Can low blood sugar be an issue in an underacti... - Thyroid UK

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Can low blood sugar be an issue in an underactive Thyroid? Do you know what your HBA 1c number is?

ukred profile image

Forever on the quest to find out what can be wrong with me. Loads of symptoms last year led me to believe it may be my thyroid. GP gave me antidepressants. So I eventually gave in to them. In March last year my TSH was 1.37. (NHS). My Feb this year it was 3.57. (NHS). All other thyroid bloods in range. I also had a medichecks one done at the same time -that was 4.7. At the start of May as it was 4.4, the medichecks doctor suggested I contact the GP. I wrote to them explaining everything and sending my blood tests.. They offered a telephone appt.

I managed to get a face to face appointment last week because I felt like my throat was swollen. Anyway, after she had examined me, she sat me down and told me she thinks it's water retention. She thinks all the aching, swollen puffy face, dry skin, hair loss etc etc....may be caused by the antidepressants she gave me.....I despair. She wouldn't even discuss the medichecks blood tests, just telling me I was in range...

Between Feb and May I chucked all kinds of vitamins and minerals at myself and my May blood test showed I had improved them so I don't think that's the cause. I have started a very slow reduction off the antidepressants but that will take ages.

At a loss, I was looking through my NHS blood tests and I noticed two things. BOTH tests showed raised cholestrol (I eat very little fat and am vegan). Both showed a low HBA 1c level - 34 then 33. It says 40 and above is 'normal' and this started me thinking. I have a dip in the middle of the day and often feel I really have to eat something. Could part of my symptoms be something to do with my sugar being too low? The 34 was taken when I had lost two stone and wasn't eating but the 33 is recent and I've put it back on and then some (antidepressants) and am eating normally now.

Does anybody know their levels please?

30 Replies
SlowDragon profile image

As a vegan you will need to supplement regularly

Essential to regularly retest vitamin D, folate, ferritin and B12

What vitamin supplements are you currently taking

ukred profile image
ukred in reply to SlowDragon

Hi, yes, you answered me on my last post and were very helpful. In between Feb and May I really tried hard with the supplements as I had low levels in Feb. I brought them all to optimal range and will never be that stupid again. I ordered the B complex you posted about and am just waiting for the individual vitamins to run out to start them. Since the May test, I have added in Selenium, kelp and L Tyrosine. My GP won't treat me for underactive thyroid so I am doing my best to naturally kickstart it.

I had a conversation with bookish about something similar here:


ukred profile image
ukred in reply to plant_lady

Everyone seems so focussed on high blood sugar levels and I just wondered do low ones cause symptoms or are they a pointer to something else. I'm blundering around in the dark really...

plant_lady profile image
plant_lady in reply to ukred

We all are! Thank goodness for this forum to bounce ideas around. ♥️

The idea of low blood sugar piqued my interest too as mine is 5.3% but 5% is considered 'low'. I've not had chance to look into it anymore yet. I want to cut out processed sugar entirely but my health isn't there yet and I'm not sure it's a good idea if overall my blood sugar is low. Or if blood sugar level entirely unaffected by sugar consumption in which case it's moot. 😂

BrynGlas profile image
BrynGlas in reply to plant_lady

You have to remember that you ideally want your blood sugar to remain as steady as possible through the day. You don't want dramatically high or low levels, because they cause the high insulin spikes and the corresponding hypoglycemia lows. These are what makes our bodies, become resistant to insulin.

. BOTH tests showed raised cholestrol (I eat very little fat and am vegan).

Cholesterol levels have very little to do with diet, and nothing to do with fat! Fat and cholesterol are two different substances and one does not turn into the other when eaten.

Cholesterol is made in the liver, and the more you consume in your diet, the less the liver makes. The less you consume, the more the liver makes. So that there is always a constant level in the system. However, when you are hypo, and your T3 is low, the body cannot process cholesterol correctly, and it tends to build up in the blood. What was your FT3 in that private test?

Low-fat diets are a really bad idea, actually. The body needs fat. Not getting enough can cause all sorts of symptoms, such as depression.

ukred profile image
ukred in reply to greygoose

Yes. I'm grabbing at straws really. I eat a really healthy diet with loads of fruit and vegetables, nuts, beans and pulses. I guess I always associate high cholestrol with steak and cake :-D

greygoose profile image
greygoose in reply to ukred

A false idea fostered by doctors and Big Pharma reps!

But, I don't think you're grabbing at straws. That high cholesterol is more than likely saying your FT3 is too low. And low T3 causes symptoms. High cholesterol doesn't cause any symptoms. :)

I don't think that's accurate. Can you point me in the direction of the research that suggests so please?

Are you sure is states “40 and above is 'normal'”?

