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Thyroid UK
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Gluten Free diet skew test results?

Can anyone tell me - does a Gluten Free diet skew blood test results for the antibodies tested to check for Hashimoto's?

21 Replies

Well it could. Not quite sure on this but the molecular structure of gluten/gliadin is very close to thyroid tissue. So if you remove the gluten any antibodies to that won't mistakenly attack your thyroid. Something like that at any rate.

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Thanks Posh, Do you think two weeks before the appointment would be a reasonable time to come off the gluten free diet in order to get an accurate reading?


After 4 years as a hypothyroid on levo my health went down hill. Eventually discovered i had raised TPO antibodies.Read a lot and decided to go gluten free. Next antibody test result was much lower but still positive for TPO. Then also went dairy free and next test was almost zero. Took about a year to reduce. Felt a lot better.

Recently did a Blue horizon test and for the first time I wa tested for tgab antibdies. They are present but within the lab range, so in other words I do have them but at a low level.

So if you have TPO above the range I would try Glutne free diet.

Not sure of the implications of tgab, not had time to research!

Hope you can decide if you want to go GF and if you do that it helps you too.


Thanks Crimple, I will definitely try GF, but I don't want to be on a GF diet at the time of the tests if that is likely to skew the test results. It would be a shame to not get an accurate diagnosis first, do you think 2 weeks would be long enough to off the diet before the tests?


People report that their antibody levels fell after going GF so I think the answer is yes. The test measures the presence of antibodies, and gluten in the diet makes some people produce more antibodies. I am not sure the word skew is the right choice. If gluten is aggravating your symptoms a GF blood test is really the true reading.

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Thanks Ruthi, I due to see an Endo for the first time because my GP is unable to request the tests needed to determine a diagnosis. I am hoping to find out what my problem is and I have only just begun a Paleo diet which is GF. It is probably too early to say if I am finding any benefit from it, and I really want to find out what is going on. I am hoping to get my antibodies tested to see if it Hashimoto's for one thing - as I believe it probably is Hashi's and wouldn't want the diet to stop diagnosis. Do you think coming off the diet for a fortnight before the Hospital appointment would be long enough to get an accurate test result?


I believe the effects of gluten in the diet can affect the gut for upto 6 months even a year. Blue Horizon can do a blood test (DIY) which gives full thyroid profile and both antibody tests. Cost me £80 and got the results by email within the week. Have a look on TUK website for details or look on right hand side of this page under related posts.

good luck


Thanks, I will bear this in mind if the Endo doesn't check all those when I get my appointment.



Once you have thyroid antibodies you have them for life ... just in varying degrees.

If a gluten free diet has helped to lower the level and so make you feel better (and thyroid meds work better) it is imperative to stick with it.

You will get a Hashimotos diagnosis whether your antibody levels are high or low as long as they are out of range.

If you eat gluten just to get a high antibody test result it could cause inflammation in your body that may take many months (or years) to reduce.

Some do eventually mange to reduce their thyroid antibody levels low. I have not & certainly wouldn't chance raising them as they are very destructive to the body.



Disclaimer: I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


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Thanks flower, I have only just started the Paleo diet which is GF but so far cannot say I feel any benefit but it is probably too soon to say. Therefore I could easily postpone this diet until after the consultation, do you agree?


Hi, I've been totally gf since September and I had bloods done in early December I had bloods done in June and my Decenber thyroid results were very similar to what they had been in June - but my antibodies were massively reduced.

One (can't remember which offhand) which had been flagged up red print was well with the range, the other which was also flagged in red was still in red but was half of what it had been previously so going gf seemed to have made a difference to my antibodies although it didn't alter my thyroid results (TSH, T3, T4 ) at all.

I don't know if that would happen for everyone though or if it was just me.

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Thanks Fruitandnutcase - would you think it would be worth waiting until after the appointment before going GF to get an accurate test result or maybe just adding a Weetabix for breakfast for the 2 weeks prior to the appointment? I don't want to spoil my chances of a proper diagnosis after all the difficulty I have had to get tests done!


I'm not medically qualified but I've got a feeling that if you are going to be tested for a gluten allergy 'they' like you to be eating gluten for a while before you are tested. I don't know how long or how much though, as you say you want to get it right after all the effort you have put in to be tested.

There is another group on HU called GlutenFreeGuerillas - why don't you sign up to that and ask them what they think? Someone there will be bound to be able to help you.

