Wednesday, May 29, 2024

Folate – Vitamin B9

What is folate?

Folate, also known as vitamin B9, represents all of the compounds called folates that occur naturally in foods and dietary supplements. 

Folate is one of the B vitamins that are primarily responsible for helping the metabolism of food to energy.  Folate is an essential vitamin, which means that the body does not synthesize it and it must be obtained through the diet. 

It is also a water-soluble vitamin, which means that it is not readily stored in the body and it must be consumed on a regular basis to ensure optimal health. 

Where is folate (vitamin B9) found?

Folate is found in many different foods, however, some foods with the highest amounts of folate include spinach, asparagus, brussels sprouts, and liver. 

Some other plant-based sources include dark leafy greens, fruit, nuts, beans, peas, and grains. 

Some animal-derived sources include poultry, eggs, and dairy products.

Many countries including the United States and Canada fortify their grain products with folate, making it easier for people to meet their nutritional needs. 

The supplemental form of folate is folic acid, which is found in folic acid supplements, multi-B complex vitamins, and many multivitamin supplements. 

It is also found in prenatal vitamins as it is an important vitamin for fetal development.

Why is folate important?

Folate (vitamin B9) is a very important nutrient. 

Folate helps the metabolism of amino acids and the synthesis of nucleic acids, which make up DNA. 

In addition, folate is thought to decrease the risk of health problems in a developing fetus, such as spina bifida, which is a condition where the structure of the spinal cord is abnormal. 

For this reason, it is important that pregnant women or women of childbearing age consume adequate amounts of folate.

What is the RDA for folate?

The Recommended Dietary Allowance (RDA) for folate is measured in dietary folate (vitamin B9) equivalents (DFE); one DFE is equivalent to 1mcg of folate from food, 0.6mcg of supplemental folic acid taken with food, or 0.5mcg of supplemental folic acid taken without food. 

This is because folate from food is not absorbed as well as folic acid from supplements.

The RDA for folate is 400 DFE for men and women 14 years of age and above, and 600 DFE and 500 DFE for pregnant and lactating women, respectively. 

The RDA is 300 DFE for children between nine and thirteen, 200 DFE for children between four and eight, 150 DFE for toddlers between one and three years, 80 DFE for infants between seven and twelve months, and 65 DFE for infants under seven months of age. 

Folate can be passed through breast milk if the mother has adequate folate levels, and it is also added to infant formulas.

These values are given by the National Institutes of Health, and the RDA represents the daily intake sufficient to meet the dietary needs of 97 to 98 percent of healthy individuals. 

Half of a cup of boiled spinach contains 33 percent of the RDA, and half of a cup of cooked enriched white rice contains 22 percent of the RDA.

How much is too much?

The Upper Limit (UL) for folate is 1000mcg for men and women above 19 years of age and 800mcg for teenagers between 14 and 18 years of age. 

The UL for folate is 600mcg for children between nine and thirteen, 400mcg for children between four and eight, and 300mcg for toddlers between one and three years of age. 

There is no established UL for infants under one year of age. 

These values are given by the National Institutes of Health, and the UL represents the maximum daily intake that is unlikely to cause adverse health effects. 

Research suggests that continuous excessive intake of folate could increase the risk of potential health consequences. 

For example, one study found that mothers taking folate supplements of dosages above 1000mcg during conception had children scoring lower scores on cognitive development tests than those who took supplements between 400 and 999mcg. 

Another study of 30 healthy adults found that taking 5 milligrams (mg) of supplemental folic acid daily was associated with a decreased number of natural killer cells. 

Natural killer cells are a vital part of the adaptive immune system, and they help protect the body against infection from viruses and bacteria. 

This could potentially mean that large doses of folic acid could have detrimental effects on the immune system, however, more research is needed to confirm this. 

It is important to note that 5 milligrams are significantly more than the RDA for folate, as one milligram is equivalent to 1,000 micrograms (mcg).