20 is low & 40 is quite high. So your levels of 33 & 34 are very ok.

* HbA1c below 41 mmol/mol (6.0%): Non-diabetic

* HbA1c between 42 and 47 mmol/mol (6.0–6.4%): Impaired glucose regulation (IGR) or Prediabetes

* HbA1c of 48 mmol/mol (6.5%) or over: Type 2 diabetes

Thyroid does effect metabolism which will effect blood glucose levels usually making the higher when hypo.

This article explains more about it

I was mildly hyperthyroid for nearly 5 years (wasn’t told) my HbA1c was always ok. Within a year of being on carbimazole my thyroid levels were low and the HbA1c rose to 51.

It’s usual to repeat the over range results within 3 months to confirm diagnosis but the result was duplicated on the system & they seem very keen to diagnose me type 2. Although they suggested it was “barely diabetes” and if I reduce carbs it should be ok not to start medication, retest in 3 months. I would have accepted more help and advice but “reduce carbs” and a referral to slimming world was all that was given. I had asked for weight watchers but slimming world was all he could find. This was just before lock down so I wasn’t able to attend meetings. I did my own research and used an app to track carbs. Lost quite a bit of weight.

Wasn’t able to retest until 6 months later, firstly because of covid and then the nurses could draw blood! when I was tested (6 months later) it was 35 and recently (another 6 months later) I was rested and it was 30. So on track for now.

I needed a blood glucose meter to spur me on to reduce carbs. The NHS course offered when my HbA1c hit 42 mmol/mol has been of little use to me, and the instructor warned me off using the meter, which I've ignored. Earlier, a consultant had advised me to lose weight, but said there's no such thing as prediabetes.

It's interesting how different gp's treat blood test results; when my HbA1c was measured at 42 it was virtually ignored. It was only mentioned when I had a phone appointment and I brought it up; I was told to make lifestyle changes.

I would have jumped at the chance of a course but it wasn’t offered & wouldn’t have been possible to attend at the time. The specialist suggested I join direct trial, and passed me a scrap of paper with it written down on. I brought it up with GP & he said never heard of it. I later googled it, it was a scheme that had closed the year before and wasn’t even in my area?.

I’d have also tried a monitor. After my third failed blood draw, the Doctor called and said we don’t know what to do, tell me how I can help? I suggested a monitor as then I wouldn’t need a draw and as I take carbimazole, which could be affecting levels, would it be grounds for a monitor and they immediately refused. I looked at getting my own and I didn’t like the thought of paying for refills. Plus wound healing was dreadful & I couldn’t afford continuous monitoring types.

I wonder if the consultant is saying there’s a cut off point where someone is non diabetic then 1 more point they are diabetic. Perhaps it should be referred to a sub clinical diabetes, in the same way hypothyroid can be sub clinical. In other words technically diabetes but not severely enough to bother treating.

I bought a blood sugar meter and testing kit in a large Tesco branch in 2019. Reasonable to buy too. Buy extra 'sticks' for it though if you buy one. I started by testing myself over and over again from earliest in the morning, before eating or drinking a typing which shows 'fasting blood sugar' . Mine was 5.3 - 5.5 first thing, so that was ok.

I had been low thyroid since the 90's but I had started to gain weight again and was at a loss to explain why. Though I do have a high incidence of type 1 diabetes in my family, and my mother is type 2, but not at all overweight.

Anyway, there was nothing wrong with my blood sugar levels. It was all to do with thyroid and proving it was very hard. My GP would not talk to me about my thyroid problems I was hoping that he would help me out because I had come to the conclusion that I needed T3 and not just the Levothyroxine that I had been taking. He refused because he said it was illegal in the UK! That is how much he knows about low thyroid problems. So I had to go it alone.

Remember though, that fruits are very high in sugars and can raise your blood sugar sky high rapidly, or they do with me. Everything that goes into our mouths is turned to glucose in our blood.

I had to buy a Carb and Calorie Counter book and used that to work out what to eat, limiting my carbohydrate intake to what most people would describe as too low. I found green veggies were my best friend. I rarely eat fruit because of the fructose and I eat them ( berries mostly) in season only.

I was perfectly normal, was size 12 - 14 my whole adult life, until the menopause kicked in and Lowthyroid came with it.

So it was a real shock to me when everything went wrong.

I am saying this because I found that I had to think outside the box, everything changed. And you won't find better help anywhere than on this site Group/Site.

I am now taking T3 but I had to source and buy it myself, my GP will not talk to me about it, he says it is an illegal drug !!! That is as much as many GP's know of low thyroid problems.

Good luck

I got my first meter from Lidl, but the test strips are no longer available to UK customers. In fact, they had expired by the time I plucked up courage to use it, at the suggestion of a 111 doctor when I had COVID-19. The results were trustworthy, nevertheless, and I now use a GlucoNavii.