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Hi there it is not a gluten allergy I am hoping to be tested for - it is a test for antibodies to diagnose or rule out Hashimoto's, so I don't think the GlutenFreeGuerillas would be relevant. But, thanks for replying.


Interesting question. I recall I read to go GF and hadn't tested for gluten intolerance/sensitivity - which part of me wanted to know...

SOOOOO I think what you are wanting to know about the Hashimotos is similar thinking - but in the end, I decided that all the advice was leaning towards GF - and I have to say I found it hard, as my diet had always been...fill up with bread...cake...biscuits..cereal etc and I would love to still have those gluten items for ease.

If I put my view across (that is all it is) - that if you are presently GF and you stay that way and go and be tested - and it comes up with 'TPO' antibodies, you can guess that either they MIGHT have been higher when you were on gluten and come down - or they might be unrelated and you will find out what level - but you just wont know if you can put it down to gluten / gluten free, so it depends if you just want to stay off those gluten foods, as much advice says so and try to forget whether it raises antibodies or not...

OR if you want to consume gluten foods - likely for ease and they can taste better etc, giving more options and by being tested OFF them - you think you wont know if antibodies will shoot up if you reintroduce gluten foods later.... I feel you will likely have more tests periodically, with these conditions anyway -

HERE I CLARIFY MY VIEW - the score you get whilst OFF gluten SHOULD show what antibodies are present at time of test - if you have been OFF gluten for some time and you still have high or out of range antibodies, you can say it is likely Hashimotos but you will know that you have them whilst off gluten, so in a way you would be getting a clearer view. That may sound funny, but when people blame gluten / gliadin, it is supposedly a leaky gut whereby the gliadin has done some damage and so proteins deemed and toxins enter thru gut wall into bloodstream - and hence get attacked and likewise, as they say gliadin is similar to thyroid, the gland gets attacked. This is still going round my mind, as a little weird... how can one gliadin / protein be the same as thyroid / tissue - but this is how we muddle through not knowing what is right or wrong.

I would say decide on whether you are going to stay GF for duration or life. Some might say once leaky gut healed you can go back on gluten...or any other food that is deemed a trigger.

Get tested, see what all levels are at - keep working at the diet with foods eliminated - maybe - and try to accept all this is never clear, some cut dairy....then sugar... and so on, but I haven't yet been retested after going gluten free (alone) so I am wondering if my antibodies have gone down - LOL! BUT I am a bit anti docs at the mo - my TSH levels were seriously dangerous and I had issues with the medication (T4) - so started working on diet, not properly don't think YET - but you see where I am coming from, I DO want to think GF has lowered my antibodies and would love to cure self via diet changes etc. I am resisting gluten / wheat etc but know there are some foods with hidden gluten in etc - once realised, you know you have to give longer to claim GF.

It is rare to if ever heal enough (cant say cure) but some defo report lower antibodies from GF - but every person is different!!!!

What is true is IF you take some gluten - ( some will say you DO need to have never come off it) - I believe back on needs to be 6 months (maybe 3) - however you could cause a worse reaction going back on it (or not) but it will likely take 6 months to a year to come back out of system once again - so is it worth it? You wont know that the reading hasn't shot up after one day of gluten or how sensitive or if at all - by consuming - unless you have a first reading to compare to. So testing whilst off it - shows pretty much a true picture, as of now.

Imagine if you get a test and you find low or in range antibodies - that is actually a good outcome.

If you have zilch near enough - you know roughly where you are at and can be thankful.

If you have horrendously high and you have been totally GF (including hidden and traces in food) for some time... whilst it is despair - you will know that it isn't gluten that has raised them - so next plan.... whatever you are advised or decide etc....

I have babbled on enough here (and note I am not always on here to enter reply / conversation - I just wanted to help - haha - by just saying we do feel we need clarity but nothing is solid. Hope that helps you decide. I would stay off gluten - get tested - and bury head about the being tested on gluten - at this time, keep working to get levels as good as can - decide on future tests, if over even longer period the scores have improved and you THINK it is down to diet etc. If like me - I get close to thinking blow it, I feel so ill...will eat what want but I have to tell self to keep reading... keep trying all suggestions... one at a time here...but still - will I cut dairy and sugar....(nowt left to eat springs to mind LOL) - I ought to, but again I want to know of GF has helped. :-)


Hi Storm, my main aim at this moment is to find out if I have Hashimoto's, and since it has taken such a lot of effort to be referred to the Endo, I don't want to scupper my chance of getting a clear diagnosis for the sake of postponing going GF for a few weeks. If I am diagnosed as having antibodies and therefore having Hashimoto's then I will try going GF, but it does seem quite difficult to do and if I don't have antibodies then there doesn't appear to be a need to put myself through it. I have started a Paleo diet to try to lose some weight, as I have put a lot of unexplained weight on, but have decided to add Weetabix for breakfast until the tests are done so that I don't skew the tests. Thanks for your reply and hope you find help using your diet - I admire your willpower!


