folate

What can high-folate foods do for you?

  • Support red blood cell production and help prevent anemia
  • Help prevent homocysteine build-up in your blood
  • Support cell production, especially in your skin
  • Allow nerves to function properly
  • Help prevent osteoporosis-related bone fractures (June 3, 2004)
  • Help prevent dementias including Alzheimer's disease(June 30, 2004)

What events can indicate a need for more high-folate foods?

  • Irritability
  • Mental fatigue, forgetfulness, or confusion
  • Depression
  • Insomnia
  • General or muscular fatigue
  • Gingivitis or periodontal disease

Excellent sources of folate include romaine lettuce, spinach, asparagus, turnip greens, mustard greens, calf's liver, parsley, collard greens, broccoli, cauliflower, beets, and lentils.

 

Description

What is folate?

Folic acid, also called folate or folacin, is a B-complex vitamin most publicized for its importance in pregnancy and prevention of pregnancy defects. These defects involve malformation of a structure in the fetus called the neural tube. As the baby develops, the top part of this tube helps form the baby's brain, and the bottom part unfolds to become the baby's spinal column.

When the neural tube fails to close properly, serious brain and spinal problems result. Mothers with inadequate supplies of folic acid have been determined to give birth to a greater number of infants with neural tube defects. Beginning in the early 1980's, researchers began to successfully use folic acid supplementation to reduce the risk of nervous system problems in newborn infants.

Folic acid is one of the most chemically complicated vitamins, with a three-part structure that puts special demands on the body's metabolism. The three primary components of folic acid are called PABA, glutamic acid, and pteridine. (Two of these components, glutamic acid and pteridine, help explain the technical chemical name for folate, namely pteroylmonoglutamate.)

As complex as this vitamin is in its structure, it is equally as complicated in its interaction with the human body. For example, most foods do not contain folic acid in the exact form described above, and enzymes inside the intestine have to chemically alter food forms of folate in order for this vitamin to be absorbed. Even when the body is operating at full efficiency, only about 50% of ingested food folate can be absorbed.

How it Functions

What is the function of folate?

Red blood cell formation and circulation support

One of folate's key functions as a vitamin is to allow for complete development of red blood cells. These cells help carry oxygen around the body. When folic acid is deficient, the red bloods cannot form properly, and continue to grow without dividing. This condition is called macrocytic anemia, and one of its most common causes is folic acid deficiency.

In addition to its support of red blood cell formation, folate also helps maintain healthy circulation of the blood throughout the body by preventing build-up of a substance called homocysteine. A high serum homocysteine level (called hyperhomocysteinemia) is associated with increased risk of cardiovascular disease, and low intake of folate is a key risk factor for hyperhomocysteinemia. Increased intake of folic acid, particularly by men, has repeatedly been suggested as a simply way to lower risk of cardiovascular disease by preventing build-up of homocysteine in the blood. Preliminary research also suggests that high homocysteine levels can lead to the deterioration of dopamine-producing brain cells and may therefore contribute to the development of Parkinson's disease. Therefore, folate deficiency may have an important relationship to neurological health.

Research is now confirming a link between blood levels of folate and not only cardiovascular disease, but dementias, including Alzheimer's disease.

One of the most recent studies, which was published in the July 2004 issue of the American Journal of Clinical Nutrition evaluated 228 subjects. In those whose blood levels of folate were lowest, the risk for mild cognitive impairment was more than tripled, and risk of dementia increased almost four fold. Homocysteine, a potentially harmful product of cellular metabolism that is converted into other useful compounds by folate, along with vitamin B6 and B 12, was also linked to dementia and Alzheimer's disease. Individuals whose homocysteine levels were elevated had a 4.3 (more than four fold) increased risk of dementia and a 3.7 (almost four fold) increased risk of Alzheimer's disease.(June 30, 2004)

Research teams in the Netherlands and the U.S. have confirmed that low levels of folic acid in the diet significantly increases risk of osteporosis-related bone fractures due to the resulting increase in homocysteine levels. Homocysteine has already been linked to damage to the arteries and atherosclerosis, plus increased risk of dementia in the elderly. Now, in a study that appeared in the May 2004 issue of the New England Journal of Medicine, researchers at the Eramus Medical Center, Rotterdam, Holland, and another team in Boston have confirmed that individuals with the highest levels of homocysteine have a much higher risk of osteoporotic fracture.

