Back to Main  Page

Folic Acid (Vitamin B9)

Recommended Daily Allowance

America Australia UK
Men: 200 mcg 
Women: 180 mcg		 Men :200 mcg 
Women: 200 mcg		 Men: 200 mcg 
Women: 200 mcg

Uses and Facts

Dietary supplement to promote normal growth, development and good health. Treatment for anemias due to folic-acid deficiency occurring from alcoholism, liver disease, hemolytic anemia, sprue, infants on artificial formula, pregnancy, breast-feeding and use of oral-contraceptives.

Folic acid, which is also known as folate and folacin, is a family of bright yellow, water soluble compounds. Folic acid takes its name from the Latin word for foliage as high concentrations are found in leafy green vegetables. Folic acid is the most stable form of the vitamin and is usually used in fortified foods and supplements.

GENETIC MATERIAL

Folic acid is essential for the synthesis of DNA and RNA, the genetic material of cells. It plays a vital role in the growth and reproduction of all body cells, maintaining the genetic code, regulating cell division and transferring inherited characteristics from one cell to another.

METABOLISM

Folic acid is essential for protein metabolism.

BLOOD

The formation of healthy red and white blood cells requires folic acid.

BRAIN AND NERVOUS SYSTEM

Folic acid is involved in the production of neurotransmitters, including serotonin and dopamine, that regulate brain functions such as mood, sleep and appetite. Folic acid is essential for the development of the brain, spinal cord and skeleton in the fetus.

Absorption

Folic acid is absorbed from the small intestine and some is stored in the liver and other tissues. The amount stored may last for about four months before symptoms of deficiency develop. Some forms of folate are broken down in the intestine before absorption. The amount of folic acid absorbed from food depends on the source but the average is 50 per cent.

Deficiency

Folic acid deficiency is the most common nutritional deficiency in the world. Diets low in vegetables, frequent alcohol and prescription drug use and the sensitivity of folic acid to light and heat contribute to this widespread deficiency.

The elderly, alcoholics, psychiatric patients, epileptics and women taking the pill may be at greatest risk of folic acid deficiency. Prolonged stress, viral infections and chronic liver disease are also risk factors.

Folic acid deficiency affects the growth and repair of all the cells and tissues of the body. Cells that have the fastest rate of replacement are affected first.

BLOOD

Folic acid deficiency causes macrocytic anemia in which the red blood cells are fewer in number, larger in size and contain less oxygen carrying hemoglobin than normal. The symptoms of anemia are lethargy, apathy, breathlessness, poor body temperature regulation, pallor, forgetfulness, irritability and stomach disorders.

CARDIOVASCULAR DISEASE

Many studies have shown that low folic acid levels are linked to an increased risk of atherosclerosis and heart disease. These include the Framingham Heart Study, an ongoing analysis of the risk factors for heart disease which began almost 50 years ago and involves over 1000 men and women.

A recent Canadian study of the relationship between coronary heart disease and folic acid levels in 5000 men and women found that the risk of coronary heart disease increased as folic acid levels decreased. Those in the low intake group had a 69 per cent increased risk compared with those in the high intake group.

Folic acid may exert its protective effects on the heart by reducing the levels of homocysteine in the blood. Homocysteine is a product of protein breakdown which can damage the cells which line the arteries, thus leading to atherosclerosis and heart disease.

NERVOUS SYSTEM

Folic acid deficiency causes mood disorders and low levels may play a role in depression, possibly due to a reduction in neurotransmitter levels.

GASTROINTESTINAL SYSTEM

Symptoms of folic acid deficiency include loss of appetite, inflamed tongue, gastrointestinal problems and diarrhea. Folic acid deficiency can damage the lining of the gut and reduce absorption of other nutrients which can lead to malnutrition.

NEURAL TUBE DEFECTS

Folic acid deficiency is associated with birth defects. Pregnant women who are folic acid deficient risk having babies with neural tube defects such as anencephaly (failure of the brain to develop) and spina bifida (failure of the spinal column to close). These defects can occur before a woman is aware that she is pregnant so maintaining adequate folic acid levels is vital for any woman who might become pregnant. Folic acid may also improve the birth weight and nerve development in newborn babies (see page for more information).

CERVICAL DYSPLASIA

Low blood levels of folic acid have been linked to cervical dysplasia (precancerous changes in the cells lining the cervix). Research suggests that in some cases, although blood folic acid levels may be normal, levels in some tissues, including the cervix, may be low. Low folic acid levels may cause the genetic material of cells to become susceptible to damage by viruses while high levels may give protection from attack. Some studies suggest that oral contraceptives interfere with folic acid metabolism and that some abnormal Pap smears may, in fact, reflect folic acid deficiency rather than true dysplasia.

OTHER SYMPTOMS

Low folic acid may also contribute to rheumatoid arthritis and osteoporosis, constipation, cataracts, headaches and infertility.

Sources

If you regularly eat any of these foods--leafy greens, peas and beans, citrus fruits, whole grain bread and cereals--you're probably getting plenty. Folic acid reduces the chances of giving birth to a baby with neurological defects, so any woman planning a pregnancy should eat plenty of these foods or take a 400-mcg supplement.

The best sources are liver, brewer's yeast and dark green leafy vegetables such as spinach and kale. Dried beans, green vegetables, oranges, avocados and whole wheat products are also good sources.

Food processing such as boiling and heating can destroy folic acid. It can also be destroyed by being stored unprotected at room temperature for long periods.

Starting in 1998, commercial grain products in the USA will be enriched with between 0.43 mg and 1.4 mg of folic acid per pound of food. Breakfast cereals may contain up to a daily dose of folic acid.

Supplements

Folic acid is available as folic acid and also as folinic acid, the most active form of folic acid.

Pregnant women, the elderly and those with absorption difficulties may benefit from the use of supplements.

Interactions

Anticonvulsant drugs such as phenytoin and phenobarbital, aspirin, cholestyramine, chloramphenicol, estrogen, colchicine, antacids, methotrexate, anti tuberculosis drugs, trimethoprim, corticosteroid drugs, cigarettes and alcohol can raise folic acid requirements.

Folic acid requires vitamin B12, niacin and vitamin C to be converted to its biologically active form. High vitamin C intake can increase folic acid excretion.

Back to Main  Page