Thyroid UK
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B12, Folate and Ferritin

After a recommendation to read about B12 deficiency I have a few questions...

If I take it as read that B12 is important then.....

Correct Folate levels helps ensure that the B12 is converted from inactive to active forms which my body can use.


Once B12 levels increase (through injection or natural production by correcting folate for example)_ then Iron (Ferritin) use increases due to increased red blood cell production.

So you need to correct folate (1st ?) to see if this corrects B12. If not then take B12 injections (as I understand normal vitamin tablets are useless?). But you also need Ferritin (so normal Iron tablets? I thought this was dangerous to take too much iron?)

My serum results (*acknowledging the better active B12 test (which I have not had tested))

(Range in brackets)

Folate (4.6-18.7 μg/L) 4.9 ug/L

Ferritin (15-350) 86 ug/L

B12 (160-925ngL) 481 ng/L

As they were all "normal" I've never looked at these results again, until now.

I guess the key would be to get a set done with active B12 (so I know if the "normal" level about is active or non-active form of B12)



6 Replies

Hi Pete,

I personally wouldn't take folate without B12, and vice versa, they're too important as a pair. I know the article you're referring to, is it this one?

It's basically saying that correcting a folate deficiency may correct a B12 deficiency, because it has the effect of reducing inactive B12 and increasing active B12. I like the idea of it, but too often both B12 and folate are deficient together, so it is best to replace them both. I have another article about this:

So in theory, you could take lots of folate, but it might sit around doing nothing if it hasn't got any B12 to work with. So in this particular scenario, you would still be both deficient in folate (because it can't get to cellular level) and deficient in B12.

Although your B12 level looks fine, it is an unreliable test and something like the Active B12 test would be better (as you say) so it's definitely worth doing before you take any supplements. If done at St Thomas', below 25 is deficient, and you would need HydroxoB12 injections from your GP. St Thomas' recognise a grey area between 25 and 70, and they will do a further test called MMA if you fall in this box. If that is elevated then you are B12 deficient and also need injections as above.

If you come back normal on Active B12 and MMA tests, then you're B12 is probably OK (although nothing is foolproof). However, I would still recommend taking a sublingual MethylB12 supplement alongside whatever you decide to take to raise your folate levels, since they do work together. And actually a B complex is also a good idea.

Your ferritin level is not too bad at the moment. You wouldn't necessarily need to supplement iron unless it started to drop after you took the folate and B12.

Just wondered if you had an FBC done, do you have a result for MCV?



Red Cell Count of 4.85 x10^12/L (4.4->5.8)

White Cell Count of 6.15 x10^12/L (3->10)

MCV 90.3 fL (80 - 99)

Which I considered OK.

I did have some items in full blood work outside of range.

Sodium 148 nmol/L (135-145)

Bicarbonate 21 nmol/L (22-29)

Phosphate 2.19 nmol/L (0.87-1.45) **

Cholesterol 5.2




Yes MCV looks OK, but can't totally rule out B12/folate deficiency based on that because anaemia and macrocytosis don't have to be present.

High cholesterol is often present in hypothyroidism, and I think you've already established in your other question that this is a real possibility for you (you had some good answers if I remember rightly).

I can only speculate on the other things you list. Did the doctor say anything about the high phosphate result? Was your calcium or PTH checked as well? (Thinking parathyroids).

"Higher than normal levels of phosphate (hyperphosphataemia) may be due to or associated with:

Kidney failure

Hypoparathyroidism (underactive parathyroid gland)

Hypocalcaemia (abnormally low levels of calcium)

Diabetic ketoacidosis when first seen

Phosphate supplementation"

If you look up bicarbonate on labtestsonline, diabetic ketoacidosis comes up under that as well. Have you been checked for diabetes? Also of interest is Addison's Disease, did you have your cortisol checked?

Honestly, I think you should try and see a good Endo to help get to the bottom of things. Sorry I can't come up with anything more useful than that!



Thank you for your help. Yes I have had some great answers and I have been doing a lot of reading.

I do get bewildered with the amount of possibilities it's hard to know where to start.

I've been trying vitamins, diet change and nothing seems to make any difference. I even got to thinking toxic metal poisoning (causing receptor sites to be filled by the wrong metal/mineral and therefore depriving my body of the correct chemical)

Results from "BioLab"

Arsenic 57 nmol/L (<60) close

Aluminium 503 nmol (<560) close

CHROMIUM 27.2 (3.6->23.1) **** too high

I did an Iodine skin test and it dissappeared in 2 hours. But I read on web that this is a useless test now.

....again Dr said nothing was significant.

They did amit that " we give up, we don't know whats wrong"

They did send me to see a Diabetes Endo and have a synacthen test

Cortisol 524nmol/L rising to 733nmol/L after 40 mins. Pass, not Addisons.

However I thought the base level was high to begin with, but this was ignored.

I must say that after the Synacthen test I felt like the Terminator. Unstoppable 20yr old. Which I guess was the high natural steroid my body produced.

Result.... Chronic Fatigue Syndrome. ?

...and that's when I stopped going to the GP (back in April)

I've started a draft letter to Dr asking to see an Endo but am arming myself with data first.




Cortisol peaks within 30 minutes of waking, and should be in the range 500-700nmol/L, so if your base line Cortisol was taken first thing in the morning (fasting) then it's actually OK. Mine was only in the 300s, not great.

The heavy metal stuff is interesting, have you thought about seeing a Doctor of Ecological Medicine? Someone like that would be able to look at the whole picture, including thyroid, adrenals, heavy metals, nutritional deficiencies etc. I looked into doing this (as I have lots of mercury fillings) but haven't got around to seeing anyone yet. This is the website of one in my area, just to give you an idea of what they do (and also because there's lots of interesting stuff on it):



Realise that link doesn't work, here's another page from the website:


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