My blood glucose levels are currently a mix of normal, prediabetic and Type 2. Under-ripe bananas aren't a problem (resistant starch), yet three clementines will produce a long-lasting spike. I can handle 250 g of porridge (especially if followed by a walk), yet 500 g is too much (but not what the Carb Monster inside me thinks is too much).

Much safer for me to stick to protein, fat and greens and not diet, as such.

Yes and yet we were all told to eat fruit by the bucketful! But the recommended NHS has been based on high carbs, cheap and plentiful for so many years. At least they are beginning to get their act together.

I am glad that you are doing the same. What I can eat now at age 69 this month and what a normal diet to me years ago consisted of is absolutely worlds apart. And it seems to be still changing. Every so often I find myself gaining weight and have to go back to the noticeboard to work out why!! It isn't a lot of fun, but it has to be done.

Btw - what app do you recommend to track carbs ? Thanks. PM if that isn’t allowed on forum - and also it’s not in response to this thread.

The particular app I used was MyFitnessPal. It will calculate calories as well as main nutrients. You can customise your goals, scan bar codes of products for accuracy. It took a little while to figure out how to use properly but found it really help me learn carb content and how to reduce them.

I ignored the upgrade feature as the basic is sufficient for me.

I also tried the Fitbit app when I got a device. & you can use without syncing to device, but I was used to using the MyFitnessPal and it had saved all my favourites, so I stuck with it. There are probably many others to try too.

No I have researched this thoroughly. Vegans are not especially at risk of Hypothyroidism.

Hedgeree profile image
Hedgeree in reply to ukred

Not sure if you're aware of the thyroid pharmacist's Izabella Wentz site? There's an interesting section on vegan diets and hashimotos. Also has references at the end, possibly interesting to have a look at?

and my GP wouldn't give me progesterone at my age

Denisemoye profile image
Denisemoye in reply to ukred

Progesterone can be increased naturally. Plus check you have no gut issues, quite often that can lead to low progesterone, estrogen dominance, insulin resistance and thyroid antibodies.

Are you sure it’s low and not high? Perhaps buy a monitor from amazon, quite cheap. They have similar symptoms (shaky, feeling like you need to eat). I assumed mine was low but found out I’m in the pre-diabetic range. I’m slim, fit and don’t really eat sugar but being a bad vegetarian, I have more carbs than protein. I’ve also had some gut issues in the past year or two and this can affect your progesterone production, causing estrogen dominance and insulin resistance. This then leads to, surprise surprise, hashimotos. The presence of thyroid antibodies means your thyroid is under attack, get these down and your thyroid will start working normally again.

I think it's dangerous to suggest low antibodies means a thyroid will start working again; even if it were possible to control the antibodies most of us have a thyroid too damaged to function by itself. That's why we're on this forum trying to get medicated properly. Getting rid of antibodies wouldn't repair the damage already done.

Antibodies don't attack the thyroid, they simply indicate that there has been an attack recently.

How do you suggest lowering antibodies?

Just read in my book ‘Why Do I Still Have Thyroid Symptoms’, that hyperglycaemia ‘and’ hypoglycaemia can cause the same issues. I’d suggest buying a monitor to see what is happening. If you have high blood sugar, your body will pump out a load of insulin and then you could swing to low blood sugar.

Low blood sugar - hypoglycaemia - can absolutely be a symptom of hypothyroidism.

This is something I’ve definitely struggled with. I find that eating a diet that’s low in fast carbs helps. Patrick Holford is pretty good on this subject.

Gut health is another issue to consider as it affects the hormones - particularly insulin- that play a part in regulating blood sugar.

Having said all of that, while there’s lots you can do to help yourself, it really ought to be with getting your thyroid levels right.

An Hba1c test gives an average blood glucose reading over a period of several months, it is not an indicator of a moment in time like those done before procedures or by diabetics. It is done to check for diabetes/pre-diabetes, and to monitor existing diabetic conditions. Your levels are actually good; I am not sure why you think they should be higher! If you think that low blood sugar levels are causing symptoms, this should be investigated by your GP, as diabetes is certainly not indicated as an issue for you.

Yes I was on anti depressants for many years and went up to the low 15 stone range! It took me a year to get out of it's grip. But it was worth it in the end.

Hi, 33 and 34 are not actually low, but the important part of what you say is that you slump in the middle of the day and need to eat. Part of your symptoms could definitely be due to some dysregulation in blood sugar control. Datis Kharrazian's 'Why do I still have thyroid symptoms when my lab test are normal' is well worth a read, for suggestions of other things that might be playing a part - a whole chapter on blood sugar included.

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