Underactive thyroid and Gluten free: Hi I have... - Thyroid UK

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Underactive thyroid and Gluten free



I have been diagnosed with underactive thyroid. I have no idea what this means and was given no explanation from GP except the clinical one he read from the screen twice. I’m now reading things from the internet and getting in a right muddle. One thing I would like to know is ‘What is the connection between a Gluten Free diet and U/A thyroid’. My GP gave me levothyroxine 25 mg to take once a day and go back in a month which I am doing. I have joined the British thyroid society. If anybody has any suggestions or reading material that would be useful to a completely confused tired novice in this field it would be very much appreciated.

10 Replies

The first thing to do is get a copy of your thyroid blood test results and make sure the printout includes the laboratory ranges. You need the ranges to interpret results. You can get a copy via GP reception or register online for patient access to blood tests, again via GP reception.

Always get and keep a copy of all results. Thyroid UK who are the parent organisation to this forum have lots of great information.

When you get a copy o your results then post here and we can help you understand them.

According to NHS guidelines, a starting dose of Levothyroxine should be 50 mcg unless you are very old, very, young, infirm or have a heart condition. You are likely to feel worse on 25mcg as it's not enough to replace missing hormones and just enough to knock out what you've got.

Maydy in reply to Nanaedake

Hi Nanaedake

Thanks for reply I will get a copy of results didn’t think to do that, wasn’t aware there were going to be anymore to compare with but as I read more it seems blood tests play an important part and are going to be ongoing and regular to keep track of levels. There is a huge amount of info on here that I have seen already today. And I’m 55 which I don’t class as too old just yet but I sure don’t feel it at the moment it’s awful at the moment and your right I actually do feel worse I was going to go back end of next week to GP to ask him what the hell is going on.

Thanks for your help

SlowDragonAdministrator in reply to Maydy

From NHS viewpoint , when aged over 50 the starting dose is 25mcg

NHS guidelines


That said, low dose can make you feel worse, but stick at it, get bloods retested after 6-8 weeks and dose will be increased slowly over coming months in 25mcg steps until TSH is around one and FT4 towards top of range and FT3 at least half way in range

As others have said it's extremely important to get copies of your blood test results and ranges. Keep good record of how you feel at each test and exactly what dose on etc

For full Thyroid evaluation you need TSH, FT4, FT3 plus TPO and TG thyroid antibodies and also very important to test vitamin D, folate, ferritin and B12

If antibodies are high this is Hashimoto's, (also known by medics here in UK more commonly as autoimmune thyroid disease).

About 90% of all hypothyroidism in Uk is due to Hashimoto's. Low vitamins are especially common with Hashimoto's. Food intolerances are very common too, especially gluten. So it's important to get TPO and TG thyroid antibodies tested at least once .

Link about thyroid blood tests


Link about antibodies and Hashimoto's



Hashimoto's affects the gut and leads to low stomach acid and then low vitamin levels. Low vitamin levels affect Thyroid hormone working

Poor gut function can lead leaky gut (literally holes in gut wall) this can cause food intolerances. Most common by far is gluten.

According to Izabella Wentz the Thyroid Pharmacist approx 5% with Hashimoto's are coeliac, but over 80% find gluten free diet helps significantly. Either due to direct gluten intolerance (no test available) or due to leaky gut and gluten causing molecular mimicry (see Amy Myers link)

Changing to a strictly gluten free diet may help reduce symptoms, help gut heal and slowly lower TPO antibodies

Ideally ask GP for coeliac blood test first







All thyroid tests should be done as early as possible in morning and fasting and don't take Levo in the 24 hours prior to test, delay and take straight after. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, GP will be unaware)

Maydy in reply to SlowDragon

Thank you very much SlowDragon for the information and all the links. I am very grateful for your knowledge and help. Makes me feel at ease. Thanks

Maydy in reply to SlowDragon


These are my test results

T4 12.0 pmo1/L (12.0 - 22.0)

TSH 4.27 miu/L (0.27-4.2) high

B12 840 ng/L (197-771) High

Folate 12.8 ug/L (3.9-26.8)

Ferritin 52.5 ug/L (13.0-150.0)

Anti TPO Ab 178 iu/mL (0-34) High

43G5.00 Thyroid autoantibodies 178IU/mL

I’m going to try and make sense of these with the web links you gave me. I had an awful day yesterday just so so tired I just slept most of the day which is very unlike me. But better today. Once again thanks again SlowDragon thanks for your weblinks really really useful.

SlowDragonAdministrator in reply to Maydy

So these results are, I assume, from before starting on Levothyroxine

Your FT4 was right at bottom of range. So very low.

TSH mildly raised, suggesting hypothyroid.

Bu you were fortunate that GP tested antibodies (many don't). TPO antibodies are above range confirms that you have autoimmune thyroid disease also called Hashimoto's

B12 is good. Do you supplement any B vitamins?

Folate is OK, but keep an eye on it

Ferritin Ok, but not brilliant. Eating liver or liver pate once a week, or other iron ruch food should help improve

No vitamin D test

Ask GP to test vitamin D at Thyroid retest



The aim of Levothyroxine is to increase dose slowly in 25mcg steps until TSH is around one (or just under) and FT4 is towards top of range and FT3 at least half way in range

Levo is T4 and an inactive hormone that must be converted within the body to T3

Getting vitamins optimal helps conversion of FT4 to FT3

Helpful little film


Nanaedake in reply to Maydy

Well as you're only 55 and no other health problems ask for a dose increase. Doctors don't seem to know they should start patients on 50mcg. You should retest 6 weeks after the dose increase and adjust dose and then retest in 6 week's and so on until TSH is around 1, not just anywhere in range.

Ensure you take Levothyroxine on an empty stomach and leave 1 hour before eating or drinking anything except water.

Blood tests should be first thing in the morning, fasting and take Levothyroxine after blood test, not before. This is a a patient to patient tip. Not something we discuss with doctors.

Also important to have optimal levels of B12 - Folate - Ferritin - VitD - for your thyroid hormones to work well and for you to feel good. B12 needs to be around 500 plus - Folate and Ferritin at mid-range and VitD at 100 plus .. your GP will not be aware and will declare you normal when just in range. This is why it is so important to have copies of all your results with ranges to help with posting here ...


The above website is the website of this forum and will explain everything Thyroid. Keep asking questions here and keep reading and reading 😊

Maydy in reply to Marz

Thanks Mark will do, I just happen to love reading 👍

Marz in reply to Maydy

In that case you will be well in no time 😊

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