Thursday September 3 2009
Leafy green vegetables can be a good source of folic acid
Experts have called for “wider folic acid use” according to BBC News, which reported that women of childbearing age have been urged by the Scottish Spina Bifida Association to take folic acid supplements even if they are not planning a family.
The news follows the release of a report by the Scottish Spina Bifida Association that says the number of Scottish babies born with spina bifida, the developmental neurological defect, appears to be rising. Apparently, 15 babies have been born with the condition since January this year, double the amount normally seen.
In 2007, the Food Standards Agency (FSA) recommended that folic acid, which helps prevent spina bifida, should be added to bread or flour. However, that recommendation is under review following new research that suggested it might increase the risk of colorectal cancer.
An alternative is to encourage pregnant women to take 0.4mg (400 micrograms) of supplemental folic acid until the 12th week of pregnancy. To ensure that enough folic acid is in the woman’s body around the time of conception, and during early development of the baby’s nervous system, women are advised to take the supplements well before becoming pregnant.
Where has the news come from?
It is unclear whether or not the rates of spina bifida reported in the first half of 2009 have been compared with expected rates through formal research and whether or not the reasons for the increase has been investigated. The idea that cases are increasing has been raised by the comments of Dr Margo Whiteford, a consultant geneticist and chair of the Scottish Spina Bifida Association. She said that the charity has “had as many contacts from families in the first half of the year as we'd expect to see for the full year”.
What is spina bifida?
Spina bifida is a type of ‘neural tube defect’ (NTD). These defects, which also include rarer conditions such as anencephaly, occur in human embryos if there is a problem with the normal development of the nervous system. At around 28 days after fertilisation the developing spinal cord is an open tube but it normally closes so that it is covered by bone and skin. If this process does not occur correctly, then spina bifida can result, potentially causing problems such as learning difficulties, disability or even an exposed spinal cord. The global rate of neural tube defects is about 2.6 per 1,000 pregnancies.
How can folic acid help?
Folic acid has been shown to help prevent birth defects, such as spina bifida. A systematic review of four trials involving 6425 women found that the chance of having a baby with a neural tube defect is reduced by about 75% if women take the supplements prior to conception and for the first two months of pregnancy (relative risk 0.28, 95% confidence interval 0.13 to 0.58).
Experts recommend that women wishing to conceive should start taking a daily 400 microgram (0.4mg) supplement of folic acid as soon as they stop using contraception. Women will need a higher dose of folic acid if they or their partner have a neural tube defect, a family history of neural tube defects or have previously had a baby with a neural tube defect. A GP can prescribe this higher dose.
The protective effect of folic acid during pregnancy goes beyond preventing neural tube defects. Supplementation with folic acid has been shown to reduce the risk developmental problems such as congenital heart defects, cleft palate, limb defects and urinary tract anomalies.
Is folate the same as folic acid?
Folate is the naturally occurring form of the vitamin that is found in food. Although folate and folic acid are not absorbed in the same way or to the same extent, they can be considered similar. One microgram of dietary folate is equivalent to around 0.6 microgrammes of folic acid supplement (also known as vitamin B9) taken with food.
What are ways to get folic acid in my diet?
You can get a certain amount of folate from leafy vegetables such as spinach and lettuce, or dried and fresh beans and peas. Some seeds and certain other fruits and vegetables are also rich sources of folate.
Other countries, notably the US, have fortified their flour to contain higher amounts of folic acid but fortified flour is not routinely available in the UK. However, a number of fortified cereals are available for sale, with some breakfast cereals containing 25% to 100% of the recommended dietary allowance (RDA) of folic acid.
Is folic acid safe to take?
Folic acid is a vitamin and safe to take.
What is the controversy about adding folic acid to flour?
For unplanned pregnancies folic acid supplements may be taken too late to have an effect as they are essential in the first 28 days of development following conception. Other options for increasing the population’s intake of the vitamin are being considered, including a recommendation by the Food Standards Agency to add the vitamin to flour and bread.
Some parties are opposed to fortifying bread with folic acid but to date there have been inconsistent results in research linking dietary folate intake and various cancers. Some studies show small reductions in risk and others show small increases. This inconsistency may be due to problems in the design of these studies and so it is not yet certain if folate is linked to an increase or decrease in bowel cancer, particularly. This issue is being examined by experts before any decision about fortification of flour is made.