Folate vs. Folic Acid: An Important Difference

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If I asked you to identify which form of Vitamin B9 (folate, folic acid or 5’-methyltetrahydrofolate) comes from plants, which is activated, and which can potentially be dangerous to your health, would you know the answer? If not, you’re in good company - it seems that consumers, supplement companies, and even nutrition experts alike are easily confused; some would even argue that they’re all the same.


While they are all the ‘same’ in that they’re different forms of the same vitamin (vitamin B9 or ‘folate’), there are some pretty significant differences in how the human body identifies and utilizes each of them.


What’s the difference?


Vitamin B9 is a water-soluble vitamin that has a vast array of functions in the body (likely the most well known is its role in the prevention of neural tube defects during pregnancy).  Vitamin B9, in its active state, is called ‘tetrahydrofolate’ – but that’s not something you’ll usually read on a label.


‘Folate’ generally refers to tetrahydrofolate derivatives that are found naturally in food (think green leafy veggies), whereas ‘folic acid’ is the term used to describe the synthetic compound used in food fortification and some supplements


In the body, the form of folate that enters metabolic pathways is tetrahydrofolate (THF) – this is usable B9.  In order to use folate or folic acid, the body must convert them into THF.  Natural folates are generally easily metabolized to THF in the mucosa of the small intestine.  Folic acid, however, is passed through the liver where it must be converted by an enzyme called dihydrofolate reductase into usable THF.  Usually, these pathways work, and the body derives the THF that it needs. 


However, there have been several studies that show the presence of unmetabolized folic acid in the blood after consumption of folic acid supplements or fortified foods.  Which means that when you take folic acid supplements, some gets converted to THF, and some doesn’t.


And, unfortunately, there are risks associated with excessive unmetabolized folic acid floating around in your blood.


Perhaps the scariest is the risk of increased cancer outcomes and all-cause mortality (death from any cause) with excessive supplementation of folic acid.  Other studies have shown an increased risk of colon and prostate cancer with plain folic acid supplementation.  High folic acid intake can also mask a B12 deficiency,  leading to a deterioration of cognitive function in the elderly if folic acid is taken alone. 


However, folate from plant sources is still an extremely important nutrient for good health.  It reduces homocysteine (a marker of inflammation and cardiovascular disease risk), supports the nervous system, and aids in the production of red blood cells.  It prevents neural tube defects in newborns and is essential during pregnancy.


So how can you be sure that you’re getting the good stuff, and not the one that can be potentially harmful to your health?


Read your labels.


When you’re buying a prenatal vitamin, a multivitamin, or a B complex – look to where it says folic acid and check the form (usually in brackets).  You’re looking for either ‘folate’ or ‘5’methyltetrahydrofolate' (5'MTHF).  This latter form is useful for those who have a genetic defect in their ability to methylate THF, another important metabolic step, so I often recommend all patients look for 5’MTHF, especially if they’ve had trouble trying to conceive.  For patients with digestive concerns, even B9 as 'folate' can be an issue, as the conversion to THF in the small intestine can be diminished.  In this case too, you'll want to consider using the activated 5'MTHF form.  A few brands that definitely use 5’MTHF are Thorne, AOR, and Douglas Labs


It is possible to test for an MTHFR genetic deficiency.  For patients who are at high risk or are curious to know, I'll often recommend testing.  We've found MTHFR gene deficiencies in patients having trouble trying to conceive and often see it paired with high inflammatory markers (homocysteine, CRP).  It's something to consider if your inflammatory markers are high for an unknown reason.  If you are curious about your MTHFR gene status, or would like more information on the testing and treatment available, call the clinic to book a free 15 minute consultation with me.  



In health,


Dr. Kali MacIsaac HBSc, ND
Naturopathic Doctor