There is an increased risk of low vitamin B12 levels with Hypothyroidism and/or Hashimoto’s thyroiditis.
This is something I was never told by my medical team, nor were vitamin B12 levels ever assessed despite all the typical symptoms of low levels, not until I insisted.
Yet on average 27% (some studies report up to 50%) of those with Hashimoto’s and/or Hypothyroidism also have low vitamin B12 levels, often due to Pernicious Anaemia. (1)
I suspect this may be a very conservative estimate as I feel the lower level for detection of vitamin B12 deficiency are set way to low.
Many of my clients (and myself) experienced symptoms associated with vitamin B12 deficiency way above that lower cut off point.
What is pernicious anaemia?
Pernicious anaemia is an autoimmune condition, much like Hashimoto’s, but in this case the immune system creates antibodies against the parietal cells in the stomach and against intrinsic factor. The parietal cells produce stomach acid to help you break your food down, so nutrients such as vitamin B12 can be extracted. They also produce intrinsic factor which binds to vitamin B12 and safely transports it to the far end of the small intestine where it can absorbed.
When antibodies are created against either parietal cells or intrinsic factor it impairs B12 absorption and eventually leads to deficiency.
What symptoms are associated with low vitamin B12 levels?
There are a multitude of symptoms and can be broken into the following categories (2)
Neurological
- Paresthesia: abnormal sensation, typically tingling or pricking (‘pins and needles’)
- Numbness in hands and feet, reduced skin sensation
- Impaired fine finger movement
- Ataxic gait (unsteady, staggering gait)
- Balance problems/loss of sense of position
- Reduced or absent reflexes
- Clumsiness/lack of coordination
- Aphasia (problems with speaking, writing, reading)
- Sensory loss (loss of taste, smell or hearing)
- Positive Romberg sign (unable to maintain balance with eyes closed)
- Burning legs and/or feet
- Lhermitte’s sign (electric sensation that travels down your neck and back)
- Blurred vision
Neuro Psychiatric and Psychological
- Memory and concentration problems
- Dementia, confusion
- Brain fog/decreased mental concentration
- Irritability, emotional lability
- Personality changes, mania, paranoia
- Depression
- Psychosis, delirium, paranoia
Aneamia
- (Extreme) Fatigue
- Shortness of breath
- Dizziness/feeling faint/vertigo
- Postural hypotension (drop in blood pressure upon standing)
- Pallor
Gynaecological and Urological
- Infertility
- Loss of libido/impotence
- Menstrual problems/pains
- Incontinence
- Cystitis, bladder inflammation, bladder infections
- Pyelonephritis (kidney infection)
Gastrointestinal
- Loss of appetite
- Glossitis (pain, redness, swelling in mouth and tongue)
- Diarrhoea
- Weight loss
- Nausea, vomiting
- Stomach problems, heartburn, discomfort
Other
- Fever
- Sleep disturbance
- Tinnitus
- Hair loss/premature grey hair
- Brittle nails
Which symptoms tend to present first?
Neurological symptoms tend to be the first to occur. A recent study has highlighted this in the elderly. It showed that participants with a vitamin B12 level lower than 408 pmol/L exhibited the following:
- Increased white matter hyperintensities (which are associated with functional decline, gait disturbances, depression, disruption of neural networks and cognitive problems)
- Delayed nerve signalling
- Slower cognitive processing
I experienced all of the neurological symptoms, yet was told I could not possibly be deficient despite being smack bang on the lower cut off point, displaying all the symptoms and already being diagnosed with Hashimoto’s and Hypothyroidism. Yet as my blood work did not show anaemia (it had at various points in the past) I could not possibly be vitamin B12 deficient.
Aneamia is recognised as an end stage symptom of a vitamin B12 deficiency with neurological, metabolic and cellular related symptoms displaying much earlier. Yet guidelines are still set according to when aneamia presents as a symptom, by this point neurological symptoms could be permanent, as it can take 3-5 years to deplete levels far enough to display outright anaemia!
What is the current reference range?
Current NICE guidelines (UK) show the following levels (3)
- Less than 133 pmol/L : Confirmed deficiency
- 133–258 pmol/L : Indeterminate; possible deficiency
- More than 258 pmol/L : Deficiency unlikely
Neurological symptoms are likely occurring in those with levels higher than 258 pmol/L which is the threshold to show a deficiency being unlikely.
Total B12 tests vs Active B12 tests
One of the reasons that symptoms may be occurring above this level is that the standard test tends to be Total B12, this test measures both holo-transcobalamin (active B12) and holo-haptocorrin (inactive B12) and we can’t use the inactive portion. Another is that the level is set to detect anaemia, not neurological symptoms.
So it’s important if you suspect a vitamin B12 deficiency then you ask for holo-transcobalamin to be tested too not just Total B12 as the issues listed above were associated with low holo-transcobalamin when tested.
What other tests might be useful?
If your levels fall below mid range or below the 408 pmol/L and you display symptoms or have Hashimoto’s and/or Hypothyroidism then ask for methylmalonic acid (MMA) and homocysteine to be measured too as they are early indicators of a B12 deficiency.
Further research is needed
The research paper I quoted in the elderly calls for reference levels to be re-assessed. Further research also needs to be done in other age groups, as this is not just an issue that affects the elderly alone, I was 38 when I was diagnosed and had been struggling with symptoms for years!
My advice would be to get levels tested with Hashimoto’s and Hypothyroidism regardless, but especially if you’re experiencing any of the symptoms listed. From my experience a lot of the symptoms of Hashimoto’s and Hypothyroidism overlapped, so if in doubt ask to be tested.
Need further help?
If you’re struggling to work out what testing you need for vitamin B12 or any other potential nutrient deficiencies I offer 30 minute and 60 minute Test Interpretation Sessions, which include advice on which tests may be appropriate for you personally.
Please get in touch via email to discuss further at helen@helenmallaburn.com
If you already have test results and want to book to discuss them you can do so below:
You might also like to read my previous article on the impact of leaky gut on Hashimoto’s, as this can impact overall gut health and ultimately vitamin B12 and other nutrient absorption.