Could high oral B12 intake (1000-2000mcg/day) cause hyperthyroidism? I noticed from recent blood work that my serum B12 was lower than it used to be: currently at 344 pmol/L for a range between 150 to 600 pmol/L. It used to be 732 pmol/L in 2018. I was diagnosed with Chronic Fatigue Syndrome last March, and suffer from symptoms that might suggest I need a boost of B12: extreme exhaustion, depression, anxiety, constantly catching colds or even flus, and feeling of weakness in my legs. So, 4 days ago I began supplementing with B12 and I immediately felt like I had “just woken up after a very long nap”, like a magical switch after many years of progressive debilitating condition. Now, I understand that my initial reaction to B12 was possibly sychosomatic, as it takes a while for it to work. However, since starting the B12 5 days ago, I have started to suffer from symptoms of hyperthyroidism. Could B12 intake cause hyperthyroidism? Really feeling poorly and can’t even sleep.
B12 intake cause of my sudden symptom... - Pernicious Anaemi...
Pernicious Anaemia Society
I’m not a medical professional but I’ve never heard that high B12 intake could cause such symptoms.
However, I would mention that autoimmune illnesses often come in clusters. For example, I have Graves’ disease (hyperthyroidism), PA and vitiligo. So antibody testing is what I’d be asking my GP to consider.
Thank you so much for your reply JanD236. I forgot to mention that I was diagnosed with Hashimoto’s in 2009, with elevated TSH and antibodies above range for the anti-thyroglobulin, but not for TPO’s. I was treated for a year and a half with synthroid. However, my hypothyroidism became hyperthyroidism and I had to stop the treatment and take anti-thyroid medication for a few months. I haven’t been treated ever since. I check my thyroid every year through blood test, but since my tsh is always great, I never have the possibility of testing T3 or T4. Every year, I have 1 or 2 episodes of hyperthyroidism lasting at most 3 days but this time it has been more intense than I remember it to be. I agree with you, I should ask the doctor for antibodies testing.
And a full thyroid panel too given your history.
That’s a good idea too, for sure.
If you were diagnosed with Hashimotos then it is possible to swing between being hypo and hyper. Taking the anti-thyroid drugs did sound drastic. Do you have your results from that time ? Was the T3 tested ?
Hi Marz. Thank you for your message. I know it seems unlikely to need anti-thyroid medication for Hashimotos. I moved from France to Canada in 2010. Upon my arrival, I developed weird symptoms that I attributed to anxiety and this for over 6 months. Eventually I met with a doctor in a walk-in clinic who took the time to look at my blood test results ( the ones then taken in Canada). He realized that I had been dealing with hyperthyroidism for those 6 months. I had lost a lot of weight then and my heart kept beating faster than I am used to. To answer your questions: I do have my blood test results that showed I have Hashimoto from 2009.
My TSH was then 5.76 mUI/L and the range was from 0.30 to 4.00 mUI/L.
My free T4 was at 11.4 pg/ml for a range between 8.9 to 17.6 pg/ml.
My free T3 was 3.7 pg/ml for a range between 2.0 to 4.4 pg/ml.
My anti-thyroglobulin antibodies were above range at 162.00 UI/ ml ( normal range is less than 115 UI/ml.
My anti- thyroperoxydase antibodies were at 10.16 UI/ml and normal range is less than 34.00 UI/ml.
Finally, my anti TPO was inferior at 1.00 UI and normal range was less than 1.5 UI/L.
When I moved to Canada, I wasn’t able to have directly access to my blood tests until 2014 unfortunately. Otherwise, I would have probably detected the hyperthyroidism sooner.
I apologize, I got mixed up on my last result. I meant Thyroid Stimulating Hormone Receptor Antibody instead of anti TPO.
It is also possible to have both Graves and Hashimitos I have read. The results above do indicate you were Hypo as you mentioned. How did the results change when you were Hyper ? Lots of knowledgeable people on the Thyroid UK Forum who will be able to share their experience better than me - I have Hashimotos as well as B12 issues caused by surgery and I self inject ...
It is often mentioned that with Thyroid issues it is good to have optimal levels of B12 - Folate - Ferritin - VitD. B12 around 500 - Folate and Ferritin mid range and VitD at 60 ( if measured in ng/L )
I wish I had had access to my blood test results in 2011-2013... I went to walk-in clinics and always saw different doctors. In 2014, I learned I could have access to my blood test directly online by signing up a request form. So I now have access to all my results since 2014 but not from before.
I know that in 2014 my tsh was once at 0.11 mU/L for a range between 0.30 to 5.50 mU/L, but the doctor wasn’t worried. Then the tsh went back to a “normal” level and has been at around 1.61 mU/L since then.
I did check my vitamin D level, which is good at 83.
My ferritin is too low: at 40 ug/L and the doctor I saw last time told me I should aim for 70 ug/L .
I never tested for the folate. I am going to the clinic tomorrow and will request some blood work.
Thank you so much for your help and the links. I did post on the Thyroid UK forum earlier today 😊.
Hope you will soon feel better .. will take a peep at your new post 😎
Thank you so much ☺️. I hope so too. I will post my blood results once I get them. I was a bit lazy ( after 3 nights of sporadic sleep), and only copy pasted the same initial message on the thyroid forum but will give more info as requested.
Am hoping greygoose - SeasideSusie and SlowDragon will soon be awake and respond !! It's only 7.30 am here ! Also there are lots of other very informed and helpful people. Check out Greek chick- she is in Canada too ...
Thank you for all your support, so deeply appreciated right now. I will definitely check everybody out! 😊
It’s 11:36 pm here in Vancouver so I will try to get some sleep 😴 .
Just an update as I am back from the doctor: it’s unlikely the B12 caused my symptoms. The doctor thinks I have a flu-like illness as well as an adverse reaction to an anti anxiety medication I started taking 3 weeks ago ( Buspar.)
I did some blood work and having the B12 re-tested and thyroid. I also had an ECG. I will let you know once I get the results.