In the Rotterdam study, which included 2,406 subjects aged 55 years or older, those with the highest homocysteine levels, whether men or women, almost doubled their risk of fracture. The Boston team found that risk of hip fracture nearly quadrupled in men and doubled in women in the top 25% of homocysteine levels.

Both groups found that folic acid reduced the risk of osteoporotic fractures by reducing high levels of homocysteine. While the researchers are suggesting that bread and cereal products intended for the elderly should be fortified with folic acid to reduce homocysteine levels and thus the risk of bone fracture, we at the World’s Healthiest Foods have a simpler suggestion: Eat a minimum of 5 servings of folic acid-rich foods each day! Why settle just for folic acid when these vegetables provide not only folic acid, but hundreds of other nutrients that promote your health and well-being in dozens of ways. Plus, with the quick, easy and delicious recipes George Mateljan has created for you, getting your folic acid can be an infinitely more interesting and pleasant experience than eating a piece of fortified bread! (June 3, 2004)

Cell Production

Cells with very short life spans (like skin cells, intestinal cells, and most cells that line the body's exposed surfaces or cavities) are highly dependent on folic acid for their creation. For this reason, folic acid deficiency has repeatedly been linked to problems in these types of tissue.

In the mouth, these problems include gingivitis, cleft palate, and periodontal disease. In the skin, the most common folate deficiency-related condition is seborrheic dermatitis. Vitiligo (loss of skin pigment) can also be related to folic acid deficiency. Cancers of the esophagus and lung, uterus and cervix, and intestine (especially the colon) have been repeatedly linked to folate deficiency.

Nervous system support

Prevention of neural tube defects in newborn infants is only one of the nervous system-related functions of folic acid. Deficiency of folate has been linked to a wide variety of nervous system problems, including general mental fatigue, non-senile dementia, depression, restless leg syndrome, nervous system problems in the hands and feet, irritability, forgetfulness, confusion, and insomnia. The link between folate and many of these conditions may involve the role of folate in maintaining proper balance in nervous system's message-carrying molecules. These molecules, called neurotransmitters, often depend upon folic acid for their synthesis.

Deficiency Symptoms

What are deficiency symptoms for folate?

Because of its link with the nervous system, folate deficiency can be associated with irritability, mental fatigue, forgetfulness, confusion, depression, and insomnia. The connections between folate, circulation, and red blood cell status make folate deficiency a possible cause of general or muscular fatigue. The role of folate in protecting the lining of body cavities means that folate deficiency can also result in intestinal tract symptoms (like diarrhea) or mouth-related symptoms like gingivitis or periodontal disease.

Toxicity Symptoms

What are toxicity symptoms for folate?

At very high doses greater than 1,000-2,000 micrograms, folate intake can trigger the same kinds of nervous system-related symptoms that it is ordinarily used to prevent. These symptoms include insomnia, malaise, irritability, and intestinal dysfunction. Primarily for these reasons, the Institute of Medicine at the National Academy of Sciences set a tolerable upper limit (UL) in 1998 of 1,000 mcg for men and women 19 years and older. This UL was only designed to apply to "synthetic folate" defined as the forms obtained from supplements and/or fortified foods.

Impact of Cooking, Storage and Processing

How do cooking, storage, or processing affect folate?

Folate contained in animal products (like beef liver) appears to be relatively stable to cooking, unlike folate in plant products (like cabbage) which can lose up to 40% of their folate content from cooking. Processed grains and flours can lose up to 70% of their folate, and despite this processing loss, processed grains and flours are not required to be enriched with folate, even though they are legally required to be enriched with other B vitamins including B1, B2, and B3.

Factors that Affect Function

What factors might contribute to a deficiency of folate?

In addition to poor dietary intake of folate itself, deficient intake of other B vitamins can contribute to folate deficiency. These vitamins include B1, B2, and B3 which are all involved in folate recycling. Poor protein intake can cause deficiency of folate binding protein which is needed for optimal absorption of folate from the intestine, and can also be related to an insufficient supply of glycine and serine, the amino acids that directly participate in metabolic recycling of folate. Excessive intake of alcohol, smoking, and heavy coffee drinking can also contribute to folate deficiency.

Drug-Nutrient Interactions

What medications affect folate?

Medications that can help deplete the body's supply of folate include: anticancer drugs like methotrexate; cholesterol-lowering drugs like cholestyramine; anti-inflammatory drugs like sulfasalazine; biguanide drugs like buformin, phenformin, or metformin used in the treatment of diabetes; birth control pills (oral contraceptives); potassium-sparing diuretics like triamterene; and antibiotics like trimethoprim or pyrimethamine.

