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Folic acid (folate, vitamin B9) |
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| Folate and folic acid are forms of a water-soluble B vitamin. Folate occurs naturally in food. Folic acid is a synthetic folate form which is used for food fortification and nutritional supplements. It is not one of the principal naturally occurring forms of folate, used in the collective sense. Folate and folic acid are the preferred synonyms for pteroylglutamate and pteroylglutamic acid, respectively. Folic
acid or pteroylglutamic acid (PGA) is comprised of para-aminobenzoic acid linked at one end to a pteridine ring and at the other end to glutamic acid. The pteridine-para-aminobenzoic acid portion of the molecule is called the pteroyl group. Folic acid has yellowish-orange crystals, extremely thin platelets (elongated at two ends) from hot water, no melt point known, and it is not very soluble.
Folic acid plays an essential role in human growth and development, in particular cell division and DNA synthesis. Folic acid is essential for cell duplication because DNA can not be produced without sufficient folic acid because it is essential to make the critical base pairs needed by DNA molecules. The demand for folic acid increases when human cell growth is very active, such as in pregnancy, during breastfeeding, growth and some cancers e.g., leukaemias. Folates are also involved in reactions leading to de novo purine nucleotide synthesis, interconversion of serine and glycine, generation and utilization of formate, the metabolism of L-histidine to L-glutamic acid, the metabolism of dimethylglycine to sarcosine and the metabolism of sarcosine to glycine.
Folic acid is crucial for proper brain function and plays an important role in mental and emotional health. Folic acid also works closely together with vitamin B12 to regulate the formation of red blood cells and to help iron function properly in the body. Folic acid is necessary for the proper differentiation and growth of cells and for the development of the fetus. Folic acid increases the appetite and stimulates the production of stomach acid for digestion and it aids in maintaining a healthy liver. Folic acid helps protect the chromosomes, is needed for the utilization of sugar and amino acids, promotes healthier skin and helps protect against intestinal parasites and food poisoning. Folic acid helps to eliminate homocysteine, a blood toxin known to affect heart muscle and influences cholesterol to deposit in heart muscle. Additionally, folic acid may play an important role in prevention of certain cancers: lung, colon, and cervical.
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Folic acid (folate, vitamin B9) functions, uses, and health benefits |
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| Folic acid plays an essential role in human growth and development, in particular cell division and DNA synthesis. Folic acid is involved in every bodily function that requires cell division. Folic acid works along with vitamin B12 and vitamin C to help the body digest and utilize proteins and to synthesize new proteins when they are needed. Folic acid is important for any stage of human life which involves growth such as pregnancy, lactation and early growth because of the role the folate plays in DNA, RNA and protein
production. Folic acid is indicated for the prevention of some birth defects and appears to confer significant protection against cardiovascular disease and some forms of cancer. Synthetic folic acid supplements may be used in the treatment of disorders associated with folic acid deficiency and may also be part of the recommended treatment for certain menstrual problems and leg ulcers. Folic acid also helps with tissue growth and cell function. In addition, it helps to increase appetite when needed and stimulates the formation of digestive acids.
Folic acid and pregnancy - Pregnant women have an increased need for folic acid, both for themselves and their child. Folic acid also is crucial to support the rapid growth of the placenta and fetus. Taken as part of a B-complex vitamin that contains biotin and vitamin B12, folic acid can strengthen the reproductive system in women having trouble conceiving. Without adequate amounts of folic acid, cell division could be impaired, possibly leading to poor growth in the fetus or placenta. Adequate intake of folic acid is vital for the prevention of several types of birth defects, particularly neural tube defects. Women who have a family history of neural tube defects or who have had a baby with a neural tube defect should take 5mg of folate daily and other women should take 0.5mg of folate daily.
Folic acid and heart disease - Folic acid appears to regulate the body's production and use of homocysteine. High levels of a substance called homocysteine in the blood is considered to be a risk factor for heart disease. An elevated blood level of the amino acid homocysteine has been identified as a risk factor for some of these diseases. People who are at high risk of strokes and heart disease may greatly benefit by taking folic acid supplements. High levels of homocysteine have also been found to contribute to problems with osteoporosis. Folic acid, together with vitamins B6 and B12, helps break down homocysteine, and may help reverse the problems associated with elevated levels. Homocysteine levels can be reduced by taking folate (the general recommendation is at least 400 micrograms [mcg] per day, but some studies suggest that this daily amount must be at least 650 to 800 mcg.)
Folic acid and cancer - Folate status is associated with colorectal, lung, esophageal, brain, cervical and breast cancers. Folate is involved in the synthesis, repair, and functioning of DNA, our genetic map, and a deficiency of folate may result in damage to DNA that may lead to cancer. Folate is important for cells and tissues that rapidly divide. Cancer cells divide rapidly, and drugs that interfere with folate metabolism are used to treat cancer. Folate is critical for the synthesis of the transmethylating agent S-adenosylmethione (SAMe). SAMe methylates certain bases in DNA leading to gene silencing. Gene unsilencing alters gene expression and can disrupt the integrity of the genome. DNA hypomethylation appears to be an early, and consistent event in carcinogenesis, including that of colorectal cancer.