Hiya - ah, it sounded like you HAD already been GF for some time and was going back on, just to be tested, which if you'd suddenly reintroduced gluten whilst you could have fast reactions - it might or might not get any related antibodies up to how high they might go staying on it.

It definitely is NOT easy, as you realise you so depend on the very foods for everyday living - but in my case, I couldn't take T4, docs wont prescribe NDT / Armour etc, I cant travel to see any private doc up the country and I was suggested to see an endo for T3 as doc wont prescribe that - and I am a bug wuss re tests, though I have had several - haha - but wanted to try to see if could help self naturally (against the odds)!!

I do see your point, but generally 'they' say don't come off gluten at all until tested (mainly applies to testing for allergy as not all tests reveal a person that is merely sensitive) but for what you want to find out - some people do the other thing of coming off for three months, then retrying to see if they feel side effects.

How does all this relate to you wanting to find out if Hashi? You would find out about antibodies on or off gluten if they are present but before I came off gluten (as I don't know score now) my first antibodies was low but above range, lets say it was about 200 - by the next test, within months it was suddenly a whopping 2500 and I cant pinpoint it to anything specific. Likewise on my next test (when brave lol) if those antibodies have gone down, I will presume it is my diet change - but then it might be because I have tried to add in vit tablets invariably on and off or cut some other trigger - I wont know for sure - see :-)

Hope you DONT have antibodies - that would be nice - you can still get them later - but it would give you a chance without being under attack. :-)

Take care.


Hi Storm, I had tried a Paleo diet for a couple of days when the GP referred me to the Hospital - I understand the Paleo is pretty much GF, but I was trying it solely for the purpose of weight loss. Previously I had one test for antibodies and it came back as 28 where the lab range for it was >30 so was told it was negative, I asked them to test for TgAB but was told it was not given because the other one indicated it was not Hashimoto's but I have since heard that you can be negative in one and have antibodies in the other. I am hoping to get the test done by the Endo as I think my symptoms point towards Hashi's. Maybe you have thoughts on having a blood test result of 28 in a range of > 30 being indicative of Hashimoto's? Thanks in anticipation x


I am no expert, although I suffer, so that is first hand in my OWN matters haha - but as I understand it, you can have a very low amount of antibodies, as opposed to a zero reading, which is normal. Mind you I would wonder about that too! But I was told once, that a level say 10 would be just a base (I cant recall what those small antibodies relate to - something else in the body, for which you may have them - I think, but don't hold me to that).

Re: levels set by these so called professionals - it is all very well, but they sometimes stop there..... and you need to battle to get retested some months down the line.

So the most used test of TPOab is pretty much a clue to auto immune or Hashi likely - but they wont label it unless, so I am told... you have inflammation in the body etc -

This just shows what a long ole row I had with docs, as they merely said hypothyroid - tablets for life!! I am still fuming - as if they had checked for antibodies in first place, I may not have got as bad as I did - BIG IF.... had I known as much as do today (which is still confuzzled, like many, we don't have much to go on that is 100% fact) - but say I would have likely changed diet etc. Funny how I even said to docs what about lack of iodine - nope - tablets for life - NOW... see if you read and see you need to be careful with iodine, but you need selenium and selenium is said to lower antibodies - but you cant just take random selenium - all has to be carefully balanced etc - espec if lacking in iodine, good heavens...yet the body needs iodine for other things too...

It is all maybes - but just maybe I was lacking in vits, minerals etc which turned to body under par.... lots of stress.... so many factors, that all led to auto immune.

I would be working on what I have read and what little scientific evidence MIGHT be true out there... and put the whole thing together and worked out what may be the root cause (there is a good book out there and online, social media etc - which gives vague explanations on so many aspects of thyroid / Hashi - 'The Root Cause' and whilst too tired to read books word for word etc.... it instilled some deeper thinking - outside of what docs say).

