Folate, B12 and the Folate Trap - Martyn’s Blog

[fbirder]

Martyn Hooper’s latest blog posting talks about a patient who was given 5000 mcg of folic acid a day - despite having a B12 deficiency that couldn’t be treated until after Xmas.

In his post Martyn mentions the Folate Trap - I thought I’d explain what that is.

Folate is a term used by biologists to cover a group of chemicals all with a similar structure. Different folates take part in different biochemical reactions. Normally we are interested in just one (because it also involves B12). That is the conversion of homocysteine to methionine. The attached image shows how this happens.

You can see from the diagram that methylfolate and cob(II)alamin (from B12) work together in the reaction. In the process the methylfolate is converted to tetrahydrofolate, which is then available to go around the cycle again - or to take part in other reactions. Many of these other reactions involve DNA (see diagram).

If there’s not enough B12 in the body then this conversion cannot take place at the normal rate. And this is the only way that methyltetrahydrofolate (AKA methylfolate) can be converted to anything else. Without enough B12 the methylfolate builds up.

Which wouldn’t be too bad, except that all other forms of folate (that get used in other reactions) will, eventually, get converted to methylfolate. And that’s where it will get stuck.

Slowly the majority of folate in the body is methylfolate - which is useless. All the other forms of folate aren’t available, so the reactions that involve them aren’t progressing as they should. The patient starts getting ill.

But the blood test measures all forms of folate. So it sees a lot of folate present and doesn’t know it’s all methylfolate. Nobody is quite sure if these high levels of methylfolate are dangerous. Signs are that it might be.

Which is why folate shouldn’t be given in high doses until a B12 deficiency is ruled out or treated.

I've noticed that HU shrinks images. Here's a link to the full-size, readable, original - frankhollis.com/temp/B12%20...

[Sleepybunny]

Hi,

Link to the blog post

martynhooper.com/2018/12/20...

Link to article on folate deficiency which mentions risk of neuro damage if co-existing B12 deficiency is not treated at same time.

Folate Deficiency

patient.info/doctor/folate-...

BSH Cobalamin and Folate Guidelines

b-s-h.org.uk/guidelines/gui...

I am not medically trained.

[bookish]

Thank you, that is both interesting and helpful as was Martyn Hooper's post.

I wonder if it could shed some light on something my father said at the weekend - my grandmother (who had PA, as did her mother) was told when diagnosed not to supplement folic acid (or possibly folate) as 'it is poison to your system'. This would be 40+ years ago.

Unfortunately I have been supplementing my B12 for 20 years (suggested based on symptoms) so have no idea how low it was or if it was even tested. I was unaware of the family history at that point. My blood folate seemed reasonable but then dropped so I started to supplement fairly recently. Looks as if I may have to stop both for some considerable time (and try to get hold of old blood tests, if any were done).

[fbirder in reply to bookish]

People with a B12 deficiency need exactly as much folate as do those without. No more, no less. Although people with PA and, hence, low stomach acid, may need more in their diet. The idea that folic acid may not be good for people with PA was nonsense then and is still nonsense now. Doesn't stop some people from repeating it though.

Why do you think you need to stop both B12 and folate? I would continue with them both.

[bookish in reply to fbirder]

Thanks for your reply. I am getting increasing symptoms which could be B12 (although several other AI conditions - diagnosed vitiligo, plus possible Hashimoto's, Sjogrens, APS/Hughes all being investigated so considerable overlap) and am only producing low levels of antibodies to anything. Wondered if I am not actually absorbing enough of the B12 from tablets but no-one interested in symptoms, only blood levels which seem ok so no further action. To retest now for myself, suggestion seems to be a minimum of 1 month clear, some say 3. My liquid folate is 'use within 3 months' and just finishing that, so seemed like a good time to come off both and retest.