Evidence

Research on use of folate and oral folic acid supplements for specific conditions shows:

• Birth defects. Research has shown that folic acid supplements can prevent birth defects of the neural tube. Taking a daily prenatal vitamin — ideally starting three months before conception — can help ensure women get enough of this essential nutrient.
• Folic acid deficiency. Nutritional folate deficiency is treated with oral folic acid supplements. This type of deficiency is no longer a problem in many countries that fortify foods such as cereal and pasta with folic acid.
• Heart and blood vessel disease and stroke. Folic acid works with vitamins B-6 and B-12 to control high levels of homocysteine in the blood. Elevated homocysteine levels might increase your risk of diseases of the heart and blood vessels (cardiovascular disease).
• Cancer. Some research suggests that folate might reduce the risk of various cancers.
• Depression. Some evidence suggests that folic acid might be helpful in treating depression.
• Dementia. There isn't enough evidence to support folic acid supplementation for the prevention of dementia.