Does a lack of intrinsic factor preve... - Pernicious Anaemi...

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Does a lack of intrinsic factor prevent iron absorption?


Does a lack of intrinsic factor prevent the absorption of iron too or is it simply B12?

If so what would be the best way to get iron into the body and does anyone know of any decent iron supplements that are readily absorbed?

Thank you all for any help

39 Replies

There are (at least) three separate pathways by which we absorb iron. It appears all three can operate in parallel.

First, one works with the "mineral" iron compounds like ferrous sulphate.

Second, another works with haem (also spelled heme) such as is found in meat.

Third, yet another appears to be specific for ferritin - as might be obtained from eating liver or black pudding.

I have no clear evidence, but I suspect that taking some of each would be the most likely to restore iron levels in the shortest time.

In general, the mineral iron supplements like ferrous sulphate have absorption enhanced by taking them alongside ascorbic acid (as in vitamin C). (The non-acidic version like calcium ascorbate might not be effective - again, I do not know.)

A lot of those who cannot produce Intrinsic Factor also have limited ability to produce stomach acid. That low acid would make absorption of at least the mineral forms of iron less effective.

When supplementing with iron, it is very important to re-test as excess iron is seriously detrimental to health.

Also, iron supplements can be fatal if taken by children. Keep them out of reach and out of sight of all younger people.

Thank you a trult fantastic answer. It is greatly appreciated. I have just got some 20mg iron bisglycinate from Holland and Barrett. Is that any good?Thank you again

I'm never quite sure where to put bisglycinate - not sure if absorption is enhanced by ascorbic acid or not. But quite a lot of people prefer that to ferrous sulphate in terms of the impact on their stomachs.

A good start. Taken in smaller more frequent doses and some say every other day. It dies take time to raises iron. Retest in 3 mo ths normally

TFH1 in reply to helvella

Really appreciate you posting this valuable information - I got absolutley nowhere with ferrous sulphate and suffered unecessarily for years with anaemia. By chance a locum GP I saw said that some people did better in ferrous fumerate and prescribed it for me. It wasn't until reading your info there, that I have begun to understand why. I still have low ferritin (as does every single female in my extended family) . Should we be taking a ferritin specific supplement for this? I can't believe the lack of knowledge in the medical community on this subject.....

WorkingProgress in reply to TFH1

I am sorry to hear abiut your ordeal If yiu dont mind me asking. ..... what was your dose of ferrous fumerate? I take it that does not represent ferritin levels then.

helvella in reply to TFH1

I am absolutely NO expert.

The reason for taking a ferritin product (that is, one which contains ferritin - there are very few of them) seems to me primarily to allow exploitation of a third pathway.

Other than that, I think haem sources make sense - possibly along with one of the chelated forms.

Yes lots of meats liver etc and chelated are readily available. Just didn't want to over do it with supplements so hopefully 30gm chelated each day should be ok. That's my thinking. Any ideas as to that dose? Kindest regards.

My thought is that what really matters is how your iron levels change - not how much you take.

Regular testing is essential. And, I'd very much hope, not just ferritin but what is sometimes called a full iron panel.

TFH1 in reply to helvella

I take 210g ferrous fumerate daily (approximately 69mg of elemental iron)

WorkingProgress in reply to TFH1

Wow. Elemental iron? Meaning just.... Correct? How long have you been taking that dose has it helped? Mine just says ferrous bisglycinate iron 20mg. But I have a vitamin patch with 11 grams in it too.

TFH1 in reply to WorkingProgress

I've been taking that daily for about 14 years. As I mentioned to the person who originally asked the question, the missing part of the jigsaw for me was improving my microbiome by taking homemade kefir daily. For the first time in my life (I'm 47) I feel healthy. Digestion has improved beyond recognition and iron blood tests show around the 13 mark. I'm not sure what my ferritin is now as frustratingly nurse neglected to request that one last time bloods were done, but typically it hovers around 9 or 10, so still very low. Am ordering the ferritin supplement you mentioned for myself and my daughters as we speak...

WorkingProgress in reply to TFH1

Good digestion is key. That too is why I am Working on. Now I have got to find a company that does a decent full comprehensive iron blood panel and not just ferritin

WorkingProgress in reply to TFH1

Did your doctor start you off on more than one per day of ferrous fumerate? If so for how long?

TFH1 in reply to WorkingProgress

Hmmmh tbh can't remember, but habe have always just stuck to one per day.

