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The Little Known (But Crucial) Difference Between Folate and Folic Acid


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If I asked you which of these vitamins was found naturally in food, folate or folic acid, would you know the answer? If not, you’re in good company. Medical professionals, nutrition experts, and health practitioners frequently mix up the two, simply because the terms are often used interchangeably.

Many health professionals would even argue that folate and folic acid are essentially the same nutrient. While folic acid is often considered to be a supplemental form of folate, there is an important distinction between these two different compounds. For women past childbearing age, and for men in general, excessive doses of the synthetic form of this nutrient are not necessary, and may even be harmful.

The difference between folate and folic acid?

Folate is a general term for a group of water soluble b-vitamins, and is also known as B9. Folic acid refers to the oxidized synthetic compound used in dietary supplements and food fortification, whereas folate refers to the various tetrahydrofolate derivatives naturally found in food.

The form of folate that can enter the main folate metabolic cycle is tetrahydrofolate (THF). (2) Unlike natural folates, which are metabolized to THF in the mucosa of the small intestine, folic acid undergoes initial reduction and methylation in the liver, where conversion to the THF form requires dihydrofolate reductase.

The low activity of this enzyme in the human liver, combined with a high intake of folic acid, may result in unnatural levels of unmetabolized folic acid entering the systemic circulation.

Several studies have reported the presence of unmetabolized folic acid in the blood following the consumption of folic acid supplements or fortified foods. (3) Human exposure to folic acid was non-existent until its chemical synthesis in 1943, and was introduced as a mandatory food fortification in 1998. (4) Food fortification was deemed mandatory due to overwhelming evidence for the protective effect of folic acid supplementation before conception and during early pregnancy on the development of neural tube defects (NTD) in newborns.

Risks associated with excessive folic acid intake

While the incidence of NTDs in the United States been significantly reduced since folic acid fortification began, there has been concern about the safety of chronic intake of high levels of folic acid from fortified foods, beverages and dietary supplements. (5) One of the major risks associated with excessive intake of folic acid is the development of cancer. (6) In patients with ischemic heart disease in Norway, where there is no folic acid fortification of foods, treatment with folic acid plus vitamin B12 was associated with increased cancer outcomes and all-cause mortality. In the United States, Canada, and Chile, the institution of a folic acid supplementation program was associated with an increased prevalence of colon cancer. (78) A randomized control trial found that that daily supplementation with 1 mg of folic acid was associated with an increased risk of prostate cancer. (9)

Researchers have hypothesized that the excessive consumption of folic acid in fortified foods may be directly related to the increase in cancer rates. Excess folic acid may stimulate the growth of established neoplasms, which can eventually lead to cancer. The presence of unmetabolized folic acid in the blood is associated with decreased natural killer cytotoxicity. (10) Since natural killer cells play a role in tumor cell destruction, this would suggest another way in which excess folic acid might promote existing premalignant and malignant lesions.

A high intake of folic acid might mask detection of vitamin B12 deficiency and lead to a deterioration of central nervous system function in the elderly.

In one study, consumption of folic acid in excess of 400 micrograms per day among older adults resulted in significantly faster rate of cognitive decline than supplement nonusers. (11) Another study found a higher prevalence of both anemia and cognitive impairment in association with high folic acid intake in older adults with a low vitamin B12 status. (12) As vitamin B12 deficiency is a common problem for many older adults, these studies suggest that high folic acid intake could cause serious cognitive consequences in the elderly.

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Folate from natural food sources is best

Despite the risks associated with high levels of folic acid intake, it is well established that adequate folate intake from the consumption of folate-rich foods is essential for health.

Folate aids the complete development of red blood cells, reduces levels of homocysteine in the blood, and supports nervous system function. It is well known for its role in preventing neural tube defects in newborns, so women of childbearing age must be sure to have an adequate intake prior to and during pregnancy.

Excellent sources of dietary folate include vegetables such as romaine lettuce, spinach, asparagus, turnip greens, mustard greens, parsley, collard greens, broccoli, cauliflower, beets, and lentils. (13) Not surprisingly, some of the best food sources of folate are calf’s liver and chicken liver.

