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
• Help prevent dementias including Alzheimer’s disease

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.

For serving size for specific foods see the Nutrient Rating Chart.

Description Function Deficiency Symptoms Toxicity Symptoms Cooking, storage and processing Factors that affect function

Nutrient interaction Health conditions Food Sources Nutrient Rating Chart Public Health Recommendations References

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.

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. 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.

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.

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 B12deficiency, 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

Food Sources

What foods provide folate?

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

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.

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.

References

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