Thyroid UK
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Advice please on results for vitamins/minerals and supplements

Further to my first post for thyroid here are results for vitamins and minerals. I was diagnosed with iron deficiency/microcytic anaemia and doctor refused to let me supplement iron until 2014 and I have had an iron panel done recently but no idea what it says. I was also diagnosed folate deficient in 2014 but after folate levels came back into normal range they have become deficient again and doctor started me on folic acid. Complete blood tests have shown I have low MCV and high MCHC. I have also been prescribed vitamin D3 800iu tablets on and off. Doctor restarted my vitamin D last month. I feel awful with these symptoms - periods flooding through clothes, daytime tiredness, dry skin all over my legs, hard stools, preference for heat, shaky arms and legs, grit coming from eyes, feeling low and irritable.

Thank you.

*Serum ferritin - 10 (15 - 150) ferrous fumarate 200mg once a day

*Serum folate - 3.4 (4.6 - 18.7) folic acid 5mg once a day

*Serum vitamin B12 - 157 (180 - 900)

*Total 25 OH vitamin D - 30.8

(<25 severe vitamin D deficiency. Patient may require pharmacological preparations

25 - 50 vitamin D deficiency. Supplementation is indicated

50 - 75 vitamin D may be suboptimal, and long-term may lead to clinical effects. Advise on safe sun exposure and diet. Supplementation may be indicated

>75 adequate vitamin D) vitamin D3 800iu once a day

6 Replies

I am not good at blood tests and others will respond, but what surprised me is that your B12 is so seriously low (below range) that your doctor hasn't tested for the intrinsic factor which would mean you have pernicious anaemia and by giving you folic acid can mask a deficiency as it changes how our blood cells appear when examined.

B12 and Vitamin D are both prohormones, not just vitamins and are necessary to be optimum. With too low a B12, the aim is towards the upper end of 900 to 1,000 as we could develop dementia or alzeimers disease.

I'd phone and speak to your doctor and ask for an intrinsic factor test but I think if you pop over to the Pernicious Anaemia forum, they will advise how best to be diagnosed.

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Yes, I would also really suggest testing for intrinsic factor too in order to rule out pernicious aneamia as iron aneamia will also hide PA like the folate as will make the MCV smaller. Either way, your b12 is far too low which is not good and if the intrinsic factor test comes back showing normal, you will need to figure out why all your levels are so low.

If you have a balanced healthy diet and are eating enough of everything, then you may be having absorbtion issues. You will need to rule out issues such as coeliac disease and other stomach issues that can cause malabsorbtion especially since you note having issues with your digestive system. Even if you have already had a blood test for coeliac, these are often false negative and only biopsy can determine whether you do or don't. Even if this comes back negative, you may still want to give gluten free a go as this can lower antibodies and help with autoimunity and reduce ibs etc. I now have NHS diagnosis of Non-coeliac gluten sensitivity as I test negative for coeliac but has been proven that gluten causes autoimmunity and absorption issues in me and my daughter. Failing that, you could try a six week elimination diet to see if anything else bothers your stomach.

I don't know about other stomach issues that could have the same effect so maybe others can offer other suggestions?

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Vitamin B12 and folate ask on the Pernicious anaemia society on healthunlocked what you should do and then ensure your GP does it.

Ferritin if possible up your dose of iron to 2 tablets a day, at different times of the day. Obviously take 4 hours away from levo, 2 hours away from other food, drink and supplements. Take with vitamin C and water. You want your ferritin level at the lowest 70 but preferably 80.

You need to get your ferritin level tested after every packet of iron tablets to check where it is.


Vitamin D take 5,000IU per day for 12 weeks then go down to 5,000IU every other day.

Take vitamin D with cofactors magnesium and vitamin K2-MK7. Take the vitamin D with the fattest meal of the day. The co-factors don't have to be taken at the same time as some people prefer to take their magnesium in the evening. However if you taking iron in the night or levo you can't do this.

In May retest your level you are aiming for 100nmol/L. You can use City Assays as it is unlikely your GP will retest you at your level.


Finally for both vitamin D and ferritin you will need to take maintenance doses for the rest of your life once your level is within the defined parameters.

Recommended for vitamin D is 1,000-2,000IU per day. Unfortunately you won't know how much you need it is a bit of guess work. Regardless you will need to test your vitamin D levels yearly in October. Many NHS areas refuse to allow people to have vitamin D blood tests unless they are showing symptoms of fatigue, illness etc or only once every two years, so again you may need to use City Assays to do private testing.

For ferritin if you are post-menopausal you should be able to keep your ferritin up by eating liver twice a week. If you are vegan, vegetarian or pre-menopausal you will need to take iron supplements. The amount you need to take depends on your periods and you in general. Some people find 2-3 ferrous fumerate a week is enough while others need ferrous fumerate/ferrous sulphate/ferrous gluconate every day. Again you will need to monitor the level and it is dependent on your GP whether they will do this for you. If you had difficulty raising the level you want this done a minimum of every 6 months initially.


*Serum ferritin - 10 (15 - 150) ferrous fumarate 200mg once a day

That dose of ferrous fumarate is too low for someone with below range ferritin. With your level being so low you really ought to have iron infusions. It is going to take a long time to raise your ferritin levels with just tablets.

Ask your doctor for iron infusions, but don't be surprised if he/she says no.

I had low ferritin and I was briefly prescribed ferrous fumarate 210mg, one tablet, three times a day, which is the highest dose people should take. Then I started buying my own. They come in boxes of 84 which is enough for 3 tablets a day for 28 days.

I've taken both of these brands in the past - the first link is the one I was prescribed :


In the UK ferrous fumarate 210mg and other high dose iron supplements are available without prescription, but only from pharmacies, and then only at the pharmacist's discretion. Boots can be awkward, but I've got iron tablets from Lloyd's Pharmacy and Tesco Pharmacy without any difficulty. If I'm asked I just say I was tested recently and my iron is low.

I forgot to say - high dose iron supplements can be bought online too.

A very helpful document written by helvella, one of the admins here :

If you eat meat, then you could speed up increasing your ferritin and iron levels by eating liver and/or black pudding once or twice a week.

With every dose of iron you should also take 500mg - 1000mg Vitamin C. This helps the body to absorb iron. Supplementing iron causes constipation in some people. Vitamin C, in high enough doses, causes diarrhoea. You need to adjust the dose of vitamin C to keep things moving comfortably.

It took me nearly 2 years to raise my iron and ferritin to optimal. But some people absorb iron much faster, and can repair a deficiency in 6 months. Since iron is poisonous in overdose it is important to test regularly - say, every 3 months. There is a finger-prick test you can buy online which is worth doing if your doctor won't test for you :

With a reference range of 15 - 150 for ferritin, you need an absolute minimum of 70 for your body to be able to use thyroid hormones adequately. Ideally you will get your level to 80 - 100. Some people like it to be as high as 120, but I wouldn't suggest going any higher that that.

Incidentally, low iron is a common cause of very heavy periods. And very heavy periods are a common cause of iron deficiency. It's a vicious circle. Getting your iron levels up will help. But since your levels have dropped so low you will almost certainly have to take iron indefinitely (or at least until menopause, and you might need to continue after that). Once you have got your levels up to optimal you would reduce to a maintenance dose of 1 tablet a day - but that could be some time away.


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