WorkingProgress in reply to TFH1

Got it. That's still 40mg more powerful than mine. So I know j can up mine if need be but mine which is from Holland and Barrat does make me drowsy. Ferrous bisglycinate. Maybe there's another form that won't. Did yours make you drowsy and was your stool affected?

TFH1 in reply to WorkingProgress

I have never noticed drowsiness and definitely darker stool but nothing ridiculous and no constipation or belly ache.

TFH1 in reply to WorkingProgress

BTW on doctor's sticker it says 1 or 2 per day

WorkingProgress in reply to TFH1

Thank you. Greatly appreciated.

Gambit62Administrator in reply to TFH1

TFHI - image removed as contained name of dispensing pharmacist

TFH1 in reply to helvella

I hear what you're saying about being NO expert - however you've looked into it more deeply and explained the situation more clearly than any GP or medical professional I've ever spoken to and also managed to find information that has eluded me, so very interested in your opinion!

TFH1 in reply to helvella

I am sitting here slightly fuming that I have suffered for DECADES with chronically low ferrtitin, have sat in endless consulations with GP's and specialists and not a single one has mentioned that there is such a thing as a ferritin specific supplement!! Words fail me at this point.

helvella in reply to TFH1

This is the only one I know - not meant to push you towards any product or supplier:

I cannot say it works better than haem supplements - just that it is different!

No. IF is only involved with the absorption of B12.

However, if you have no IF because of PA then it means that you also have low stomach acid. In PA the immune system attacks the parietal cells in the stomach. These cells make IF and hydrochloric acid.

To be absorbed, iron needs to be in solution. And the more acidic the environment, the easier it is for iron to dissolve. Which means that people with PA will have difficulty absorbing iron.

The other way for iron to get into solution is for it to be chelated - surrounded by one, or more, organic chemicals. The best form of iron is haem iron, where a molecule of haem (yes, as found in haemoglobin) surrounds the iron atoms. This form of iron is found in red meat and offal, making that the best way to get iron naturally.

Iron supplements can come ready-chelated. Bisglycinate, fumarate, gluconate, are all forms of ready-chelated iron that should be easy to absorb.

Doctors like to prescribe iron sulfate. This is the worst form of iron supplement. You can help it be absorbed if you take the tablets with citric acid and ascorbic acid. Both will act as chelating agents. Effervescent vitamin C (ascorbic acid) tablets are a great way of helping iron sulfate to be absorbed.

I like to take haem iron as often as possible, but it's not easy as I'm the only carnivore in the house. So I also take Iron Bisglycinate (Solgar Gentle Iron) 20 mg every other day.

Be wary of taking too much iron, as it can be harmful in large amounts.

Thank you I have just got ferrous bisglycinate 20mg from Holland and Barrett. Hopefully this will be ok? It's called gentle iron.

Do I take my iron suppmement....ferrous bisglycinate with or without food? I have plenty of Vit C ascorbic acid which is good. Does it matter what time of the day I take it?Thank you again.

Your iron is already chelated, so no need to take with vitamin C.

The Gentle Iron bottle should include directions. Mine says to preferably take at mealtimes.

Hi fbirder.. sorry to bug again. I am microcytic (thallassaemia trait)with declining b12 over the years. My ferritin was 13.4 despite feeling like death raised heartbeat and still bedridden with zero energy. As you can imagine my GP says theres no problems. I do have sibo too. So a sorotion may be lessened. Would 30g iron bisycinate each day be too much iron to supplement that safe? I hear of extreme doses that Gp's prescribe of that nasty poorly absorbed prescription iron. Thanks again for your help.

Kindest regards.

30 grams would definitely be too much.

30 mg shouldn't be too much, but ask your GP first.

Sorry yes 30mg. My GP is doing nothing even tbough i am laid up in bed its up to me. The practice unfortunately has such a bad reputation. My b12 should be up by now and still chronically fatigued so it's all pointing to low iron. Had bloods done but they only do useless ferritin and nothing else. There are many who are on ferrous fumerate 210mg 69mg iron 1 to 3 times daily. So I think I was over worrying little as surely I can up the doses safely for a while to gauge the results. Say 20mg bisglycinate ×3 per day.

There may be many who take a lot of iron, but they aren't you.

Please ask the doc if 60 mg of iron a day is OK. He might well tell you that you don't need it. Just ask him if it will be harmful.

