absorption of B vitamins from food

This topic contains 3 replies, has 1 voice, and was last updated by  Lynn_M 2 years, 8 months ago.

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  • #2879 Reply



    I was recently diagnosed with heterozygous mutation of both C677T and A1298C. This was after having a missed miscarriage at 9 weeks.
    My questions is about the B vitamins. Can I with this mutation absorb any B vitamins from food and if so what is the percentage? As I understand from all the articles and comments, we are not able to absorb the synthetic folic acid, but what about the folic acid, b12, b6 and b2 from food?
    I have all the symptoms of Riboflavin deficiency lasting now for 2 years, this started after I stopped taking the contraceptive pill (12 years on the pill). Do we have a reduced ability to use Riboflavin with this deficiency also? I didn’t have any symptoms before this…
    Thank you for any comments, I have been trying to figure this out for a few days now.

    #2882 Reply


    MTHFR does not impact the absorption of B vitamins from food. Absorption is the ability of nutrients to cross from the GI tract into the blood stream. What MTHFR impacts is the metabolic conversaion of inactive forms of folate (such as folic acid) and B12 to the active forms, which your body can use without any futher conversion steps. That conversion takes place in the cytosol of cells for folate and B12 and in the mitochondria for adenosylcobalamin.

    Folic acid is synthetic, so it is not found it food unless it has been added to it (the food has been “enriched”.) The reason to avoid food with added folic acid is that folic acid competes with the active forms of folate at the cellular receptors. Folic acid takes up the places at the table (receptors)which doesn’t leave anyplace for the active folate, so the folate doesn’t get taken into the cell.

    Vitamin B12 is a very large molecule, and normally a person has intrinsic factor produced by the parietal cells of the stomach. It helps the intestines absorb B12. Some people do not make enough intrinsic factor or have a condition that destroys it, so taking B12 orally doesn’t do any good. In that case, taking comparatively huge amounts of active B12 via injection or sublingually causes the cells to absorb the B12 through passive diffusion. Our bodies use up only about 1 mcg of B12 daily, so taking 1,000 mcg is a comparatively huge amount. Taking B12 sublingually, via injection, or transdermally bypasses the difficult process of the very large B12 molecule being taken up in the intestine.

    For discussion of B2 (riboflavin) issues, see http://forums.phoenixrising.me/index.php?threads/b2-i-love-you.15209/page-9. Look at pages 9 and 10.

    The short answer is that the other B vitamins rely on B2 to be activated or converted or used correctly. If you have MTHFR and take folate and B12, thereby increasing methylation and folate use, you put more demand on needing other support nutrients, and you increase the need for B2. Anyone taking a B complex or juicing, which concentrates nutrients (but not much B2 in veggies compared to the other B’s), also slowly depletes the storage locations of B2. The other bad thing about taking a complex is that you can absorb the several thousands of % of the other B’s they put in them. But you can only absorb a fraction of the B2 so the complex itself is unbalanced.

    #2886 Reply


    Thanks Lynn,
    You have been very helpful, but I am still not 100% clear on few points and I think this is my fault because of using the wrong terminology… I don’t understand whether my body is able to use any of the active folate (or whatever it is called) and B12 from food at all…since I have heterozygous mutation whether the body can compensate for the mutation with the other correct part of the gene.
    About B2, it makes perfect sense and I didn’t know this. I was taking a B-complex, which I have now stopped and I ordered the following:
    Solgar Folate Metafolin Folic Acid
    Solgar Sublingual Methylcobalamin (Vitamin B12)
    Solgar P-5-P, 50 mg,
    Riboflavin 5′ Phosphate
    Also I now understand I should be taking more Riboflavin to compensate. Also what about the rest of the B-group vitamins, will I become deficient if I only take the 4 above supplements? Do you know what amounts I should be taking?
    Thanks a million, I am very grateful there are knowledgeable people about this matter.

    #2894 Reply


    I person with homo A1298C has 60% of normal MTHFR enzyme activity, homo C677T has less – maybe 30-40%, if I’m remembering correctly. I don’t know the figure for compound hetero, but it’s probably inbetween the two. So yes, you can still use some of the active folate and B12 from food.

    I can’t tell you amounts on the other B-vitamins. It partially depends on what you get from foods and superfoods. You might be able to take a B-complex of active forms of the B’s plus suplement riboflavin 5′ Phosphate separately.

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