Thyroid UK

Can vitamin deficiencies be the cause of weight gain?


Just wondering if deficiencies could be the cause of my weight gain? I keep seeing posts from people/pictures of people with thyroid results similar or worse than mine who haven't had the weight gain and starting to wonder if I'm just unlucky or it's just me?! Admittedly I'm only 5"1 so can't really afford any extra weight. I have an active job (physio) and always out walking with our 3 dogs but I've put on about 3 stone than where I used to naturally be over about 3 years of feeling crap.

My recent blood test shown sub-clinical hypo with antibodies: TSH 4.77 (0.27-4.2), TT4 77.2 (64.5-142), FT4 12.57 (12-22), FT3 4.96 (3.1-6.8), ATPO ABS 80.6 (<34), ATGO ABS 565.1 (<115).

GP wants to treat vit deficiencies first as thinks these are worse and more likely the cause of my symptoms:

Vit D (25 OH) 20 (<25 Deficient)

B12 238 (insufficient 140-250)

Serum Folate 8.31 (8.83-60.8)

When she asked if there could be any reason for deficiencies in my diet I felt like she looked at me and answered her own question like there couldn't be (probably in my head.) Do I just need to be strict with myself and get to the gym even when feeling so shattered or could there be a reason? I tried dieting but was just even more exhausted. I would rarely eat more than 1400-1600 calories on a normal day without trying anyway.

Thanks x

13 Replies

Unexplained weight gain is a clinical symptom of hypothyroidism, due to the fact that our metabolism has gone so low that weight increases.

Deficiencies are quite common with hypothyroidism and in other countries with a TSH of 3 you would be given a prescrition but the UK guidelines are the worst in the world in that it tells GPs not to prescribe until TSH is 10 and by that time the person could be suffering with lots of horrible symptoms.

Your FT4 12.57 (12-22), FT3 4.96 (3.1-6.8) are low, particulary FT4 (how can you convert sufficient to T3). It is T3 which is the active hormone which drives our metabolism and if low our body struggles, particularly heart and brain plus lots of clinical symptoms.

Due to your high antibodies, you have an Autoimmune Thyroid Disease called Hashimoto's. The treatment is the same and your doctor should prescribe levothyroxine. You can email louise.warvill@thyroiduk, for a copy of the Pulse Online article by Dr Toft and within you will see he recommends treatment if we have antibodies to 'nip things in the bud'.

Dieting without being on an optimum of hormone replacement is a waste of time as our metabolism is so slow our heart has to compete for energy as does our whole body. You must have by now realised GPs know little unfortunately.

Blood tests for thyroid hormones should be the eariest possible, fasting (you can drink water). If on thyroid hormone replacement you allow 24 hours between the last dose and test and take afterwards.

Levothyroxine should be taken either first thing on getting up with one full glass of water and wait about an hour before eating. Or at bedtime, as long as you've last eaten about 2.5 to 3 hours before. Food interferes with the uptake.

Always get a print-out from now on for your own records and you can post if you have a query.


Thanks Shaws,

Luckily my GP does seem willing to start a trial of Levo once my deficiencies have been addressed first but that's probably 3-6 months off yet. She said she didn't want to treat all at once as then we wouldn't know what had caused or improved what.

I was just starting to feel lazy seeing people with worse FT3 than mine who haven't had any weight gain. Was wondering if it could be to do with the deficiencies instead or just me.

Thanks again x


There's no reason not to give levothyroxine as it is lack of thyroxine which is is giving you symptoms and lower metabolism.

I think she's putting the cart before the horse if you have to wait another three to six months whilst thyroid hormones aren't being considered at all.

Many of our members are taking levo plus vitamins for deficiencies they have.

There is a reason why people who have hypothyroidism get free prescriptions for any other illnesses they may develop in future. It is a serious condition. Your TSH is just over the top of the range, whereas a healthy person's TSH is around 1, I believe.



I was wondering if she wanted to treat vitamins first whilst I still pay for my prescriptions? I don't know if that makes a difference to her?

But she did seem more concerned about possible pernicious anaemia than the thyroid since my FT3 is still within range.

I start my b12 injections in 2 weeks then go back to see her 2 weeks after when my vit d prescription runs out.

I'll ask again about levo then. I'm not the most forward person, when she said my thyroid hormones were still within range I did say but with having the antibodies it will develop to hypo and she said It was likely. She said if the supplements didn't improve my symptoms we could trial levo and also can trial levo if I wanted to try to conceive.

After the gp I had before her I'm just glad to have a dr who's eventually willing to try x


You do have a thyroid problem and this must be treated otherwise you will have difficulties absorbing nutrients especially B vitamins and iron.

Also once you start supplementing/injecting vitamin B12 the NICE guidelines state clearly any retest for vitamin B12 will give an incorrect reading so your GP needs to do the other tests to confirm if you have PA. Even then they are inaccurate and symptoms should be looked at. Many GPs are unaware of this and then wrongly tell people to stop injecting/supplementing vitamin B12 as they now have a high vitamin B12 test result.

With severely deficient vitamin D levels you shouldn't be exercising as you will do your body more damage. Your bones and muscles are actually breaking down due to your lack of vitamin D. To put it bluntly your bones are now demineralising, and if your vitamin D level goes lower you will break a finger or toe doing everyday things. So trying to do exercise particularly doing weight bearing exercise of running, weight training, resistance exercise, brisk walking etc until your vitamin D levels are near 75nmol/L is not going to help you and could lead to an injury. Again many GPs and other medical staff are unaware of this but it is all there in the literature which explains what vitamin D does in the body.