You can supplement with folate if your dietary intake is inadequate. Look for products that contain the Metfolin brand, or list “5-methyltetrahydrofolate” or “5-MTHF” on the label. Avoid products that say “folic acid” on the label. Make sure to check your multivitamin because most multis contain folic acid and not folate.

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The Adapt Naturals Core Plus bundle features two products that contain folate. Bio-Avail Multi, a multivitamin/multimineral and phytonutrient blend, contains 680 mcg of the most active form of folate, methyltetrahydrofolate. Bio-Avail Organ contains a blend of five organ meats (live, kidney, heart, pancreas, and spleen), which are among the highest sources of folate in the diet.

Women planning on becoming pregnant should consume between 800 and 1200 mcg of folate per day for several months before the start of pregnancy. Unless you’re consuming chicken or calf’s liver and substantial amounts of leafy greens on a regular basis, it’s difficult to obtain this amount from diet alone. If you’re pregnant or trying to get pregnant, I recommend supplementing with 600-800 mcg of folate per day, depending on your dietary intake. Solgar is a good brand, but there are several others that typically use 5-MTHF including Designs for Health, Thorne, Metabolic Maintenance and Pure Encapsulations.

All other people, such as men and older women, should be able to get plenty of folate in a diet with adequate vegetable consumption, and do not need to supplement.



Join the conversation

  1. Hey Chris,
    I started taking Pure Encapsulations Nutrient 950 with Vitamin K about a month ago. Before that I made sure to include Solgar Folate supplements a few months prior.
    Just wanted to comment that when I asked my OBGYN if Pure Encapsulations… was safe to take during pregnancy (we plan to start a family soon). She said not to take them and offered that I take 2 kid flinstone vitamins a day. Her concern was that it included vitamin k. I could not believe that was her answer and when I asked why, she did not have a reply.
    Thank you for the article and the Healthy Baby Code! They have helped me tremendously!

  2. Hi Chris, thanks for this article. I am 7 weeks pregnant and started taking prenatal supplements from xymogen which contain folate. I started the supplements on and off about 9 weeks ago and obviously when I found out I was pregnant I started to take them every day. My question for you is should I be worried because I didn’t start taking them months ago.? I have lupus and though I am now in remission I have always had problems with absorbing B12 and Iron and have shots a few times a year. Thanks you, Delia

  3. Folate reduces homocystine levels – YES! I hope followers don’t miss the important point that folate assists in the conversion of homocystine, which is essential for cardiac function. Monitoring folate levels in those who have a family history of heart attacks would benefit greatly from now knowing METHYLATED folate is not the same as folic acid. This info can save lives! Outstanding article!

  4. I had a baby with anencephaly. After that loss, the high risk OB that I saw told me to take 4000 mcg of folic acid to help prevent that again and I did for 5 years…….I stopped after having my second child. Now I am worried about the effects that taking the folic acid had, specifically cancer. Any thoughts? Can I reverse any bad results from the folic acid?

    • Do some reading on MTHFR.net. I think I recall that Niacin can help, but I’m NOT an expert.

  5. I started on Pure Encapsulations several weeks ago and my urine at first was neon green. I have decreased my water intake and try to take the pills in the middle of the meal and the color has improved (pale yellow). Why did this happen?

  6. Does this apply to other B-Vitamins? Specifically Riboflavin?

    I take over 200mg of vitamin b2 a day, 25mg of which are “activated b2”, but is there a natural vs synthetic form sold for that as well?

