Folic Acid in Pregnancy…
Too Much of a Good Thing??
It’s been common knowledge for quite some time now that folic acid supplementation before pregnancy and in the first 3 months of pregnancy reduces the risk of babies developing neural tube defects (e.g. spina bifida).
As usual many have taken this advice to the extreme by packing prenatal supplements with mega doses of folic acid (Vitamin B9), and the mother-to-be has been chugging it down believing that as this is a vitamin, and that there is no need to be concerned about over dosing on the stuff. In fact “the more the better” has been the rule of the day, at least until now.
Recent studies by Dr Michael Davies, associate professor with the Research Centre for the Early Origins of Health and Disease at the Robinson Institute in the University of Adelaide, have shown evidence that folic acid supplements taken in high doses in the later stages of pregnancy could have a direct relationship to young children developing asthma.
Children’s Asthma Risk Linked To Folic Acid Supplements during Late Pregnancy, Australian Study
Researchers in Australia have identified a link between allergic asthma in 3 to 5 year-old children and exposure to folic acid that their birth mothers took as supplements during late pregnancy. They said the timing of when folic acid is taken in pregnancy might be important. The researchers said the study may have revealed why childhood asthma has been on the rise in Australia and other developed countries over recent decades.
Dr Davies told the press that mothers are advised to take folic acid supplements during pregnancy to prevent birth defects, but research in mice and infants suggests this may also lead to “additional and unexpected” consequences. “In our study, supplemental folic acid in late pregnancy was associated with an increased risk of asthma in children, but there was no evidence to suggest any adverse effects if supplements were taken in early pregnancy,” he added.
Public health guidelines currently recommend that women supplement their diet with 400 micrograms of folic acid per day in the month leading up to and during the first trimester of pregnancy to reduce the risk of neural tube defects in children.Davies said this study supports this guideline, because they found no increased risk of asthma when the folic acid supplements were taken before or early in pregnancy.
He also emphasized that they found no evidence that asthma was linked to folate found naturally in foods like green leafy vegetables, some fruits and nuts.
(“Effect of Supplemental Folic Acid in Pregnancy on Childhood Asthma: A Prospective Birth Cohort Study.” American Journal of Epidemiology, (PDF) Vol 170, issue 10, 15th November 2009.)
What is folic acid and what are its functions?
Folic acid functions with vitamin B12 in many genetic, metabolic, and nervous system processes. Folic acid helps protect against heart disease, birth defects, osteoporosis, and certain cancers. It is vital to DNA and RNA synthesis, and therefore is critical to cell division, maintenance of the genetic code, regulation of cell division, and transfer of inherited characteristics. As many as 15% of people may have a genetic mutation causing higher homocysteine levels. This results in an increased risk for heart disease, and, in women, increased risk of having children with neural tube defects. Folic acid is essential to protein metabolism, notably for its role in reducing homocysteine levels by converting it to methionine.
Deficiency of folic acid has been linked to several birth defects, including the neural tube defect spina bifida. Up to half of neural tube defects are believed to be preventable if women of childbearing age supplement their diet with folic acid. Adequate intake of folic acid should begin several weeks before and continue through at least the first four weeks of pregnancy. Women who have previously had a child with neural tube defect can reduce the risk of recurrence by about 70% through supplementation with up to 4 mg folic acid per day in the pre pregnancy period and in the first three months of pregnancy. Studies suggest that the levels of folic acid necessary to prevent neural tube defects are more easily derived from fortified foods and supplements than from natural food sources alone.
Here are some of the locally available pregnancy supplements and their folic acid contents:
Prenatin (Soho) 800 micrograms (mcg)
Prenemia (Sanbe Forte) 1,500 mcg
Obimin (Zwellig) 1,000 mcg
Elevit (Bayer) 800 mcg
Pramilets (Abott) 500 mcg
Blackmores Pregnancy & Breastfeeding 250 mcg
Pregnancy Smart (Natures Way) 250 mcg
GNC Folic acid 1,000 mcg
GNC Prenatal formula 1,000 mcg
Folic acid is also naturally available in food. Some of the folic rich foods are liver, lentils, rice germ, brewer’s yeast, soy flour, beans and pulses, peanuts, spinach, whole wheat & asparagus. Naturally occurring folic acid is not readily available in adequate doses to have any effect on decreasing the risk of fetal abnormality.
I usually recommend that pregnant women are safe to, and in fact should supplement folic acid in a pregnancy multi- vitamin formula; however the dose should not exceed 400mcg after the first 12 weeks of pregnancy.
