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 Folic Acid

Overview

Folic Acid is a B vitamin which is found naturally in leafy vegetables, citrus fruits, beans, and whole grains. Folate and folic acid are interchangeable terms; folic acid is the synthetic form of folate.

Scientists are in general agreement that folic acid reduces the risk of neural tube defects, which are serious birth defects, including spina bifida and anencephaly. In 1992, the Food and Drug Administration (FDA) recommended fortifying the nation’s food supply with folic acid, a strategy that has worked well in the past with other beneficial substances including iodine (in salt), vitamin D (in milk), and thiamin (in flour and bread). Folic acid began being added to breads and other grain products in January of 1998.

The neural tube defects that folic acid can prevent, including spina bifida and anencephaly, are among the most serious and frequently occurring birth defects. Spina bifida occurs when the fetus’ spinal column does not close to protect the spinal cord; this closure should happen within the first few weeks of the pregnancy. Spina bifida causes neurological problems and sometimes, varying levels of mental retardation. Anencephaly is a condition in which the baby’s brain does not develop properly and most or all of the brain tissue is absent.  Anencephaly results in either stillbirth or death soon after delivery.

Scientists representing many public and private agencies and organizations, including the Food and Drug Administration, the Public Health Service, the Teratology Society, and the Spina Bifida Association of America recommend that women of childbearing age (15–45 years old) take folic acid as a part of their daily diet, not when they become pregnant which is often too late to prevent these birth defects.

A recent report by the National Center for Health Statistics examines the US incidences of spina bifida and anencepahlus over an 11-year period from 1991-2001 and shows significant decreases in the 2001 incidences of these birth defects as compared to the 1997 rates.

What is Folic Acid / Folate

Folic acid is a chemical that is essential to sustain human life and must be provided in adequate amounts through food or other dietary supplements. Folic acid is a B vitamin which scientists agree reduces the risk of neural tube defects, including spina bifida and anencephaly, by up to 70% when taken regularly by women of child bearing age. In order to be effective, folic acid must be taken during the first weeks of pregnancy when these neural tube defects occur.

Folate and folic acid are interchangeable terms. Folic acid is the synthetic form of folate, which is found naturally in some foods, including leafy vegetables, beans (legumes), citrus fruits, and whole grains.

Neural Tube Defects

According to the FDA (FDA February 29, 1996):

Neural tube defects (NTD), including spina bifida and anencephaly, are the most common disabling birth defects.

  • Approximately 2,500 infants are born each year in the U.S. with an NTD. About half of these cases are thought to be related to inadequate folate intake by the mother. Other NTDs have different causes that are not well understood.
  • Spina bifida is a condition in which the spinal cord is exposed. A majority of babies born with spina bifida grow to adulthood with varying degrees of disability, ranging to problems with bowel and bladder control, and paralysis. Many may require a series of operations and other treatments.
  • In anencephaly, infants die shortly after birth because most or all of the brain is absent.

Since NTDs develop very early in pregnancy (18-30 days after conception), often before a woman knows she is pregnant, it is essential that adequate intake of folic acid be maintained throughout the childbearing years.

Women who have had a prior NTD-affected pregnancy are at high risk of having a subsequent affected pregnancy. When these women are planning to become pregnant, they should consult their physicians for advice.

Spina Bifida

The FDA (FDA Consumer, May 1994) has stated:

Spina bifida is a defect of the spinal column. If the vertebrae (bones of the spinal column) surrounding the spinal cord do not close properly during the first 28 days after fertilization, the cord or spinal fluid bulge through, usually in the lower back.

While once all these children died, with proper medical treatment, about 85 to 90 percent of them now live to adulthood, according to the Spina Bifida Association of America. Depending on the severity of the condition, they have varying degrees of paralysis and incontinence.

There are two major forms of the condition. The mild form, spina bifida occulta ("hidden") is only a small gap in the spine, with a dimple in the skin covering it. There are usually no symptoms. Some Americans have spina bifida occulta and don't even know they have it, according to the National Information Center for Children and Youth with Disabilities.

The more disabling form is spina bifida aperta, which produces an noticeable sac on the infant's back. A small sac, called a meningocele, produces little or no muscle paralysis or incontinence once it is repaired.

But in 90 percent of all spina bifida cases, a portion of the undeveloped spinal cord itself protrudes through the spine and forms a sac protruding on the baby's back. Any portion of the spinal cord outside the vertebrae is undeveloped or damaged, causing paralysis and incontinence. This is called a myelocele (or meningomyelocele), and it is what most people refer to as spina bifida.