    • Just about any vitamin you take is synthetic unless it specifically states that it is derived from food. Synthetic vitamins are made by pharmaceutical companies and are big money. If your B vitamin has a chemical name after the vitamin name then it is synthetic. The sad thing is that even the most expensive so called high end natural supplement companies are just a bunch of over priced synthetic junk Stick to whole food supplements and superfoods. The best way to get concentrated whole food nutrients is too eat foods/supplements like Bee pollen, dessicated liver, green powders, brewers yeast etc or use companies like Mega food, New Chapter, Standard Process, Innate Response

    • Riboflavin depletes iron in the body, unless one is eating enough iron rich foods. 200 mgs of B2 is a LOT…

  7. I don’t know about folate/folic acid, but us chemists refer to everything sometimes as the base, sometimes as conjugate acid. These tend to be in equilibrium in a solution, going back and forth, thus, at least in solution oxalates = oxalic acid, folate = folic acid, etc. Especially in biology, as nothing is standalone and all is in solution in the body (or you have problems) When are a standalone chemical, such as a dry powder, or a strong acid or base, not named that way. Acetic acid, even a week solution is not usually called acetate unless it’s the salt form, such as sodium acetate, even when it’s as weak as vinegar.

  8. Hi Chris,
    I’m 10 wks pregnant with twins. My doctor just prescribed 200mcg folic acid in combination with my prenatal vitamins (New Chapter) which contain 600mcg folate (they also have K-2). Thanks to your article, I will skip her folic acid. Should I supplement my prenatals with 200mcg Solgar instead, or do I require more for twins? I do eat a paleo diet with some liver and lots of veggies.


    • I would try to find a multi with folate instead of folic acid, like Nutrient 950 with vitamin K. If you’re eating liver 2-3x/wk, and plenty of leafy greens, 400 mcg of folate should be fine.

      • Do you see any problem with eating raw liver during pregnancy (I’d prefer to freeze small pieces and take them like capsules). I use grass-fed sources from US Wellness Meats.

      • Hi Chris,

        If the supplement facts say Folate does that mean it’s OK? We got the “Perfect Prenatal” from New Chapter and it has 600mcg of Folate, but I can’t find if it comes from 5-MTHF or if it’s just re-badged folic acid….


  9. Do you have any idea of underlying cause for vitamin deficiencies. I have recently found that, I too, have very low levels of these two vitamins. Also have increased blood sugar. All diagnosed after being exposed to mold in my workplace for the last three years. Have made that connection on my own, but cannot get approval from workers comp to see anyone with mold exposure expertise to see me. Very concerned about other issues I may be having. Already have allergies, asthma, decreased heart rate, elevated BP……..but having to fight daily with WC to get the medical professional I need to tie all this into the mold issue or to rule out that possible cause. HELP.

    • I’m in the middle of testing for Pernicious Anemia but I think for me it’s diet – I’ve been a vegetarian for 12 years and never got much sun.

      It’s normal I’m told for these two deficiencies to cause a spike in Blood Sugar.

      • I have also found a connection between Pernicious Anemia and mold exposure. My B12 level was 168 on scale where 232 is lowest normal and 1140 highest normal. I don’t have the paperwork with me right now and am not sure about the Vitamin D, but doc has prescribed a Vitamin D tablet to be taken once weekly for 4 weeks. Manifested with low heart rate and visit to ER with referral to a cardiologist to diagnose. Don’t quite understand the entire physiology and what the mold does to interrupt normal absorption of B12 and D, but there is a definite connection. I do get a lot of sun despite knowing the dangers so that should not be an issue for me. Could you be in an environment with mold?

  10. Hi Everyone,

    As someone that found themselves with big B12 (156) and D3 (14.9) deficiency’s, I have been supplementing with Methyl B12 and D3 and have started to see all my symptoms disappear. I then started to add the Now Foods Co-Enzyme B Complex (because it was the only “B Multi” I could find with Methyl B12 – although I am also using the Jarrow B12 5000 mcg Losengers but I didn’t want a “B Multi” with Cyancobalamin B12)


    to make sure I was getting all my other B Vitamins, although I am eating two big helpings of spinach every day and so far my Folic Acid Blood work has been fine.

    On looking on the Now Foods ‘ingredients’ for the B Complex, it has 400 mcg of Folate but as ‘Folic Acid’ and I’m now wondering if I should keep taking these and if not, do I still need to be considering a ‘B Multi’ and if so, can someone recommend a brand with Methyl B12 and Folate ??



