caused by folate or vitamin B12 deficiencies.
Ribonucleic acid (RNA)—
A molecule that helps decode genetic information (DNA) and is necessary for protein synthesis.
Water-soluble vitamin—
A vitamin that dissolves in water and can be removed from the body in urine.

Recommended dosage

The U.S. Institute of Medicine (IOM) of the National Academy of Sciences has developed values called Dietary Reference Intakes (DRIs) for vitamins and minerals. The DRIs consist of three sets of numbers. The recommended dietary allowance (RDA) defines the average daily amount of the nutrient needed to meet the health needs of 97%–98% of the population. The adequate intake (AI) is an estimate set when there is not enough information to determine an RDA. The tolerable upper intake level (UL) is the average maximum amount that can be taken daily without risking negative side effects. The DRIs are calculated for children, adult men, adult women, pregnant women, and breastfeeding women.

The IOM has not set RDAs for folate in children under one year old because of incomplete scientific information. Instead, it has set AI levels for this age group. RDAs and ULs for folate are measured in micrograms (mcg). Unlike the UL for many vitamins, the UL for folate refers only to folic acid that comes from fortified food or that is in folic acid dietary supplements, multivitamins, or B-complex vitamins. There is no UL for folate found in natural plant and animal foods. Dietary supplements containing more than 1,000 mcg (1 mg) of folic acid require a prescription. One mcg of folate from natural food sources is equal in biological activity in humans to 0.6 mcg of folic acid from supplements or fortified food.

The following are the daily RDAs and AIs and ULs for folic acid for healthy individuals:

Precautions

Since many pregnancies are unplanned and unrecognized until after the critical period for brain and spinal cord formation, any woman who may become pregnant should be careful to include enough folate in her diet, and folic acid supplements should be taken before and in the first trimester of pregnancy.

QUESTIONS TO ASK YOUR DOCTOR

Folic acid may mask vitamin B12 deficiency. Folic acid supplements will reverse anemia symptoms, but they do not stop nerve damage caused by B12 deficiency. Permanent nerve damage may result. People with suspected folate deficiency who begin taking folic acid supplements should also be evaluated for vitamin B12 deficiency.

Interactions

The following is a partial list of medications that may interfere with the ability of the body to absorb and use folate. Individuals taking these medications should check with their physician about the effects they may have on folate levels in the body:

Complications

No complications are expected when folate or folic acid is taken within recommended levels.

Folate deficiency

Most healthy people in the United States get enough folate in their diet because folate is added to many common foods, such as bread; however, this is not the case elsewhere. In Europe, low intakes are commonly reported, particularly in teenage girls and older people. Causes of folate deficiency include inadequate intake, impaired absorption (celiac disease, Crohn's disease, certain medications), inability of the body to use folate (enzyme deficiencies), increased folate needs (pregnancy, cancer), or increased loss or excretion (kidney dialysis, alcoholism). The elderly are the largest group at risk to develop folate deficiency.

The major symptom of folate deficiency in pregnant women is having a baby born with a brain or spinal cord abnormality. Other symptoms of folate deficiency include slow growth in infants and children; megaloblastic anemia; digestive problems, such as diarrhea; sore tongue; irritability; forgetfulness; and changes in mental state. These changes also have other causes and should be evaluated by a healthcare professional.

Folate overdose

Complications of excess folic acid intake at levels above 1,000 mcg daily over an extended period can include seizures in individuals taking anticonvulsant medications and general irritability and restlessness in otherwise healthy individuals.

Parental concerns

Parents need to be aware that infants and rapidly growing children are at higher risk for folate deficiency. Parents of children with digestive disorders or allergies to wheat products (e.g., celiac disease) should discuss the need for a folic acid supplement with their pediatrician.

See also Adult nutrition ; Alcohol consumption ; Cancer-fighting foods ; Celiac disease ; Crohn's disease ; Fad diets ; Nutrigenomics ; Vitamin B6 ; Vitamin B12 ; Vitamins ; Whole grains .

Resources

BOOKS

Bailey, Lynn B., ed. Folate in Health and Disease. 2nd ed. Boca Raton, FL: CRC Press/Taylor & Francis, 2010.

Mason, Pamela. Dietary Supplements. 4th ed. Chicago: Pharmaceutical Press, 2011.

Webb, Geoffrey P. Dietary Supplements and Functional Foods. Chichester, West Sussex; Ames, IA: Wiley-Blackwell, 2011.

PERIODICALS

de Lourdes Samaniego-Vaesken, María, Elena Alonso-Aperte, and Gregorio Varela-Moreiras. “Vitamin Food Fortification Today.” Food & Nutrition Research 56 (April 2, 2012). http://dx.doi.org/10.3402/fnr.v56i0.5459 (accessed March 29, 2018).

Kennedy, Deborah, and Gideon Koren. “Identifying Women Who Might Benefit from Higher Doses of Folic Acid in Pregnancy.” Canadian Family Physician 58, no. 4 (April 2012): 394–97.

Xun, Pengcheng, et al. “Folate Intake and Incidence of Hypertension among American Young Adults: A 20-Year Follow-Up Study.” American Journal of Clinical Nutrition 95, no. 5 (May 1, 2012): 1023–30. http://dx.doi.org/10.3945/ajcn.111.027250 (accessed March 29, 2018).

WEBSITES

Coffey-Vega, Katherine, et al. “Folic Acid Deficiency.” Medscape. Updated July 19, 2017. http://emedicine.medscape.com/article/200184-overview (accessed March 29, 2018).

Higdon, Jane, Victoria J. Drake, and Barbara Delage. “Folic Acid.” Linus Pauling Institute, Oregon State University. May 9, 2011. http://lpi.oregonstate.edu/infocenter/vitamins/fa (accessed March 29, 2018).

MedlinePlus. “Folic Acid.” U.S. National Library of Medicine, National Institutes of Health. https://medlineplus.gov/folicacid.html (accessed March 29, 2018).

Office of Dietary Supplements. “Dietary Supplement Fact Sheet: Folic Acid.” National Institutes of Health. http://ods.od.nih.gov/factsheets/Folate-HealthProfessional (accessed March 29, 2018).

ORGANIZATIONS

Academy of Nutrition and Dietetics, 120 South Riverside Plz., Ste. 2000, Chicago, IL, 60606-6995, (312) 899-0040, (800) 877-1600, amacmunn@eatright.org, http://www.eatright.org .

Linus Pauling Institute, Oregon State University, 307 Linus Pauling Center, Corvallis, OR, 97331, (541) 737-5075, Fax: (541) 737-5077, http://lpi.oregonstate.edu .

Office of Dietary Supplements, National Institutes of Health, 6100 Executive Blvd., Rm. 3B01, MSC 7517, Bethesda, MD, 20892-7517, (301) 435-2920, Fax: (301) 480-1845, ods@nih.gov, http://ods.od.nih.gov .

Revised by Tish Davidson, AM

  This information is not a tool for self-diagnosis or a substitute for professional care.