I appreciate you are going down the proper route - endo etc and I hope you have a great one, that knows their stuff but also lets you know.

My view is really that we are all muddling along, not knowing the correct facts - not being told - and so we try this, that and other... process of elimination - it is not one simple thing.

With a low antibody score - I would be inclined to put a LOT of effort in to trying to rid those - just keep open minded, that NHS tend NOT to seek root causes and that influences what they tell you :D

I do wish you luck and every success.


Thanks Storm, do you think having the test result of 28 indicates Hashi's? I don't really plan to rely solely on diet to make me feel better, but rather tablets AND diet depending on if it is Hashi's. My symptoms are brain fog, anxiety + depression, lack of libido, lethargy, heel pain, loss of both eyebrows and eyelashes on the outer edge, loss of body hair on arms and legs (and pubic eek) and last but by no means least of the problems is the unexplained weight gain of 3 or 4 stones. My symptoms were all improving (but not totally gone ofcourse) then my TSH became suppressed and the GP lowered my dose of Levo and now they are back. I just hope I get an Endo who at least knows the rudimentary of Thyroid/Hashimoto problems and gets to the root cause which would enable me to get the best treatment.


I know all this is horrendous, I'm four years since diagnosed with hypo - yet that was Hashi, just they didn't discover it - but twenty odd years ill altogether, whereby they suggested I had M.E. but variable levels of agoraphobia - which, after twenty odd years could easily be related to auto immune / Hashi, thyroid - charming nobody thought about that! :-)

Indeed it IS advised to take the meds and work on the rest - the only reason with me - is I was on T4 / Levo and body rejected it - and I asked for NDT / Armour and Doc wont give it - hence suggested hospital / endo to see if T3 is possible - but I am terrified of that - however loads upon loads of people have a bit of T3 added to T4 and say it is one of the best things they did - each person different.

This site has so many experienced persons, that either know first hand what MIGHT help or they are well read.

I had many of those symptoms and I still have some, as I am being realistic, I doubt when I next brave tests I will be much better by scores - BUT say with hair loss - it is sometimes recommended to get iron in the body say via eating liver (sorry, I know yuck) - but it can be the meds too. You may need vit C to help absorb that iron. It isn't recommended to take iron supplements but some take that Spa tone.... without too many bad side effects - but again I'm not a doc, so cant advise - just merely suggest reading about that. I had cardigans and bedding and furniture covered in hair.

Now, when I first stopped bread, I lost about a stone and half very fast - it started off near a pound a day - EEK... but that lasted some time, say the weight stayed off for maybe year and half - but I missed the bread, cake biscuit...cereal..(wheat) but I cut other grain somewhat too. I then wanted to fill up with sugar - oh dear and whilst I know wrong....chocolate crept in.... YET OH NOOO... soya...another likely no no.... and that is in many things..including the choc I was eating. Fatigue doesn't make you want to cook - BUT I am mainly meat and veg - fruit - dairy still.... but will review that in time... but my weight is still higher than should be, by couple of stone, likely fluid!

I started taking multi vits and they vary - I really need to do things better on that score - I found I couldn't take ACE + SELENIUM after one single tablet, my eyes went all funny.... I thought I was a gonna... LOL.. but then I moved on to say 2 or three brazil nuts for selenium, not daily mind...as I find it hard to keep wanting and not sure on whether was working or not, some people are sensitive - but then my scores got worse - and I didn't get tested or rather should I say I did private test for Iodine which showed as under range... hmmm... then they say don't just take iodine, should be enough in food - brain overload says well..if lacking....surely....?!! BUT it can be dangerous and it IS in levo -

I didn't learn you need iron and ferritin & folate, B12, Vit D3 (possibly a little K2 with the D3 thing - another warning, careful) and all that - which if lacking could make the T4 not convert to T3 and so on....

Who would know that if docs test anaemia and say not - that actually you need ferritin tested and so on....blimey....

Seriously though, check out Izabella Wentz (something like that - book and online and FB) cant put links but whether true or not - it gives some HINTS of what to look into further - as long as don't believe all the hype.... it is very rare to be 'cured' but some do get a bit better.

I wish 'they' would put a cure out there.... too easy to keep people on meds for life - they forget we want answers.

Best wishes - no need to reply again - will leave it with you - take care! :-)

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