folic acid

Neural tube defects are serious birth defects that occur during pregnancy. According to a recent study, taking folic acid supplementation during or while planning to become pregnant is a preventative measure for neural tube defects in babies.


Neural tube defects are birth defects of the spine, spinal cord or brain. The major problem with this defect is that it occurs so early within the pregnancy, usually during the first month before the woman even knows she is pregnant, making it harder to detect and treat.  Neural tube defects are among the most common major congenital anomalies in the United States and may lead to a range of disabilities or death.

The most common neural tube defects are anencephaly, which refers to an underdeveloped brain and an incomplete skull and spina bifida, the incomplete closing of the spinal cord. According to data from 2009-2011, there are an approximate 6.5 cases of anencephaly and spina bifida combined per 10000 live births.

To reduce these rates and as a preventative measure, an article published in the Journal of the American Medical Association (JAMA) suggested that daily folic acid supplementation intake, between conception and the early stages of pregnancy, termed as periconceptional stage, can prevent neural tube defects. Moreover, since most women do not receive the recommended daily intake of folate from diet alone according to the National Health and Nutrition Examination Survey, this study suggested that extra supplementation in addition with foods rich in folic acid are necessary. Folic acid is a synthetic form of folate, which is a water-soluble B vitamin. Folate occurs naturally in foods such as dark green leafy vegetables, legumes, and oranges.

In 2009, the US Preventive Services Task Force (USPSTF) analyzed the effectiveness of folic acid supplementation in women to see if it would prevent neural tube defects. The USPSTF did not review the evidence on folic acid supplementation in women with a history of pregnancy affected by neural tube defects or other high-risk factors. Further reviews by the USPSTF included determining the harm and benefits of folic acid, dosage, timing relative to pregnancy, duration of taking the supplementation and race/ethnicity.

Findings from this study presented that the effectiveness of folic acid supplementation in women of childbearing age had greater benefits than harm. However, the importance of the dosage was affirmed – if the right amount is not taken it could cause harm. The USPSTF recommends that all women who are planning or capable of pregnancy take a daily supplement containing 0.4 to 0.8 mg (400-800 μg) of folic acid. In relation to timing, to gain the efficiency of the supplementation preventing neural tube defects, the critical period was found to be at least one month before conception and continued through the first two to three months of pregnancy.

In 1998, the US Food and Drug Administration implemented food fortification laws where the prevalence rates of neural tube defects in infants decreased that year. Food fortification is the addition of key vitamin and minerals, for example, iron, folic acid, iodine, vitamin A, and zinc, to food. These additives improve food’s nutritional content and help with nutritional gaps in a population. As a result of this, it was found that prevalence rates of neural tube defects were 10.7 cases per 10 000 live births before the implementation of food fortification during 1995 to 1996, and then declined to 7 cases per 10 000 live births after fortification from 1999 to 2011. Therefore, the USPSTF pointed out that there was a correlation between the food fortification laws and a reduction in neural tube defect rates, however, extra supplementation would be required for to achieve an optimal folic acid level.

Even though some harmful effects were taken into consideration and tested based on too high of a dosage of folic acid, the results did not show a strong correlation and the USPSTF concluded that the symptoms could be caused by something that cannot completely be correlated to folic acid. Lastly, they emphasized that folic acid supplementation is highly recommended for women of childbearing age. Moreover, they stated that it is important for all women who are planning or capable of pregnancy to take a daily supplement containing 0.4 to 0.8 mg (400-800 μg) of folic acid.


Written By: Seema N. Goolie, BSc

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