Vitamin B9, a water soluble vitamin, is perhaps the most worshiped of all the micro-nutrients. Vitamin B9 is also known as folic acid, vitamin BC, folacin, and folate. Folate is the naturally occurring form of vitamin B9. Pteroyl-L-glutamic acid, pteroyl-L-glutamate, and pteroylmonoglutamic acid are also forms of vitamin B9.
Folic acid is not biologically active, but its biological importance becomes apparent after its conversion in the liver to digydrofolic acid, when tetrahydrofolate and other derivatives are produced. The terms folic acid and folic are derived from the Latin word folium, meaning “leaf.”
Vitamin B9: Functions in the Human Body
Vitamin B9 (folic acid) is renowned for its importance in early fetal development. Folic acid and folate are essential to nucleotide biosynthesis, remethylation of homocysteine and numerous other bodily functions. The body requires folate to synthesize DNA, repair DNA, and methylate DNA. Cell division and growth relies heavily on folic acid and both children and adults require it to produce healthy blood cells and avoid anemia. Low levels of folate can lead to homocysteine accumulation whereby DNA synthesis and repair are deeply affected and cancer development becomes a high-risk. Folic Acid is used to help treat Alzheimer’s disease, depression, anemia, and cancers.
Vitamin B9: Recommended Daily Intake
The recommended daily intake of vitamin B9 (folic acid/folate) is as follows:
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*1 DFE is defined as 1µg (microgram) of dietary folate, or 0.6µg of folic acid supplement. This system was devised due to the difference in bioavailability between folic acid supplementation and the variety of folate found in foods.
Folate deficiency is particularly dangerous in early pregnancy and can lead to fetal neural tube defects and brain defects. General folate deficiency can lead to depression, diarrhea, confusion, anemia, and glossitis. Like other B-vitamins, B9 deficiency is accelerated by alcohol consumption. Obese patients with NMIs greater than 50 are at higher risk of folate deficiency, as are those with celiac disease.
Vitamin B9: Risk of Overdose
Risk of toxicity from folic acid is low due to the fact that folate is a water-soluble vitamin excreted from the body through urine. A Tolerable Upper Limit (UL) has been set by The Institute of Medicine at 1mg for adult men and women and at 800µg for pregnant and lactating women less than 18 years of age. Exceeding the recommended vitamin B9 UL with supplementation can mask B12 deficiency. A 10000 patient study in 2007 concluded that excess folic acid consumption worsens the effects of B12 deficiency and may affect B12 absorption potential. Pregnant women should also be careful taking folic acid in the later stages of pregnancy. Research has shown that using folic acid supplements late in pregnancy increases the risk of childhood asthma by 30%.