Nutrient Interactions

How do other nutrients interact with folate?

Vitamins B1, B2, and B3 must be present in adequate amounts to enable folic acid to undergo metabolic recycling in the body. Excessive amounts of folic acid, however, can hide a vitamin B12 deficiency, by masking blood-related symptoms.

Health Conditions

What health conditions require special emphasis on folate?

Folate may play a role in the prevention and/or treatment of the following health conditions:
  • Alcoholism
  • Anemias (especially macrocytic anemia)
  • Atherosclerosis
  • Cervical dysplasia
  • Cervical tumors
  • Cleft palate or cleft lip
  • Crohn's disease
  • Depression
  • Diarrhea
  • Gingivitis
  • Glossitis
  • Glycogen storage disease type I
  • Hyperhomocysteinemia
  • Inflammatory bowel disease
  • Insomnia
  • Myelopathy
  • Neural tube defects
  • Non-senile dementia
  • Ovarian tumors
  • Periodontal disease
  • Restless leg syndrome
  • Schizophrenia
  • Seborrheic dermatitis
  • Tropical sprue
  • Uterine tumors

Form in Dietary Supplements

What forms of folate are found in dietary supplements?

Folic acid is normally found in its simple form (also called pteroylmonoglutamic acid) in dietary supplements. Folinic acid (also called 5-formyltetrahydrofolate) is also available, and can help by-pass certain biochemical steps that occur in the body once folate has been absorbed from the intestine.

Food Sources

Introduction to Nutrient Rating System Chart

The following chart shows the foods which are either excellent, very good or good sources of this nutrient. Next to each food name you will find the following information: the serving size of the food; the number of calories in one serving; DV% (percent daily value) of the nutrient contained in one serving (similar to other information presented in the website, this DV is calculated for 25-50 year old healthy woman); the nutrient density rating; and the food's World's Healthiest Foods Rating. Underneath the chart is a table that summarizes how the ratings were devised. For more detailed information on our Nutrient Rating System, please click here.

 

