What is Folic Acid?

Folic acid or folate is a B vitamin essential for normal cell growth and development. Read this article to learn more about the functions of folic acid in the body, the recommended intake doses, and the consequences of folate deficiency.

What Is Folic Acid?

Folic acid is the synthetic form of vitamin B9, also known as folate. Folate plays an essential role in a number of vital metabolic processes, from increasing DNA stability to preventing oxidation of DNA by free radicals. It is also crucial for red blood cell formation and healthy cell growth and function. 

Folate deficiency

Folate deficiency can cause an array of health issues, including megaloblastic anemia characterized by very large red blood cells that don’t function properly and an increased risk of heart disease and certain cancers. 

Pregnant women and women of childbearing age, people with alcohol use disorder, inflammatory bowel disease, or celiac disease are at increased risk of folate deficiency. In addition, drugs like methotrexate and sulfasalazine may affect folate absorption.

Dietary sources

Because the body doesn’t make folate on its own, you need to obtain this essential vitamin through dietary sources. A balanced diet usually provides all the folate you need. It is found naturally in many plant and animal foods, including:

  • Vegetables
    • Okra
    • Asparagus
    • Mushrooms
    • Avocado
    • Spinach
    • Kale
  • Fruit
    • Bananas
    • Melons
    • Strawberries
    • Oranges
    • Lemons
    • Grapefruit
  • Poultry
  • Red meat
  • Nuts
  • Beans
  • Eggs 
  • Yeast
  • Whole grains.

Since 1998, the Food and Drug Administration (FDA) has required food manufacturers to add folic acid to processed foods such as breakfast cereals, bread, pasta, white rice, and flour. 


Folic acid is available in concentrated form as a supplement and is often used in combination with other B vitamins. 

Common US folic acid brand names are:

  • FA-8
  • Folacin-800
  • FaLessa
  • Nature's Blend Folic Acid
  • ViloFane-Dp 75. 

Most multivitamins sold in the United States contain 100% of the recommended daily value of folic acid. 

Folic acid supplements are recommended for women who are planning to become pregnant, are pregnant, or breastfeeding. They can also be beneficial to people with poor diets or conditions that interfere with the body's ability to absorb folate like celiac disease.

Benefits of Folic Acid

Folic acid has numerous benefits, from building cells to treating anemia and preventing birth defects to reducing the risk of heart disease.

Builds cells

Folate helps the body make healthy red blood cells that carry oxygen to all the parts of the body. If your body doesn’t produce enough red blood cells, you are at risk of developing anemia. 

Treats anemia

Vitamin B keeps the blood healthy by helping red blood cells form and grow. Not getting enough folic acid can lead to folate-deficiency anemia, especially in women of childbearing age.

Lowers the risk of birth defects

Folic acid reduces the risk of serious birth defects of the brain and spine known as neural tube defects, for example, spina bifida and anencephaly. It may also help prevent other types of birth defects and early pregnancy loss. 

Helps prevent changes to DNA that may lead to cancer

Studies show that getting sufficient amounts of folic acid can help lower the chances of getting certain cancers, in particular colorectal cancer.

Promotes brain health

Research suggests that low folate levels and folate deficiency can lead to poor brain function and an increased risk of dementia and mental impairment in older adults. Folic acid supplements have been shown to improve brain function and help treat Alzheimer’s disease. They are also used to treat mental health disorders in combination with antidepressant medications.

Reduces risk of heart disease

Having elevated levels of the amino acid homocysteine in the blood, a condition known as hyperhomocysteinemia, is associated with an increased risk of developing heart disease and stroke. Folic acid supplements may reduce homocysteine levels and the chances of heart disease. 

Who Should Take Folic Acid?

Everyone needs folic acid to be healthy, but it is especially important for women of childbearing age and pregnant women.

Who can’t take folic acid?

Although most adults and children can take folic acid, it is not suitable for everyone. You should talk to your doctor before you start taking folic acid supplementation in the following cases:

  • You have a sensitivity or are allergic to synthetic folic acid or any type of medicine
  • You have epilepsy, type 2 diabetes, rheumatoid arthritis, or celiac disease
  • You have low vitamin B12 levels or suffer from pernicious anemia
  • You are undergoing a type of kidney dialysis called hemodialysis 
  • You have a stent in your heart.

Some people have hereditary folate malabsorption, a disorder that interferes with the body's ability to absorb folate from food and causes dangerously low folate levels. This condition requires individualized treatment. 

What Is the Recommended Daily Dose of Folic Acid?

The recommended daily dose of folate for adults is 400 micrograms (mcg). 

Women who are or might become pregnant should take 400–800 mcg of folic acid per day and those who are breastfeeding should aim to take around 500 mcg. 

People with spina bifida or a family history of neural tube irregularities are recommended to take 4,000 mcg of folic acid daily. 

Side Effects of Folic Acid 

If you take folic acid within the recommended daily dose limits, you are very unlikely to experience any side effects. You may feel mild and temporary nausea, unpleasant taste in your mouth, bloating, or loss of appetite. 

However, doses of folic acid that exceed 1,000 mcg per day may cause more significant side effects, such as:

  • Skin reactions
  • Confusion
  • Trouble concentrating
  • Sleep problems
  • Seizures
  • Nausea
  • Loss of appetite
  • Bloating, gas, and stomach pain
  • Bitter taste in your mouth
  • Feeling excited or irritable
  • Depression.

Some research suggests that taking high doses of folic acid, anywhere from 800 to 1,200 mcg daily, may increase the risk for cancer or heart attack in people with heart problems. 

In extremely rare cases, folic acid can cause a serious allergic reaction or anaphylaxis. Warning signs include skin rash, itching, redness, and difficulty breathing.