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
- Help prevent dementias including Alzheimer’s disease
What events can indicate a need for more high-folate foods?
- Mental fatigue, forgetfulness, or confusion
- General or muscular fatigue
- Gingivitis or periodontal disease
For serving size for specific foods see the Nutrient Rating Chart.
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.
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!
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. It’s been fascinating to see a link discovered by researchers between mothers who follow a Mediterranean-style diet and lowered risk of spina bifida (SB) in their infants. (SB is a set of conditions that include neural tube defects.) The ability of a Mediterranean-type diet to supply rich amounts of folic acid and other nervous system supportive nutrients is believed to be the reason that a Mediterranean-type diet in the lifestyle of the mother works so well in decreasing her infant’s SB risk.
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.
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.
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 B12deficiency, by masking blood-related symptoms.
What health conditions require special emphasis on folate?
Folate may play a role in the prevention and/or treatment of the following health conditions:
- Anemias (especially macrocytic anemia)
- Cervical dysplasia
- Cervical tumors
- Cleft palate or cleft lip
- Crohn’s disease
- Glycogen storage disease type I
- Inflammatory bowel disease
- Neural tube defects
- Non-senile dementia
- Ovarian tumors
- Periodontal disease
- Restless leg syndrome
- Seborrheic dermatitis
- Tropical sprue
- Uterine tumors
What foods provide folate?
Very good sources include summer squash, black beans, navy beans, kidney beans, pinto beans,garbanzo beans, papaya, strawberries, green beans sea vegetables, cabbage, bell peppers, Brussels sprouts, leeks, fennel, tomatoes, and green peas.
Nutrient Rating Chart
Introduction to Nutrient Rating System Chart
In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the World’s Healthiest Foods that are either an excellent, very good, or good source of folate. Next to each food name, you’ll find the serving size we used to calculate the food’s nutrient composition, the calories contained in the serving, the amount of folate contained in one serving size of the food, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration’s “Reference Values for Nutrition Labeling.” Read more background information and details of our rating system.
|World’s Healthiest Foods ranked as quality sources of
|Turnip Greens||1 cup||28.8||169.92||42.48||26.5||excellent|
|Romaine Lettuce||2 cups||16.0||127.84||31.96||36.0||excellent|
|Bok Choy||1 cup||20.4||69.70||17.43||15.4||excellent|
|Pinto Beans||1 cup||244.5||294.12||73.53||5.4||very good|
|Garbanzo Beans||1 cup||269.0||282.08||70.52||4.7||very good|
|Black Beans||1 cup||227.0||256.28||64.07||5.1||very good|
|Navy Beans||1 cup||254.8||254.80||63.70||4.5||very good|
|Kidney Beans||1 cup||224.8||230.10||57.52||4.6||very good|
|Papaya||1 medium||118.7||102.12||25.53||3.9||very good|
|Brussels Sprouts||1 cup||56.2||93.60||23.40||7.5||very good|
|Green Peas||1 cup||115.7||86.78||21.70||3.4||very good|
|Bell Peppers||1 cup||28.5||42.32||10.58||6.7||very good|
|Green Beans||1 cup||43.8||41.25||10.31||4.2||very good|
|Celery||1 cup||16.2||36.36||9.09||10.1||very good|
|Cabbage||1 cup||43.5||36.00||9.00||3.7||very good|
|Summer Squash||1 cup||36.0||36.00||9.00||4.5||very good|
|Strawberries||1 cup||46.1||34.56||8.64||3.4||very good|
|Tomatoes||1 cup||32.4||27.00||6.75||3.8||very good|
|Leeks||1 cup||32.2||24.96||6.24||3.5||very good|
|Fennel||1 cup||27.0||23.49||5.87||3.9||very good|
|Lima Beans||1 cup||216.2||156.04||39.01||3.2||good|
|Dried Peas||1 cup||231.3||127.40||31.85||2.5||good|
|Sunflower Seeds||0.25 cup||204.4||79.45||19.86||1.7||good|
|Winter Squash||1 cup||75.8||41.00||10.25||2.4||good|
|Collard Greens||1 cup||62.7||30.40||7.60||2.2||good|
|Beet Greens||1 cup||38.9||20.16||5.04||2.3||good|
|Mushrooms, Crimini||1 cup||15.8||18.00||4.50||5.1||good|
|Kiwifruit||1 2 inches||42.1||17.25||4.31||1.8||good|
|Swiss Chard||1 cup||35.0||15.75||3.94||2.0||good|
|Mushrooms, Shiitake||0.50 cup||40.6||15.22||3.81||1.7||good|
|Mustard Greens||1 cup||36.4||12.60||3.15||1.6||good|
|Lemons and Limes||0.25 cup||13.4||12.20||3.05||4.1||good|
Density>=7.6 AND DRI/DV>=10%
|very good||DRI/DV>=50% OR
Density>=3.4 AND DRI/DV>=5%
Density>=1.5 AND DRI/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
In 1998, the Institute of Medicine at the National Academy of Sciences set a tolerable upper limit (UL) 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. For more details on this, see the Toxicity Symptoms section above.
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