I will have my bloods taken next week privately and can adjust from there. My GP service is useless. They have a terrible reputation plus their tests are pointlessly poor and awful. They just measure ferritin and if you ask for a full iron panel they blank refuse and hang up. So frustrating

Change your Gp.even within same practice. Sounds appalling full bloods not done. I ask.

Ask what is a safe amount for you.

I was started on a high doses I xouldnt tolerate.

Now take 210 ferrous fumerate every other day and alternate with spartone and 20mg gentle solgar iron

I'm now finding a maintenance dose so trying ferrous fumerate every third day.

It took a year.

Doctor was happy with HB stabilising and other iron results

Ferritin takes time and everyone operates af a different level so such a big range.

Insist for a full iron panel. Any Gp should

do that.

I asked for ferritin because if specific symptoms .

Also had one previous reading giving an indication what is about right for me .

If Gp awkward .

Ask what they woukd suggest is safe

Ask for advise.

Do retest

Again Gps will if they condone /agree with supplement

Best to try and work with a Gp.

All recorded on your medical notes.

Theg can refer and open doors .

Iron is complex.

Like so many supplements smaller doses better more frequently if needed for absorbtion.

These are only my thoughts and I'm no posture of health ad an example.

Bloods are important to monitor.

Obviously food the best source if yih find ways to absorb more.

T c

DRunnerchick in reply to fbirder

fbirder- this has been so helpful to me. I’m fighting non-anemic iron deficiency. My Hb went from 14.2 to 11.2 in two months (idiopathic) and my ferritin was 4. I was a regular blood donor due to rare type and donated on the regular with my Hb staying in the 14s until the drop in November.

I’ve been on Hemi-Plex supplements (chelated iron w/ Bs,C, etc for absorption) for 2 months. Hb is now 12.1 but ferritin is still only 10. I have Stiff Person Syndrome which usually travels with PA. So far I don’t have PA but on several occasions I have had very low B12 so now supplement with sublingual which seems to work best for me.

This latest could be new autoimmune change but your explanation of absorption routes is so helpful to me and explains why ferrous gluconate never worked for me. I have had a 1000mg infusion in the past for IDA.🤷‍♀️

I used to be a long distance runner and extreme sports person so it was assumed it was due to high mileage (foot strike anemia) that is obviously not the case now since my body refuses to move in an upright mannner without coaxing and lots of yoga these days 😣

Doc wants me on Hema-Plex for another 3 weeks before we resort to another infusion.


What is your digestion like? If your digestion is poor generally this obviously won't help. Do you react badly to gluten / have you been tested for coeliac disease? I have both coeliac and PA - if you have coeliac and continue to eat gluten, the villi (which are small finger like projections in the intestine which absorb nutrients incl iron and b12) get flattened and cannot perform their function correctly so the b12 and iron problems go hand in hand.

After many years I solved my iron problem with a 3 pronged approach 1) Stopped eating gluten (I'm coleliac so this one not relevant unless you get diarrhoea after eating foods containing gluten such as bread and pasta) 2) Started taking ferrous fumerate daily instead of ferrous sulphate 3) Addressed my overall poor digestion by drastically improving my microbiome by drinking homemade kefir daily - it's cheap, easy and packed with beneficial probiotics. Feel free to message me if you want more info about this, also have spare kefir grains I can post,

WorkingProgress in reply to TFH1

Thank you. I do not take gluten and am Working on the gut slowly with quality herbs,probiotics and enzymes from naturopatb. Also cultured foods etc. There's is very slow but gradual improvement there but as mentioned I am microcytic and my ferritin was 13.4 b12 was 196 with supplements. I have had about 24 shots of hydroxy in the last 30 days and still cant really get out of bed.

Its going to be a slow process. So I was just wondering if all those shots lower iron or would 30g ferrous bisglycinate be ok each day on top as well as the usual b complex.

Thanks again.

Gp's fob people off...figuring out health problems is really tough.


Photo of back of ferrous fumerate box showing dosage

I'm also taking cultured foods such as sauerkraut and kimchi, but the homemade kefir was the real gamechanger for me. Good luck wth it and hope some of the excellent replies in this thread were of help. I learned a lot too!

WorkingProgress in reply to TFH1

Thank you. It is all helpful. There are some incredibly educated and knowledgeable people here such as fbirdir. He really knows his stuff.

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