Folic Acid Resources

Researchers have found that 50-70% of NTDs can be prevented when women supplement their diet with folic acid, a water-soluble B vitamin. The Centers for Disease Control (CDC) recommends all women of childbearing age eat a diet high in folic acid or take a multivitamin with 0.4mg of folic acid each day, especially one month prior to conception through the first three months of pregnancy. This dosage is the amount found in most over-the-counter multivitamins. However, women who have had a previous NTD pregnancy are recommended to take an even higher dosage of folic acid prior to planning a pregnancy. They should increase the daily dose of folic acid from 0.4mg to 4.0mg (10x the recommended amount), one month prior to conception through the first three months of pregnancy. The 4.0mg of folic acid should only be obtained through a prescription from the doctor.

But even if you are not actively trying to get pregnant one should still take folic acid if you are engaging in any acts that may result in pregnancy. This is because the early spinal cord of the embryo begins as a flat region, which rolls into a tube (the neural tube) 28 days after the baby is conceived. When the neural tube does not close completely, an NTD (Neural Tube Defect) develops. NTDs develop before most women know they are even pregnant.

Its a good idea to increase your folic acid dosage even if you have not had history of a prior NTD. I am living proof that taking the recommended dosage does not prevent all NTDs. I was on the recommended dosage 3 months before trying to conceive and all through my pregnancy with Genesis. Had I been taking more folic acid she may have not been born with anencephaly. Though know that even with an increased intake of folic acid there is still a 1% chance you may have a child with a NTD. Another thing to keep in mind is that most people who have a child with a NTD have had no prior family history of NTDs.

How a woman can get enough folic acid?

There are two easy ways to be sure to get enough folic acid each day:

  1. Take a vitamin that has folic acid in it every day. 

    Most multivitamins sold in the United States have the amount of folic acid women need each day. Women can also choose to take a small pill (supplement) that has only folic acid in it each day. 

    Multivitamins and folic acid pills can be found at most local pharmacy, grocery, or discount stores. Check the label to be sure it contains 100% of the daily value (DV) of folic acid, which is 400 micrograms (mcg).
  2. Eat a bowl of breakfast cereal that has 100% of the daily value of folic acid every day. 

    Not every cereal has this amount. Check the label on the side of the box, and look for one that has “100%” next to folic acid.

AudioAudiocast: Folic Acid Now Audio/Video file 
Listen to an audiocast about folic acid.

What Foods Contain Folic Acid?
Approximately half of all pregnancies are unplanned, so the U.S. Food and Drug Administration has taken steps to fortify certain foods so that all women of childbearing age get a daily dose of folic acid. The following foods can help you obtain your recommended amount of folic acid:

  • Leafy green vegetables, such as large spinach salad
  • Citrus fruits, such as orange juice
  • Beans
  • Breads
  • Cereals
  • Rice
  • Pastas

Can You Overdose On Folic Acid?
Folic acid has no known toxic level. If you were to eat a bowl of fully fortified cereal (400 micrograms), take 400 micrograms (0.4 milligrams) folic acid supplement, and eat fortified foods and foods rich in folate, women of reproductive age would not have a problem with too much folic acid. Even in very high amounts folic acid is non-toxic. Nevertheless, it is recommended that women consume no more than 1,000 micrograms of synthetic folic acid a day. Large amounts of folic acid may hide the ability to quickly diagnose pernicious anemia, a rare vitamin B-12 deficiency. This condition primarily affects the elderly population and, in some cases, can lead to neurological damage. Today, Doctors can use a simple definitive test to check for a B-12 deficiency. Folic acid is water-soluble. Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. That means you need a continuous supply of the vitamin in your diet. Because of this, overdose is not likely. Anything your body cannot absorb gets excreted through your urine.

Findings from a survey conducted in 1998 to assess folic acid knowledge and practices among women of childbearing age in the United States indicate that of all women surveyed, only 13% knew that folic acid helps prevent birth defects, and only 7% knew that folic acid should be taken before pregnancy to prevent birth defects.

You should not take folic acid if you have any of these conditions. You may need a dose adjustment or special tests to safely use folic acid:
  • Kidney disease (or if you are on dialysis)
  • Hemolytic anemia
  • Pernicious anemia
  • Anemia that has not been diagnosed by a doctor and confirmed with laboratory testing
  • An infection
  • If you are an alcoholic
  • If you are allergic to folic acid

Who Is At Risk:
Sixty million women are of childbearing age in the United States; all those who are capable of becoming pregnant area at risk for having a NTD-affected pregnancy. It is not possible to predict which women will have a pregnancy affected by an NTD. 95% of NTDs occur in women with no personal or family history of NTDs. However, some risk factors are known:
  • An NTD-affected pregnancy increases a woman's chance to have another NTD-affected pregnancy by approximately twenty times
  • Maternal insulin-dependent diabetes
  • Anti-seizure medication use
  • Medically diagnosed obesity
  • High temperatures in early pregnancy (prolonged fevers and hot tub use, for example)
  • Race/ethnicity (NTDs are more common among white women than black women and more common among Hispanic woman than non-Hispanic women)
  • Lower socio-econimic status

Types Of Neural Tube Defects (NTDs)
There are two types of NTDs. The most common type are called the open NTDs. Open NTDs occur when the brain and/or spinal cord are exposed at birth through a defect in the skull or vertebrae (back bones). Examples of open NTDs are spina bifida (myelomeningocele), anencephaly, and encephalocele. Rarer types of NTDs are called closed NTDs. Closed NTDs occur when the spinal defect is covered by skin. Common examples of closed NTDs are lipomyelomeningocele, lipomeningocele, and tethered cord.