The location of the sac determines how severely disabled the child will be. In general, the higher it is on the spinal column, the more paralysis there is.

Doctors must repair the opening of the spine shortly after birth or the child will die. Other major surgeries often follow in the child's first years. About 85 percent of children with spina bifida develop hydrocephalus, an accumulation of cerebrospinal fluid surrounding the brain. This fluid must be drained to the abdomen or bloodstream with a surgically implanted tube.

Some children with spina bifida develop foot and knee deformities caused by an interruption of spinal nerve circuits. Many patients require leg braces, crutches, and other devices to help them walk. They may have learning disabilities, and about 30 percent of children have slight to severe mental retardation, especially if they have chronic hydrocephalus. Chronic bladder infections and kidney problems require lifelong medical attention.

Despite their need for medical attention, children with spina bifida can learn to care for many of their own needs. They often learn to catheterize themselves, for instance, so they can attend regular schools. With proper medical care, a person with spina bifida can live a long and productive life.

Testing for Neural Tube Defects

According to the FDA (FDA Consumer, May 1994):

A number of tests are available to diagnose neural tube defects before a baby is born.

One such test, the maternal serum alpha-fetoprotein (AFP) test, is a blood test for the mother at 16 to 18 weeks into the pregnancy. It was approved by FDA in the early 1980s as a prenatal test for neural tube defects (a second approved use is as an aid for a certain kind of testicular cancer).

The test measures alpha-fetoprotein, a substance produced by the fetus and secreted into the amniotic fluid, eventually entering the mother's blood. As it grows, the baby produces increased amounts of AFP. The level of AFP in mother's blood peaks at about 30 to 32 weeks.

Abnormally high amounts of AFP may indicate a baby has a neural tube defect. But the test is not perfect.

Up to 20 percent of spina bifida cases do not produce high levels of AFP, so the test does not detect them. And when the test does indicate a high level of AFP, a neural tube defect is present only 10 percent of the time. Most commonly, the AFP level is high because the pregnancy is just further along than was thought.

If a woman has an elevated AFP test, her doctor will usually give her a second AFP test, followed by ultrasound. If still no explanation for a high AFP value can be found, the physician may perform amniocentesis. In this test, the doctor takes a sample of the amniotic fluid and measures it for AFP levels. The results of these tests together will identify a high percentage of spina bifida cases.

History

The FDA (FDA Consumer 1996, 1999 update) has stated:

Scientists first suggested a link between neural tube birth defects and diet in the 1950s. The incidence of these conditions has always been higher in low socioeconomic groups in which women may have poorer diets. Also, babies conceived in the winter and early spring are more likely to be born with spina bifida, perhaps because the mother's diet lacks fresh fruits and vegetables--which are good sources of folate--during the early weeks of pregnancy.

In 1991, British researchers found that 72 percent of women who had one pregnancy with a neural tube birth defect had a lower risk of having another child with this birth defect when they took prescription doses of folic acid before and during early pregnancy.

Another study looked at folic acid intake in Hungarian women. The evidence indicated that mothers who had never given birth to babies with neural tube defects and who took a multivitamin and mineral supplement with folic acid had less risk in subsequent pregnancies for having babies with neural tube defects than women given a placebo.

The FDA (FDA February 29, 1996) also stated:

The U.S. Public Health Service (PHS) recommended in September 1992 that all women of childbearing age consume 400 micrograms (ug) of folic acid daily to reduce their risk of having a pregnancy affected with spina bifida or other neural tube defects.

In keeping with the recommendations of PHS and the FDA Food Advisory Committee called to study these issues, the Food and Drug Administration is requiring that folic acid be added to specific flour, breads and other grains. These foods were chosen for fortification with folate because they are staple products for most of the U.S. population, and because they have a long history of being successful vehicles for improving nutrition to reduce the risk of classic nutrient deficiency diseases.

These fortified foods include most enriched breads, flours, corn meals, rice, noodles, macaroni and other grain products.

Food fortification has been introduced effectively in the past. According to the FDA (FDA February 29, 1996), "Addition of iodine to salt was one of the earliest successful fortification programs. Iodine fortification was initiated in the U.S. in 1924 to prevent goiter, cretinism and other symptoms of severe iodine deficiency. In the early 1930s, vitamin D was first added to cow's milk to aid in absorption of calcium and phosphorus, preventing development of rickets".