As you have a thyroid problem as well until your T3 goes up AND your vitamin levels are all optimal you should forget about doing moderate let alone intense exercise. So if you are too tired to exercise or the gentle exercise suggested hurts, leave it for a while as at some point it will suddenly not hurt and you won't feel tired.

Many NHS staff including doctors know very little about diet and exercise, so even if they treat deficiencies properly they give people the wrong advice about when they should exercise again.

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Thanks bluebug, I really wish I could stick this post to my head so people don't look at me like I'm lazy or should practice what I preach (physio)

But unfortunately also with being a physio I can't avoid loading exercise as I do it all day helping people get up and walk or with manual techniques. It does concern me how little we were taught on vitamins in our training but I guess we should be able to rely on gp's clearing these things before referring to us...

I have been telling my family I don't know how much longer I can carry on my career as I get a lot of pain in my hands and wrists especially after doing spinal manipulations or handling patients with heavy neurological deficits. But they don't really get it at 24 years old and think I'm just being silly so early on in my career. On our first day of uni we were told to accept we'd get arthritis in our thumbs and people always point out you don't see old physio's. I just thought it was normal.

It also increases my tremor which I've had for many years without dr's investigating or giving a reason. Very embarrassing when someone is relying on you to keep them upright and you're shaking like a leaf.

Thanks again x

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Your tremor might be down to low B12? Until mine was detected and I began treatment I used to be very shaky. I hope you get yours sorted soon. For some reason thyroid and Low B12 often go hand in hand. You will need your vitamins to be at good levels for your body to use the thyroid medication properly. Best wishes



Thank you. I hadn't thought about it being linked because I've had the tremor for so long. At least 5 years possibly up to 10. I thought I would have had other symptoms before or as well as that?

I suppose I've never really had a lot of energy, I'd often get home from school and sleep but I did have an issue with food and severely undereating so I put it down to this.

Would my B12 not be seriously low if it had been going on that long?

Hopefully I see a difference once starting the injections and it won't be too long before getting thyroxine :)

Thanks again x

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The levels tend to fall gradually as B12 stores are normally kept in the liver, and it can be three years of us failing to replacethem before symptoms will occur. I hope you will get things sorted soon?

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Going to the gym is likely to be one cause of your weight gain.

You are already hypothyroid, with a TSH which is over the range. In some countries it would get you treated, but sadly the NHS likes torturing their patients, sometimes for years. Although since you have positive thyroid antibody results and you have symptoms you might be able to persuade your doctor to start treating you for hypothyroidism.

You have autoimmune hypothyroidism i.e. Hashimoto's Thyroiditis. This is shown by the two different types of antibodies, TPO Ab and Tg Ab, being positive. Hypothyroidism can be caused by several different things. Hashimoto's is the commonest cause of hypothyroidism in Europe and the US. (About 90% of cases of hypothyroidism are cause by Hashi's.)

Being hypothyroid and untreated, your body won't be able to make enough T3 for your needs, or to make it quickly enough when you use it up.

Exercise uses up T3. Low levels of T3 reduce the metabolism and cause weight gain.

Your best bet is to reduce your levels of exercise and take up gentle walking, swimming, and yoga. Your weight gain and your symptoms should reduce because you will have more T3 for general, daily activity.

I wrote about what effects having Hashimoto's has on the patient on this thread earlier today :


Again, wish I could stick this post to my head for all to see before they judge...

That reply on the other post is so informative thank you. It's an answer I've been looking for and asking for a few weeks.

I was starting to feel ridiculous with my FT3 levels being normal on tests but having so many symptoms and not really reflecting my tsh or ft4 levels.

My previous test in December was TSH 5.03, FT4 14.52 and FT3 5.43 (same ranges as above)

I was SO confused how my TSH could be lower on this test but my FT4 and FT3 be lower too.

But this explains it thank you :) I don't know if this is weird but part of me just wishes it to hurry up and destroy it so I can get treated and get on because it's exhausting! x


Wow, I'm surprised you have a doctor who's keen to test the vit deficiencies, lucky you, but agree it shouldn't be before treating your thyroid but at the same time. My hypothyroid became Hashis before Christmas, many think auto immune is not reversible but many functional Medicine doctors before it can be halted if not reversed. Have a look at dr Izabella Wentz The Root Cause of Hashis (her website and emails are good, as is Dr Amy Myers. Have you been tested for rheumatoid arthritis? It is also auto immune and might be the cause of your hand pain, people with auto immune conditions are more likely to develop others

I'm studying nutrition so this is a particular area of interest for me. Many believe gluten is a trigger for autoimmune (could be causing your joint pain) as well as dairy and grains. I've been gluten free for 5 yrs and have just started to go dairy and grain free since Hashis diagnosed, but perhaps try eliminating one at a time starting with gluten as it can be quite overwhelming. When I gave up gluten (gave me excruciating headaches) I lost a stone over a year without additional effort, not just removing the cakes and biscuits but also pasta, bread etc

I personally would also not focus on calories as all calories are not created equally as they have different effects in the body, and everybody is unique in terms of their requirements. Lots of veg, some fruit, high quality protein and good fats (nuts, seeds, avocado, coconut oil) and avoid processed food and additives whenever you can, it's a real eye opener when you start reading food labels

Good luck


Thank you, I'll have a read when I get home :)

I got tested privately and took her the results so not quite so lucky unfortunately but lucky to be being started on treatment :)

Thanks again x


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