    • I’m a medical practice consultant, and most of our physician’s carry Isotonix Activated B-Complex, which contains 95% absorbable B vitamins, all in their active forms. B6 in the form of P5P, folinic acid instead of folic acid – which Chris also mentions http://chriskresser.com/folate-vs-folic-acid#comment-15581 , and methylated B12 (methylcobalamin), etc…

      The supplement is a powder which, when mixed with the proper volume of water, forms an isotonic solution, so it is comparable to receiving intravenous (IV) therapy of B-Vitamins when ingested on an empty stomach. Our doctors see very good clinical results in the patients’ lab work.

      If you find this information useful, you can purchase it in the health and wellness section at http://www.overtheamazon.com. (Disclaimer: It is my domain name referring you.)

    • Seeking Health is a good brand. The Dr. who specifies the formula is an expert in folate research and the MTHFR genetic defect.

  11. Hi dr. Kresser

    I’m confused by the distinction being made. From a biochemical standpoint, folate and folio acid coexist depending on pH. If you eat folate, it’s going to be reduced to folic acid in the stomach, then it could shift back to folate after being reduced by a healthy pancreatic secretion. Nevertheless, absorption of folate/folic acid has to take place in its reduced form (folate) to cross the cell membrane if GI epithelial cells. I don’t really understand the importance of the distinction since the pH of intracellular, extra cellular, and intra-compartmental environments is going to reduce/oxidize the vitamin as needed for different reactions. Thanks, dr. Kresser (writing from temple med)

  12. This is one of the reasons why I am not a big fan of supplements.

    By the way, this seems to apply to a number of conjugate bases/acids, which are often assumed to be the same thing – e.g., lactate vs. lactic acid.


    • I am a huge fan of supplements. IF you know what you are getting. The real problem lies in the lack of information or the outright misinformation, people thinking they can prescribe this stuff just because they’re a registered dietitian. If that’s all it took to give good advice then folic acid shouldn’t even be on the market, and I shouldn’t have to search on the Internet for a multi that has proper methylcobalamin in it for my B12 either.

      I mean, none of us have nutritional assay equipment in our households as far as I know. That stuff’s expensive. So we have no idea what the nutritional quality is of the food we’re eating. And everyone’s diet takes a nose dive every now and again, but their bodies still need the nutrients.

    • Active folates – not folic acid – may help mood if mood issues are related to poor methylation, and poor methylation is caused by folate deficiency or MTHFR deficiency. As I’ve pointed out in this article, folic acid is a synthetic form of folate that is not well metabolized, and should be avoided for that reason. Unfortunately it’s never so simple as “take this supplement for this symptom”.

      • In my country (Germany) the health department publishes recommendations containing the ‘folate equivalents’.
        They say that folate is only half as bioavailable as folic acid because of its poly-glutamate structure.

        Who’s right ?

    • It depends on a number of factors. Deplin (prescription form of folate) which is often given in these circumstances has 15 mg of folate. Most people don’t need that much, in my experience. I usually start with about 1 mg. It’s a good idea to run a methylation panel and make sure that overmethylation isn’t occurring with very high dose supplementation.

      • What is a methylation panel? I take 15mg l-methyl folate. It saved me. I backed down to 7.5 because I seemed to be getting too much. I feel the drop for sure. I was deficient in a lot of b vitamins. The functional medicine dr I was seeing was too expensive so I am going to see a registers dietician. I decided to do that after listening to your nutritionists on the ancestral rds podcast. I called your office for recommendations in my area but didn’t hear back.

  13. Folinic Acid is fine. Even those with genetic disorders can metabolize it, which is what the issue is in the first place. Folinic Acid does not require dihydrofolate reductase in order to be reduced to the active form of folate in the body.

  14. I have a liquid supplement that has folinic acid in it… what are your thoughts on folinic acid?

    • I agree with Mr. D – folinic acid (a.k.a. 5-formyl tetrahydrofolate) is one of the active folates and does not have any of the issues that folic acid does.

      • the never wrong wikipedia says:

        And Folinic Acid should not be administered to pregnant woman because it can weaken the unborn baby’s immune system