Getting enough of this B-vitamin could prevent many thousands of deaths a year from cardiovascular disease. It could also virtually halve the number of babies born with birth defects. Yet nine out of ten adults in Australia and New Zealand take in too little folic acid.
What it is?
This water-soluble B vitamin, also called folacin or folate, was first identified in the 1040s, when it was extracted from spinach. Because the body can't store it for very long, you need to replenish your supply daily. Cooking, or even long storage, can destroy up to half the folic acid in foods, so supplements may be the best way to get enough of this vital nutrient.
What it does?
In the body, folic acid is utilized thousands of times a day to make blood cells, heal wounds, build muscle – in fact, it's necessary for every function that requires cell division. Folic acid is critical to DNA and RNA formation, and assures that cells duplicate normally. It's especially important in fetal development, and also helps to produce key chemicals for the brain and nervous system.
Adequate folic acid at conception and for the first three months of pregnancy greatly reduces the risk of serious birth defects, including spina bifida. This B vitamin also appears to regulate the body's production and use of homocysteine, an amino-acid-like substance that at high levels may damage the lining of blood vessels, making them more susceptible to plaque build-up. This makes folic acid an important weapon against heart disease. In addition, it may be useful in warding off certain cancers, including those of the lungs, cervix, colon and rectum.
Folic acid may help depression. Because high levels of homocysteine may contribute to this condition, some experts think that folic acid (which is often deficient in people who are depressed) may be of value because it reduces homocysteine levels. Studies also show that taking folic acid improves the effectiveness of antidepressants in people with low folic acid levels. Folic acid supplements have been useful in treating gout and irritable bowel syndrome as well. Because high homocysteine levels may be a factor in osteoporosis, folic acid may even help to keep bones strong.
- Protects against birth defects.
- Reduces heart disease and risk of stroke.
- Lower risk for several cancers.
- Folic acid supplements, even at normal doses, may mask a type of anemia caused by a vitamin B12 deficiency. Unchecked, this anaemia can cause irreversible nerve damage and dementia. If you take folic acid supplements, be sure to take extra vitamin B12 as well.
- Reminder: If you have a medical or psychiatric condition, talk to your doctor before taking supplements.
How much you need?
The current adult RDI for folic acid is 200 mcg a day (increasing to 400 mcg for women during pregnancy). Supplements are advisable for older people, especially if they don't eat green leafy vegetables regularly.
If you get too little
Though relatively rare, a severe folic acid deficiency can cause a form of anaemia (megaloblastic anaemia), a sore, red tongue, chronic diarrhoea and poor growth (in children). Alcoholics and people who are on certain medications (for cancer or epilepsy), or who have malabsorption diseases (Crohn's, coeliac disease), are susceptible to a severe deficiency. Much more common is a low level of folic acid, which causes no symptoms but raises the risk of heart disease or birth defects.
If you get too much
Very large doses (5000-10000 mcg) offer no benefit, and may be dangerous for people with hormone-related cancers, such as those of the breast and prostate. High doses may also cause seizures in those with epilepsy. Some experts suggest an upper daily limit for folic acid of 1000 mcg for adults.
How to take it?
For overall good health and the prevention of heart disease: Take 400-800 mcg of folic acid a day.
For women who might become pregnant: Take a total of 800 mcg a day. (Adequate folic acid stores are important because the vitamin plays a role in a baby's development from conception.)
For people with depression: Take 400 mcg a day, as part of a vitamin B-complex supplement.
Guidelines for use
Folic acid can be taken at any time of the day, with or without food. When taking an individual folic acid supplement for any reason, combine it with an additional 1000 mcg of vitamin B12 to prevent a B12 deficiency.
Excellent food sources of folic acid include green vegetables (especially leafy ones), beans and whole grains. Some refined grain products are now fortified with folic acid.
- Buy a folic acid supplement that also contains vitamin B12 (since too much of one can mask a deficiency of the other). A combination supplement may be less expensive than buying each vitamin separately.
- For prevention of disease, the best way to get enough folic acid may be through supplements. In one small study, people taking 400 mcg of folic acid a day in pills or in specially fortified foods increased their folic acid level. But those who just ate foods naturally rich in folic acid showed no increase. Scientists speculate that the folic acid found naturally in foods may not be absorbed well enough to have a therapeutic effect.
- A preliminary study from Oxford University hints that folic acid may play a role in preventing Alzheimer's disease. People with the disease tended to have lower blood levels of folic acid and vitamin B12 than healthy people of the same age.
Did you know?
You'd need to eat 24 spears of asparagus a day to get the 400 mcg of folic acid recommended here for good health.