Large amounts of folic acid may help disguise the symptoms of B12 deficiency, which could potentially have damaging effects on the nervous system if it is not treated.

What are the benefits of folate?

Aside from potentially helping to protect against birth defects, folate might also have other benefits. 

Some studies show that sufficient folate intake has been associated with a lower risk of many types of cancers, including lung, colorectal, breast, and ovarian cancers. 

More research is needed to confirm this relationship.

One study found that folic acid may help reduce the risk of stroke, and this may be due to the fact that folic acid helps lower homocysteine levels. 

Some studies have shown that taking folic acid supplements during pregnancy was associated with a decreased risk of Autism spectrum disorder (ASD) in children. 

However, the evidence is inconclusive, and more research is needed on this topic.

Folate deficiency

Folate deficiency is relatively rare in developed countries; however, some groups may be more at risk of deficiency than others. 

First, people with alcoholism or alcohol use disorder may be at an increased risk of deficiency because alcohol inhibits the absorption of folate. 

People with conditions such as celiac disease and inflammatory bowel disease might also have a decreased ability to absorb folate, so these groups should watch their folate consumption.

Pregnant women also are at a higher risk of folate deficiency because folate requirements increase during pregnancy. 

For this reason, it is recommended for pregnant women and women of childbearing age to watch their folate consumption and potentially include a folic acid supplement.

Folate deficiency often results in megaloblastic anemia, which is when the red blood cells become too large in size. 

Symptoms of megaloblastic anemia may include fatigue, headache, difficulty concentrating, weakness, and shortness of breath. 

Folate deficiency can also produce lesions in the mouth, elevated homocysteine levels, changes in hair and skin pigmentation, or gastrointestinal disturbances. 

In addition, pregnant women with folate (vitamin B9) deficiency have a higher risk of having children with neural tube defects such as spina bifida.

Folate Supplementation

Folate deficiency can, fortunately, be treated by taking folic acid supplements, usually over a period of four months. 

It can also be prevented by consuming enough dietary folate.

If you think you have a folate deficiency or are at an increased risk, consider getting your blood levels tested. 

As always, consult your doctor before you begin taking any vitamin or mineral supplement, to make sure your medications or health conditions don’t make it a serious risk. 


Bibbins-Domingo, K., Grossman, D. C., Curry, S. J., et al (2017). Folic acid supplementation for the prevention of neural tube defects: Us preventive services task force recommendation statement. JAMA, 317(2), 183-189. doi:10.1001/jama.2016.19438

Levine, S. Z., Kodesh, A., Viktorin, A., Smith, L., Uher, R., Reichenberg, A., & Sandin, S. (2018). Association of Maternal Use of Folic Acid and Multivitamin Supplements in the Periods Before and During Pregnancy With the Risk of Autism Spectrum Disorder in Offspring. JAMA Psychiatry, 75(2), 176. doi:10.1001/jamapsychiatry.2017.4050

Office of Dietary Supplements – Folate. (2020, June 3). Retrieved August 29, 2020, from

Paniz, C., Bertinato, J. F., & Rodrigues-Lucena, M. (2017). A Daily Dose of 5 mg Folic Acid for 90 Days Is Associated with Increased Serum Unmetabolized Folic Acid and Reduced Natural Killer Cell Cytotoxicity in Healthy Brazilian Adults. J Nutr, 147(9), 1677-1685. doi:10.3945/jn.117.247445

Valera-Gran, D., Navarrete-munoz, E. M., De la Hera, M. G., et al (2017). Effect of maternal high dosages of folic acid supplements on neurocognitive development in children at 4-5 y of age: The prospective birth cohort Infancia y Medio Ambiente (INMA) study. American Journal of Clinical Nutrition, 106(3), 878-887. doi:10.3945/ajcn.117.152769

Vitamin B12 or folate deficiency anaemia symptoms and treatments. (n.d.). Retrieved August 29, 2020, from

Image by Evita Ochel from Pixabay 



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