Foods Ranked as quality sources of:
folate
Food Serving
Size
Cals Amount
(mcg)
DV
(%)
Nutrient
Density
World's
Healthiest
Foods Rating
Lettuce, Romaine 2 cup 15.7 151.98 38.0 43.6 excellent
Spinach (boiled, with salt) 1 cup 41.4 262.44 65.6 28.5 excellent
Asparagus, Boiled 1 cup 43.2 262.80 65.7 27.4 excellent
Greens, Turnip, Cooked 1 cup 28.8 170.50 42.6 26.6 excellent
Greens, Mustard, Boiled 1 cup 21.0 102.76 25.7 22.0 excellent
Liver, Calf 4 oz-wt 187.1 860.70 215.2 20.7 excellent
Parsley, Fresh 1 oz-wt 10.2 43.09 10.8 19.0 excellent
Collard Greens, Boiled, Drained 1 cup 49.4 176.70 44.2 16.1 excellent
Broccoli (pieces, steamed) 1 cup 43.7 93.91 23.5 9.7 excellent
Cauliflower (boiled, drained) 1 cup 28.5 54.56 13.6 8.6 excellent
Beets, Boiled 1 cup 74.8 136.00 34.0 8.2 excellent
Celery, Raw 1 cup 19.2 33.60 8.4 7.9 very good
Peppermint Leaves, Fresh 1 oz-wt 19.9 32.32 8.1 7.3 very good
Lentils, Boiled 1 cup 229.7 357.98 89.5 7.0 excellent
Brussels Sprouts, Boiled 1 cup 60.8 93.60 23.4 6.9 very good
Beans, Pinto, Cooked 1 cup 234.3 294.12 73.5 5.6 very good
Beans, Black, Boiled 1 cup 227.0 255.94 64.0 5.1 very good
Beans, Garbanzo, Cooked 1 cup 269.0 282.08 70.5 4.7 very good
Beans, Kidney, Cooked 1 cup 224.8 229.39 57.3 4.6 very good
Squash, Summer, All Varieties 1 cup 36.0 36.18 9.0 4.5 very good
Cucumber, Raw 1 cup 13.5 13.52 3.4 4.5 good
Beans, Navy, Cooked 1 cup 258.4 254.62 63.7 4.4 very good
Papaya 1 each 118.6 115.52 28.9 4.4 very good
Green Snap/String Beans, Boiled 1 cup 43.8 41.63 10.4 4.3 very good
Cabbage (shredded, boiled) 1 cup 33.0 30.00 7.5 4.1 very good
Fennel Bulb, Sliced, Raw 1 cup 27.0 23.50 5.9 3.9 very good
Red Bell Peppers (sliced, raw) 1 cup 24.8 20.24 5.1 3.7 very good
Leeks, Boiled 0.50 cup 16.1 12.64 3.2 3.5 good
Green Peas-Boiled 1 cup 134.4 101.28 25.3 3.4 very good
Beans, Lima, Cooked 1 cup 216.2 156.23 39.1 3.3 good
Squash, Winter, All Varieties 1 cup 80.0 57.40 14.3 3.2 good
Tomato, Red, Raw, Ripe 1 cup 37.8 27.00 6.8 3.2 good
Oranges 1 each 61.6 39.69 9.9 2.9 good
Mushrooms, Crimini, Raw 5 oz-wt 31.2 19.85 5.0 2.9 good
Strawberries, Fresh 1 cup 43.2 25.49 6.4 2.7 good
Seeds, Flax 0.25 cup 190.6 107.72 26.9 2.5 good
Split Peas, Boiled 1 cup 231.3 127.20 31.8 2.5 good
Raspberries, Fresh 1 cup 60.3 31.98 8.0 2.4 good
Eggplant, Boiled 1 cup 27.7 14.26 3.6 2.3 good
Onions, Raw 1 cup 60.8 30.40 7.6 2.3 good
Cantaloupe 1 cup 56.0 27.20 6.8 2.2 good
Kale, Fresh, Boiled 1 cup 36.4 17.29 4.3 2.1 good
Chard, Boiled 1 cup 35.0 15.05 3.8 1.9 good
Corn, Yellow, Boiled 1 cup 177.1 76.10 19.0 1.9 good
Peanuts, Raw 0.25 cup 207.0 87.53 21.9 1.9 good
Sunflower Seeds, Dried 0.25 cup 205.2 81.86 20.5 1.8 good
Avocado, All Varieties 1 cup 235.1 90.37 22.6 1.7 good
Carrots, Raw 1 cup 52.5 17.08 4.3 1.5 good
World's Healthiest
Foods Rating
Rule
excellent DV>=75% OR Density>=7.6 AND DV>=10%
very good DV>=50% OR Density>=3.4 AND DV>=5%
good DV>=25% OR Density>=1.5 AND DV>=2.5%

Public Health Recommendations

What are current public health recommendations for folate?

The Recommended Dietary Allowances for folic acid, set in 1998 by the Institute of Medicine at the National Academy of Sciences, are as follows:

  • 0-6 months: 65 micrograms
  • 6-12 months: 80 micrograms
  • 1-3 years: 150 micrograms
  • 4-8 years: 200 micrograms
  • Males 9-13 years: 300 micrograms
  • Males 14 years and older: 400 micrograms
  • Females 9-13 years: 300 micrograms
  • Females 14 years and older: 400 micrograms
  • Pregnant females of any age: 600 micrograms
  • Lactating females of any age: 500 micrograms

References

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  • Ristow KA, Gregory JF, Damron BL. Thermal processing effects on folacin bioavailability in liquid model food systems, liver and cabbage. J Agr Food Chem 1982;30(5):801-806.
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  • Steinberg SE. Mechanisms of folate homeostasis. Am J Physiol 1984;246:G319-G324.
  • Terry P, Jain M, Miller AB et al. Dietary intake of folic acid and colorectal cancer risk in a cohort of women. Int J Cancer 2002 Feb 20;97(6):864-7.
  • Ubbink JB, Vermaak WJ, van der Merwe A, Becker PJ. Vitamin B-12, vitamin B-6, and folate nutritional status in men with hyperhomocysteinemia. Am J Clin Nutr 1993 Jan;57(1):47-53.
  • van Meurs JB, Dhonukshe-Rutten RA, Pluijm SM, van der Klift M, de Jonge R, Lindemans J, de Groot LC, Hofman A, Witteman JC, van Leeuwen JP, Breteler MM, Lips P, Pols HA, Uitterlinden AG. Homocysteine levels and the risk of osteoporotic fracture. N Engl J Med. 2004 May 13;350(20):2033-41.
  • Zimmerman MB, Shane B. Supplemental folic acid. Am J Clin Nutr 1993;58:127-128.

This page was updated on: 2004-11-21 11:15:23
© 2002 The George Mateljan Foundation