Healthnotes Newswire — It is widely accepted among scientists and doctors that a common and devastating group of birth defects known as neural tube defects (NTDs) could be largely prevented if pregnant women consumed adequate amounts of folic acid during the very early stages of pregnancy. Indeed, the U.S. Public Health Service has recommended that "all women of childbearing age in the United States who are capable of becoming pregnant should consume 0.4 mg of folic acid per day for the purpose of reducing their risk of having a pregnancy affected with spina bifida or other NTDs." The amount of folic acid recommended to prevent these birth defects is nearly twice as much as that found in a typical American diet.¹

Therefore, a large majority of fertile women in the U.S. could benefit from increasing their intake of folic acid. And they should not wait until they become pregnant to do so, because the neural tube develops within two weeks of conception, before most women even realize they are pregnant. While it is possible to obtain 400 mcg of folic acid in one's daily diet by consuming abundant amounts of leafy green vegetables ("folic acid" was so named, because of its presence in "foliage"), many people simply do not eat enough "veggies." Moreover, it is not clear whether consuming a high folic acid diet would have the same protective effect as taking a supplement. The folic acid that occurs naturally in food has a different chemical structure than the synthetic folic acid in vitamin pills, and food-derived folic acid is not as well absorbed as its synthetic counterpart.² As all of the studies showing a protective effect against NTDs have used synthetic folic acid, it seems reasonable to recommend that women of childbearing age take supplemental folic acid every day.

However, because many women do not follow that advice—a recent survey showed that only 29% of women were taking a supplement that contains 400 mcg of folic acid—the U.S. Food and Drug Administration mandated in 1998 that all enriched-grain products be fortified with folic acid.³ Now, the British Department of Health has recommended similar fortification of grain products in the United Kingdom.

The benefit of folic acid fortification seems clear with respect to prevention of birth defects. In addition, there is circumstantial evidence that consuming more folic acid may help prevent heart disease and abnormal Pap smear (cervical dysplasia). However, not everyone is convinced that adding folic acid to grains is a good idea.

In an editorial in last Saturday’s British Medical Journal,⁴ two professors argue that universal fortification of grains may pose risks to certain individuals. Specifically, a high intake of folic acid may mask the laboratory diagnosis of pernicious anemia, a disease caused by vitamin B12 deficiency that can lead to permanent damage to the nervous system. Furthermore, folic acid may interfere with some drugs such as dilantin (used to treat epilepsy) and methotrexate (used to treat cancer and rheumatoid arthritis). The British Department of Health did consider these points and concluded that the benefits of fortification outweigh any potential risks. Nevertheless, the professors argue, it might be premature to accept the Department's conclusions, until a field trial is done to prove that fortification is both safe and effective.

It is not likely that such a field trial will ever take place. Given the strength of the evidence regarding folic acid and NTD prevention, many would consider it unethical to withhold fortified grains from a portion of the population, for the sole purpose of generating scientific data. Furthermore, it would be difficult to perform a study where one region of England consumed fortified grains and another did not, because so many modern foods are produced outside of the region in which they are consumed.

Despite the lack of definitive proof, it appears that England, like the U.S., will soon begin fortifying grains with folic acid. The ongoing challenge of this fortification program will be to provide enough folic acid to those who need it, without supplying excessive amounts to those who are already consuming enough.

Fortunately, folic acid is a relatively safe vitamin. Concerning the potential of folic acid to mask the diagnosis of pernicious anemia, doctors could still accurately diagnose the disease by measuring blood levels of the vitamin. What they would not be able to do is confidently rule out the diagnosis solely on the basis of a normal blood count. However, that limitation should not be a problem for astute physicians. Concerning the potential interference with prescription drugs, interactions with dilantin are unlikely to occur with the amount of folic acid present in a fortified diet.⁵ Possible interactions with methotrexate could be addressed on a case-by-case basis, and physicians could recommend appropriate dietary changes, if necessary.

It is clear that a significant proportion of the population could benefit from increasing their intake of folic acid. Although fortification of grains is not a perfect method of achieving that objective, it would appear to be an efficient way of correcting a widespread deficiency.