Folic acid and depression - Because folic acid is often deficient in those who are depressed, a supplement may help. Vitamin B9 (folate) may be associated with depression more than any other nutrient, and may play a role in the high incidence of depression in the elderly. Folic acid also appears to reduce the high levels of homocysteine associated with some forms of depression. Taking folic acid as part of a B-complex vitamin supplement is often recommended to combat depression.
Folic acid and cervical dysplasia - Folate deficiency appears to be linked to cervical dysplasia. Experts recommend getting adequate amounts of folate in the diet for all wome, which may be particularly important for those with risk factors for cervical dysplasia such as an abnormal pap smear or genital warts. Daily consumption of 1,000 mcg of folic acid for three or more months has resulted in improved cervical cells upon repeat Pap smears.
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Folic acid (folate, vitamin B9) dosage, intake, recommended daily allowance (RDA) |
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| The principal form of supplementary folate is folic acid. Folate triglutamate (pteroyltriglutamate) is also available. Folic acid is available in single ingredient and in combination products. A typical daily dose is 400 micrograms. Unit doses of one milligram or greater require a prescription. The best way to get enough folic acid is to take a multivitamin with 400 micrograms of folic acid in it and eat a healthy diet. The recommended dietary allowances (RDA) for folate is 400 mcg per day for adults, 600 mcg per day for pregnant women, and 500 mcg for nursing women. Medicinal dosages of up to 1,000-2,000 mcg per day may be prescribed. Women with a history of neural tube sefects need a higher daily allowance of folic acid, 4,000 micrograms. Because of the difference in absorption efficiency between natural food folate and folic acid, the concept of dietary folate equivalents (DFEs) has been introduced. Folic acid taken on an empty stomach is twice as available as food folate. Folic acid taken with food is 1.7 times as available as food folate. For example, 400 micrograms of folic acid taken on an empty stomach is equivalent to 470 micrograms of folic acid taken with food and is equivalent to 800 micrograms of food folate. Folic acid supplementation should always include vitamin B12 supplementation (400 to 1000 mcg daily) because folic acid can mask an underlying vitamin B12 deficiency, which can cause permanent damage to the nervous system. |
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Sources of folic acid (folate, vitamin B9) |
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| Folic acid found in foods is called folate. Natural folates are found in dark green leafy vegetables (spinach, kale, mustard greens, turnip greens, escarole, chard, arugula, beet greens, bok choy, dandelion green, mache, radicchio, rapini or broccoli de rabe, Swiss chard), oranges, lentils, pinto beans, garbanzo beans, asparagus, orange juice, broccoli, cauliflower, liver and brewer's yeast. Good food sources of folic acid include asparagus, beets, broccoli, avocados, Brussels sprouts, beans, dried, chickpeas, soybeans, lentils, oranges, peas, fresh, turkey, cabbage, savoy, bok choy, and spinach. Beans, leafy green vegetables, citrus fruits, beets, wheat germ, and meat are good sources of folic acid. Leafy greens such as spinach and turnip greens, dry beans and peas, fortified cereals and grain products, and some fruits and vegetables are rich food sources of folate. |
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Folic acid (folate, vitamin B9) deficiency |
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| Folic acid deficiency is one of the most common nutritional deficiencies and has been observed in alcoholics, pregnant women, people living in institutions e.g. nursing homes, people with absorption problems such as ulcerative colitis and people taking certain medications e.g., methotrexate. Folic acid deficiency during pregnancy increases the risk for neural tube defects including cleft palate, spina bifida, and brain damage. The requirement for folic acid increases considerably during pregnancy. Deficiencies of folic acid during pregnancy are associated with low birth weight and an increased incidence of neural tube defects in infants. Folate deficient women who become pregnant are at greater risk of giving birth to low birth weight, premature, and/or infants with neural tube defects. Signs of folic acid deficiency are often subtle. In most cases a folic acid deficiency occurs without any symptoms. In severe cases of folic acid deficiency signs and symptoms such as macrocytic anaemia, weakness, tiredness, irritability, forgetfulness, difficulty breathing, anorexia, diarrhoea, weight loss, headache, palpitations and inflammation of the tongue may occur. Folic acid deficiency causes mood disorders and low levels may play a role in depression, possibly due to a reduction in neurotransmitter levels. People with ulcerative colitis and Crohn's disease (both inflammatory bowel diseases) often have low levels of folic acid in their blood cells. Folate deficiency appears to be linked to cervical dysplasia. A deficiency of folic acid has also been associated with peripheral vascular disease and coronary artery disease even in people with normal homocysteine levels. |
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Folic acid (folate, vitamin B9) overdose, toxicity, side effects |
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| Toxicity from excessive folic acid intake does not normally occur, as folic acid is water soluble and regularly excreted by the body. According to the National Academy of Sciences, the daily intake of folic acid in adults should not exceed 1,000 mcg. Very high doses of this vitamin offer no additional therapeutic value. Very high doses (above 15,000 mcg) can cause stomach problems, sleep problems, skin reactions, and seizures. Further, high doses of folic acid are known to reduce or interfere with the effectiveness of methotrexate (an anticancer drug used in chemotherapy). Zinc, estrogen, anticonvulsant drugs, barbiturates, and sulfasalazine may not be absorbed as effectively when combined with folic acid. |
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