Thyroid UK
82,699 members97,735 posts

Vitamins and minerals results

What doses do I need to be on for folic acid and ferrous fumarate and vitamin D please? I have been taking 1x 200mg ferrous fumarate once a day since 2013, 1x 5mg folic acid once a week since January and 1x 800iu vitamin D once a week since 2013. I have found it hard to increase ferrous fumarate to 3x a day as requested by GP because I get a heavy feeling in my stomach after taking it.



Serum ferritin 17 (15 - 150)

**Serum folate 2.5 (4.6 - 18.7)

**Serum vitamin B12 161 (180 - 900)

25 hydroxy vitamin D2 <6.0

25 hydroxy vitamin D3 33.1

**Total 25 OH vitamin D 33.1 (25 - 50 vitamin D deficiency. Supplementation is indicated)

5 Replies

Josie8 Bear in mind that if you do have gut issues then supplements may not be absorbed well enough, so the gut issues need to be addressed.

Serum ferritin 17 (15 - 150) - 1 x Ferrous Fumerate daily since 2013. Well, that's obviously​ not helping or your ferritin result would be a lot higher after 4 years!

Have you had a full iron panel, full blood count and haemoglobin test done to see if you have iron deficiency anaemia?

If you can't tolerate iron tablets then discuss an iron infusion with your GP.

Iron tablets should be taken with 1000 mg Vit C to aid absorption and help prevent constipation, four hours away from thyroid meds. There are various forms of Vit C if ascorbic acid doesn't suit.

Once your levels are up, you need to maintain them and the easiest way is to eat liver once a week or so.


Serum folate 2.5 (4.6 - 18.7) - 1 x 5mg folic acid

Serum vitamin B12 161 (180 - 900)

These work together. As your B12 is under range, has anything been said? Have you been tested for Pernicious Anaemia? You would be best taking these results over to the Pernicious Anaemia Society forum here on Health Unlocked for further advice, see what they say and then discuss with your GP. Something needs to be done about your B12 level not just your folate level.


Total 25 OH vitamin D 33.1 (25 - 50 vitamin D deficiency. Supplementation is indicated) - 1 x 800iu Vit D since 2013. Again, the fact that your level is still deficient should tell you that your dose is totally inadequate. Don't expect your GP to increase it though.

Just buy your own D3 softgels like these and take 10,000iu daily for 8 weeks then reduce to 5000iu daily. Retest in July. When you've reached the recommended level of 100-150nmol/L reduce to 5000iu alternate days. You may need less in the summer. You will need to supplement for life. Retest once or twice a year to stay within range, City Assays do a blood spot fingerprick test for £28

When taking D3 there are important cofactors needed

D3 aids absorption of calcium from food and K2-MK7 directs the calcium to bones and teeth where it is needed and away from arteries and soft tissues where it can be deposited and cause problems. D3 and K2 are fat soluble so should be taken with the fattiest meal of the day, D3 four hours away from thyroid meds.

Magnesium comes in different forms, check here to see which would suit you best and as it's calming it's best taken in the evening, four hours away from thyroid meds


Thanks for reply, nothing has been said about the under range B12 and I have been told I have low iron and low MCV and low MCHC from iron panel and complete blood count.


Josie8 "nothing has been said about the under range B12"

So you need to post on the Pernicious Anaemia Society forum, take their advice and discuss with your GP.

"I have low iron and low MCV and low MCHC from iron panel and complete blood count."

Low MCV means small red blood cell size.

Low MCHC means there is less haemoglobin in each cell.

Ask your GP about microcytic anaemia or iron deficiency anaemia. I don't know enough about it other than to suggest this needs discussing with your GP.


The Pernicious Anaemia Society healthUnlocked community can be found here :


I had low iron and I didn't absorb iron supplements well. I needed to take ferrous fumarate 210mg, one tablet 3 times a day, for nearly two years to get my levels up to optimal. I also took vitamin C with it - 500mg - 1000mg per pill.

What finally got me to optimal levels was going gluten free. I had already been tested and was found not to have coeliac disease. People don't have to have coeliac disease to benefit from going gluten-free, although I wouldn't recommend it unless it was essential - I can't see the point of giving up entire food groups unless I have to. But it is always worth a decent length trial for people with absorption issues.

1 like

You may also like...