Just found this info on the Babycentre website:
Why do I need folic acid?
Because it's very difficult to eat enough foods rich in the vitamin to supply the amount that experts recommend you take in pregnancy.
Folic acid, also known as folate or folacin, is one of the B group of vitamins, also known as B9. Your body needs it to produce red blood cells, as well as norepinephrine and seratonin (chemical components of the nervous system. It helps make DNA (the body's genetic material), which normalises the brain's functions, and is a critical component of spinal fluid. Folic acid is also one of the few nutrients known to prevent neural tube birth defects, such as spina bifida, which, according to The Association for Spina Bifida and Hydrocephalus (ASBAH), affects one in every 1,500 babies born in the United Kingdom.
The Department of Health recommends that every woman who is thinking about pregnancy or is in the first third (trimester) of pregnancy to take a daily supplement of 400 micrograms (mcg) of folic acid and eat a folate rich diet to reduce her baby's risk of getting some types of birth defects. Women who don't get enough may also increase their chance of miscarriage. Once you are into your second trimester (from week 13), you may wish to stop taking the supplements, although continuing to take them throughout pregnancy won't harm you or your baby either.
How much folic acid do I need?
Before you conceive, you'd be wise to take a daily folic acid supplement containing 400 micrograms (mcg) of folic acid.
Women who have had one child with a neural tube defect have a higher risk of having other children with the same disability. In this case, and for those who are prescribed certain medications, doctors will prescribe these women to take a much higher dose of folic acid -- a five milligram (mg) tablet -- starting one month before conception, if possible, and continuing through the first three months of pregnancy.
If possible, it is important that the supplements are taken before conception because development is rapid and the fetus's neural tubes close during the first four weeks of pregnancy.
Should I take a supplement?
While experts recommend a daily supplement of 400 mcg folic acid, eating plenty of folate-rich foods is important, too. See below for suggestions on folate-rich food.
What are the best food sources?
Leafy green vegetables are a good source, so try to have a large bowl of salad daily. Other sources include:
• 11 Brussels sprouts: 127 mcg
• large jacket potato: 39 mcg
• 4 tbsp black eyed beans: 220 mcg
• 7 tbsp bran flakes: 113 mcg
• 25g / 1oz wheat germ: 100 mcg
• 4 spears steamed or boiled asparagus: 88 mcg
• medium sized papaya: 115 mcg.
• 2 spears steamed broccoli: 61 mcg
• large orange: 54 mcg
• large hard-boiled egg: 22 mcg
• 75g / 3oz tinned salmon: 17 mcg
FYI Delicate folic acid in foods is destroyed by overcooking, so cook in a covered pan with the minimum amount of boiling water. Try to eat vegetables lightly steamed, microwaved, or raw.
What are signs of a deficiency?
Folate-deficiency anaemia and iron-deficiency anaemia can have similar symptoms of fatigue and weakness. A mild folate deficiency may also leave you grumpy or edgy. If you have any concerns about your diet, speak with your GP, who may refer you to a dietitian.
Reviewed March 2006