Lastly, spina bifida occulta (SBO) is potentially another form of an NTD in which there is a typically benign (or non-symptom-causing) bony change in one or more vertebrae, but not involving the nerves within the spinal column. The incidence of SBO is not well defined; however, it is more common than the NTDs described above. The cause and potential similarities, or, link to NTDs, has not been established.

Even More Folic Acid Resources:

A Connection Between Nitrous Oxide aka Laughing Gas and Neural Tube Defects

Folic Acid and B Vitamin Deficiencies
For the really health conscious among you (a contradiction in terms?) if you "must" do nitrous for a longer period be sure to take high doses of folic acid (is also depleted from your body as a result of functional B12 deficiency ) and vitamin B12. (No injury NOT guaranteed, but it might help)
Also, but less well known, the state of B12 deficiency caused by regular use of nitrous oxide produces hyperhomocysteinemia, an accumulation in the blood of the amino acid homocysteine. Hyperhomocysteinemia is a risk factor for vascular disease of all sorts. Furthermore, hyperhomocysteinemia, B12 deficiency and folic acid deficiency early in pregnancy all increase the risk of getting a child with a neural tube defect (spina bifida and anencephaly, childeren with no brains or open spinal cord). If you are a woman, planning to get pregnant or just "at risk of getting pregnant", nitrous is a bad idea.

B12 and Other Issues
There have been reports of immunological and reproductive disturbances in professionals who are chronically exposed to nitrous oxide. The immunological disturbances are documented by Peric et al (1991) _Anaethesia_ 46: 531-7. Apparently anaesthetic personnel had been complaining about weakness and recurrent infections and decreased peripheral blood leukocyte counts has been found. The operating rooms were found to be improperly ventilated, causing nitrous oxide and halothane (another anaesthetic) to remain in the air. Even after a 3-4 week holiday, some personnel has decreased B lymphocytes and increased red cell count, haemoglobin concentration and haematocrit and other disturbances. I don't have a reference handy for the reproductive disturbances, but the study basically found that women who were chronically exposed to nitrous had difficulty becoming pregnant. It should be noted that these health effects are the result of CHRONIC exposure; a single balloon at a Dead show (or a single visit to the dentist) is unlikely to be a problem for a healthy individual.
Aside from its psychopharmacological actions, nitrous oxide has one other (known) significant metabolic action: it interacts with vitamin B12. This was first reported in an in vitro study in 1968, but didn't really receive notice from anaesthesiologists until ten years later (because medline didn't exist yet :-) ). In 1978, however, Amess et al showed that 24 h of nitrous oxide administration caused interference with DNA synthesis in humans. Since then, the interaction between nitrous oxide and B12 has been better characterized.
Basically, B12 is a bound coenzyme of methionine synthase and has a tetrapyrrole rings with a monovalent cobalt at the center. The cobalt functions as a methyl carrier in a transmethylation reaction. Nitrous oxide converts the cobalt from the monovalent form to the bivalent form. As a result, methionine synthase activity is inhibited. Recovery is believed to require absorption of new unoxidized B12 (and synthesis of new apoenzyme).
Humans seem to be far more resistant to complications from this than rodents. I don't have the energy to go through the various published studies at this point, so I will quote from Nunn's "Clinical Aspects of the Interaction Between Nitrous Oxide and Vitamin B12" (1987), _Br. J. Anaesth._ 59: 3-13.
It seems likely that in man, in contrast to the rat, exposure
of less than 30 minutes will not cause any measurable change in
methionine synthase activity.  In combination with a wealth of
clinical experience, this suggests that there is no special
hazard for short exposures to nitrous oxide.  There is a variable
response to exposures lasting between 30 minutes and 2 h.  However,
it now seems likely that exposures of more than 2 h are likely
to cause intereference with hepatic methionine synthase
activity.  The paucity of human data makes it more difficult to
say how long an exposure is required to cause significant
intereference with DNA synthesis.  It is likely that there will
be considerable individual variation and results obtained in
healthy patients cannot be extrapolated to the patient
who is seriously ill.  Nevertheless, it seems likely that,
once methionine synthase activity is inhibited, it will remain
so for days.
With respect to repeated exposures to nitrous, be aware that this effect can build up (Nunn gives "intervals of less than 3 days" as a cut-off).
Mandatory nitrous horror story: Layzer (in (1978) "Myeloneuropathy after prolonged exposure to nitrous oxide," _Lancet_ 2:1227) reports a case of 15 people who had been inhaling nitrous oxide for long periods of time and developed a condition resembling subacture combined degneration of the cord, whatever that means.
I would suggest that the following types of people in particular avoid exposure to significant amounts of nitrous:
  • Pregnant women: since nitrous oxide is a known teratogen in rodents, acting by depleting folates and partially reversible by oral folinic acid, we can expect a similar syndrome in humans.
  • Vegans who don't take B12 supplements: although documented cases of vegans with B12 decifiencies are scarce, theories on nutrition indicate that vegans are unlikely to get as much B12 as other groups of people.

You can find other references explaining the link between nitrous oxide and vitamin b12 and folic acid deficiency listed below:

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