One concern in fortifying foods with folic acid is that among the elderly, high levels of folic acid can complicate the prompt diagnosis of vitamin B12 deficiency (FDA February 29, 1996).  In addition, there may be other adverse effects from high folic acid intakes and therefore, care should be taken to keep total folate consumption under 1 mg per day, except under the supervision of a physician.  Along with this fortification, the PHS suggests two other ways to ensure the proper level of folic acid: improved dietary habits and daily use of folic acid supplements by women throughout their childbearing years (FDA February 29, 1996).  The FDA rule is designed to keep total folic acid intake under the 1 mg level.

FDA regulation

Studies have shown that folic acid, when consumed daily before pregnancy and during the early months of pregnancy, can prevent up to 70 percent of disabling or fatal birth defects of the brain and spine known as neural tube defects.  Therefore, the FDA now requires that Folic Acid be added to specific grain products.

Under the terms of the new FDA rule (FDA February 29, 1996):

  • Fortification levels will range from 0.43 milligrams to 1.4 mg per pound of product.
  • Fortification of grain products at these levels will allow the daily intake from all sources to remain below the recommended upper limit of 1 mg per day.
  • The amount of folic acid that will be consumed through foods fortified at these levels is considered safe for all population (age/gender) groups.
  • Manufacturers will be allowed to make claims on the labels that the fortified products contain folic acid and that adequate intake of the nutrient may reduce the risk of neural tube defects.

Evidence that these public health actions have been effective is presented in the 1999 National Health and Nutrition Examination Survey which reports a significant increase in serum folic acid concentrations in women of reproductive age as compared with survey values obtained for 1988-1994.

Who should take Folic Acid

According to the March of Dimes http://www.marchofdimes.com/pregnancy/folicacid.html, folic acid should be taken by all women of reproductive age (from about 15-45 years old), who are capable of becoming pregnant, who are planning pregnancy, or are in early pregnancy.

Richard B. Johnston, Jr., M.D., medical director of the March of Dimes (MOD, 2002) has stated "In order to be effective in preventing birth defects, folic acid must be consumed before conception and during the first four weeks of pregnancy. Since nearly half of all pregnancies in this country are unplanned, all women capable of having a baby should be consuming folic acid every day."

The Teratology Society (Teratology Society 1997) recommends that "1) women in the childbearing age group take a daily vitamin supplement containing 0.4 mg of folic acid; 2) fortification of enriched cereal grain products be carried out to a level that will provide 0.4 mg of folic acid each day to at least 95% of women in the reproductive age group; and 3) research designed to understand the mechanism by which folic acid or metabolically related chemicals reduce the risk of birth defects be strongly encouraged".


Naturally occurring sources of Folic Acid

The March of Dimes Birth Defects Foundation warns women not to rely on these foods for enough folic acid to prevent serious birth defects in their future babies (March of Dimes 1997).

The following are natural sources for varying amounts of folate which were obtained from the FDA (FDA Consumer, May 1994):

Food Sources of Folic Acid

-- Food Type Micrograms (per 100 grams of food, or 3.5 oz)
-- Dark-green leafy vegetables
-- Other vegetables
-- Fruits (particularly citrus)
-- Beans (legumes)
-- Whole grains
-- Breakfast cereals
120-160
40-100
50-100
50-300
60-120
100-400

The following FDA table (FDA Consumer 1996, updated 1999) lists folic acid levels of specific foods:

Amount of Folic Acid in different foods

-- Food Serving
Size
Amount (micrograms)
Daily value, % *
-- Chicken liver
-- Breakfast cereals
-- Braised beef liver
-- Lentils
-- Chickpeas
-- Asparagus
-- Spinach
-- Black Beans
-- Burritos with beans
-- Kidney beans
-- Baked beans with pork
-- Lima beans
-- Tomato juice
-- Brussels sproutes
-- Orange
-- Broccoli, cooked
-- Fast-food french fries
-- Wheat germ
-- Fortified white bread
3 1/2 oz
1/2 to 1 1/2 cup
3 1/2 oz
cooked 1/2 cup
1/2 cup
1/2 cup
cooked 1/2 cup
1/2 cup
2
1/2 cup
1 cup
1/2 cup
1 cup
1/2 cup
medium
1/2 cup
large order
1 tbsp
1 slice
770
100-400
217
180
141
132
131
128
118
115
92
78
48
47
47
39
38
38
38
193
25-100
54
45
35
33
33
32
30
29
23
20
12
12
12
10
10
10
10

* based on Daily value for folate of 400 micrograms

More Information

For further information on folic acid and neural tube defects see: http://www.aap.org/policy/re9834.htm


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