Vitamin B9 – Folate – What Is It?

Vitamin B9 is also known as folate or folic acid.  The word “folate” is derived from the Latin word “folium,” meaning “leaf,” because folate is found in dark green, leafy vegetables.  Folate is a water-soluble vitamin that is absorbed in the small intestine.  Between 10-30 mg of folate is stored in the body in the liver, in the blood, or in body tissues.

What Does It Do?

Folic AcidFolate is converted into five active coenzyme forms that accept and donate single-carbon groups that are necessary for the synthesis of DNA and the metabolism of various amino acids.  Since folate is necessary for DNA synthesis, it follows that it is also necessary for cell replication, especially during pregnancy and infancy.  Another important function of folate is that is involved in the formation of red blood cells as well as neurotransmitters in the brain.  Further, folate may help maintain normal blood pressure and reduce colon cancer risk.

Where Can You Find It?

Foods with FolateIn terms of amount and bioavailability, the best sources of folate are found in liver, fortified ready-to-eat cereals, other fortified grain products, legumes, and dark green, leafy vegetables.  Lesser sources include eggs, dried beans, and oranges.

As much as 50–90% of folate can be lost in the food preparation and cooking processes as this vitamin can be easily destroyed by heat, exposure to oxygen, and exposure to ultraviolet light.  Therefore, it is important to eat raw or lightly cooked fruits and vegetables in order to get the highest amount of bioavailable folate.

How Much Do You Need?

The RDAs for folate is shown below: 



Upper   Limit

Infants and children
0-6 months

65   mcg DFE

7-12 months

80   mcg DFE

1-3 years

150   mcg DFE

300   mcg DFE

4-8 years

200   mcg DFE

400   mcg DFE

9-13 years

300   mcg DFE

600   mcg DFE

Adolescents, 14-18 years

400   mcg DFE

800   mcg DFE

Adults, 19+

400   mcg DFE

1,000   mcg DFE


600   mcg DFE

1,000   mcg DFE


500   mcg DFE

1,000   mcg DFE

So, what is a DFE?  One Dietary Folate Equivalent (DFE) equals 1 mcg of dietary folate or 0.6 mcg of folic acid from a supplement.

What Happens If You Don’t Get Enough?

Baby with Spina Bifida

Baby with Spina Bifida

The most well-known folate deficiency is linked to neural tube defects in fetuses, which occur during pregnancy.  One neural tube defect is spina bifida, which is characterized by the spinal cord or spinal fluid bulging through the back due to incomplete closure of the embryonic neural tube.  People with spina bifida may exhibit paralysis, incontinence, hydrocephalus (water on the brain), and learning disabilities.  While surgery after birth may close the bulging area, it will not restore normal function to the affected spinal cord area.

Another neural tube defect is anencephaly, which is a condition where the neural tube at the cerebrum does not close.  Children born with anencephaly die shortly after birth.  A third neural tube defect is encephalocele, which is where other parts of the neural tube in the brain do not close.  This results in sac-like protrusions of the brain that exit the skull.  If the protrusion from the skull contains only spinal fluid, surgery may correct the problem and the child may make a full recovery.  If the protrusion contains brain tissue, it can result in the child suffering from neurologic problems, hydrocephalus, limb paralysis, an abnormally small head, mental and growth retardation, and seizures.

Folate sufficiency is necessary early on during pregnancy to prevent neural tube defects.  Unfortunately, the embryonic neural tube normally closes approximately 28 days after conception, which is early enough that many women may not even realize that they are pregnant.  Taking prenatal vitamins after this time will not help resolve the condition.

Megaloblastic anemia

Normal red blood cells (red) and megaloblastic cells (blue-purple)

Another disease related to folate deficiency is megaloblastic anemia, which affects red blood cell synthesis.  Since folate is necessary for cell replication, without sufficient quantities of this vitamin, cells cannot divide.  Therefore, red blood cells keep growing bigger in anticipation of dividing, but never do.  Mature red blood cells do not contain a nucleus, but immature cells do.  Since these large, immature cells cannot divide, they enter the bloodstream with their nuclei, making them easy to identify.

Folate deficiency is usually associated with a vitamin B12 deficiency.  Folate deficiencies may also be caused by chronic alcoholism, long periods of diarrhea, and certain chemotherapy medications.  Further, a folate deficiency may be caused by certain types of bariatric surgery.

What Happens If You Take Too Much?

There is a Tolerable Upper Limit for synthetic (not naturally occurring in foods) folate of 1,000 mcg for adults.  This is the amount of synthetic folate which can mask a vitamin B-12 deficiency.  As a note, there isn’t a UL for folate from foods as absorption is limited.

Bottom Line

The best way to consume any nutrient in order to avoid over- or under-consumption is to consume a wide variety of foods, in a wide variety of colors, and eat according to MyPlate.

Until next time, remember that… there are no excuses when it comes to your health!


2 thoughts on “Vitamin B9 – Folate – What Is It?

  1. Pingback: What Foods Fight the Effects of Aging?

  2. Pingback: Vitamin B9 or Folic Acid or Folate

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