RSS
Home
Folic acid supplements in late pregnancy linked to increased asthma risk
Print
Email
RSS
Subscribe
Folic acid supplements are helpful in early pregnancy but may have consequences if taken later
An Australian study has found that women who take folic acid supplements past early pregnancy have a 30% higher chance of having a child with asthma.
The researchers at the University of Adelaide identified a link between folic acid supplements taken in late pregnancy and allergic asthma in children aged between 3 and 5 years, suggesting that the timing of supplementation in pregnancy is important.
According to Associate Professor Michael Davies, "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."
Davies further said that folic acid supplements -- recommended for pregnant women to prevent birth defects -- appear to have "additional and unexpected" consequences in recent studies in mice and infants. "Folate is incredibly important because of its role in preventing neural tube defects (like spina bifida) but because it is so important, and so bioactive, it needs to be treated with some respect as well."
Folates play a vital role in fetal development and deficiencies are linked to neural tube defects. Folate deficiencies may have other adverse affects on babies, as well. Studies have linked low folate levels in mothers with increased risk of ADHD in their children and smaller head circumferences, which could indicate a smaller rate of prenatal brain growth.
However, scientists are increasingly wondering if regular folic acid supplementation is necessary, and whether it may actually be harmful. As many countries have mandatory folic acid fortification (such as the U.S.) or are considering it, some studies are showing that this could lead to an overdose effect and increase in certain cancers. Folic acid supplements have been linked to lower risk of some cancers during early pregnancy but increased cancer risk after birth, for instance.
For the general population, folic acid supplementation can lead to other health problems as well. Dr Siân Astley of Britain's Institute of Food Research says of overfortification:
"This can cause problems for people being treated for leukaemia and arthritis, women being treated for ectopic pregnancies, men with a family history of bowel cancer, people with blocked arteries being treated with a stent and elderly people with poor vitamin B status. For women undergoing in-vitro fertilisation, it can also increase the likelihood of conceiving multiple embryos, with all the associated risks for the mother and babies. It could take 20 years for any potential harmful effects of unmetabolised folic acid to become apparent."
While these risks are associated with folic acid supplements, there is currently no risk associated with folates obtained from food. Why the difference? Folic acid is the synthetic version of folate. Unlike folates, which are metabolized in the stomach, folic acid is metabolized in the liver. The liver is easily saturated and excess folic acid enters the blood stream where it can harm other systems.
Good sources of natural folates include asparagus, spinach, beans and liver. This chart shows the folate and folic acid levels in many foods. Note that many cereals are fortified with up to 100% of the RDA for folic acid and prenatal viamins can contain double this amount as well. While pregnant women need more folate in early pregnancy (600 micrograms instead of 400), it may be wise to pay attention to intakes from all of these sources and to obtain as much folate as possible from a healthy diet.
Related Articles:
Comments
