Vitamin B12: The deficiency that may be contributing to your neuropathy, tinnitus, and poor sleep
About one year into my illness, I learned from organic acids testing that my methylmalonic acid levels were high, a standard indication of a B12 deficiency. This was somewhat surprising, as I had been both supplementing and consuming a diet rich in B12 for some time. Additionally (a fact that I later learned was misleading), my blood levels were high. Vitamin B12 has a complex utilization pathway, however, and the post-covid disruption to my intestinal health had compromised my ability to appropriately utilize it.
When utilization pathways are disrupted, the standard recommendation is intramuscular injections, which bypass many of the ways that absorption can fail. I began receiving every-other-day cyanocobalamin via this method, first from REVIV, and later administered by my husband at home. My sleep immediately improved by leaps and bounds. My neuropathy, which had been continuously progressing, receded.
B12 Deficiency & Post-Covid Conditions
The following figure highlights the overlap in B12 deficiency and post-Covid symptoms.
Figure: Vitamin B12 action on COVID-19 and post–COVID-19 symptoms. Abbreviations: GBS, Guillain–Barre syndrome; PCR, polymerase chain reaction. Source: The role of vitamin B12 in viral infections: a comprehensive review of its relationship with the muscle-gut-brain axis and implications for SARS-CoV-2 infection,” PubMed
Critically, and most pertinent to common post-covid issues, Vitamin B12 is essential for myelin synthesis, nervous system health, and endothelial function. Despite the fact that a B12 deficiency isn’t commonly explored as a potential cause by post-covid practitioners, neuropathy is a common and well-known symptom of deficiency. B12 also reduces inflammation and oxidative stress, and is important for immune function (source). Additionally, B12 deficiency is associated with tinnitus (source).
Why supplements won’t cut it
Vitamin B12 has a complex processing pathway, with many factors having the potential to interfere. Infections, low stomach acid, and intestinal problems such as Small Intestinal Bacteria Overgrowth (SIBO) and Inflammatory Bowel Disease (IBD), all of which are commonly found in post-covid patients, have the potential to disrupt key utilization pathways.
“But my blood levels are high”
A standard post-covid work-up typically includes a test for blood levels of B12. If someone has been supplementing (via a multivitamin or otherwise), these levels are often in or even be above the normal range. As per the NHS however, this test can be misleading. The current widely-used blood test measures the total amount of vitamin B12 in your blood, but does not differentiate between “active” and “inactive” forms. Even if the majority of the B12 in your blood is inactive, a blood test may show that you have normal levels, even though your body isn’t able to make use of it (source).
There are blood tests which can determine how much of the B12 in your blood is the active form, but these are not widely available.
“But I’m seeing a leading neurologist”
I saw multiple neurologists during the period in which I suffered from neuropathy, and none of them suggested that a deficiency be the issue. These neurologists weren’t practicing in the middle of nowhere, either - they were associated with some of the most well-known post-covid centers in the country. Rather than explore potential deficiencies, I was subject to electrical nerve tests and a punch biopsy. When I brought up the fact that I suspected a potential B12 deficiency with one of them, he referred to the fact that my blood levels were high as an indication that it could not be possible.
How to take action
Testing for B12 deficiency can be complex, and many providers aren’t well-versed in diagnosis. When test results are inconclusive but there are clinical features of deficiency, it is recommended that treatment be started as soon as possible to avoid further neurological impairment (source). If you are suspicious that you may have a deficiency and do not have access to a knowledgable provider, a potential route is to try a single injection and observe how you respond. This could be by requesting a prescription injection from your primary care physician or purchasing an over-the-counter injection at a clinic such as REVIV. Those with a deficiency might be tired following a shot or have other reactions, as their body suddenly has resources for critical functions, while those with sufficient B12 reserves will likely not respond at all. If you determine you do have a deficiency, supplies can be prescribed by a doctor or purchased online to continue shots at home.
Resources
The role of vitamin B12 in viral infections: a comprehensive review of its relationship with the muscle-gut-brain axis and implications for SARS-CoV-2 infection • PubMed
Be well: A potential role for vitamin B in COVID-19 • PubMed
Therapeutic role of Vitamin B12 in patients of chronic tinnitus: A pilot study • PubMed
Diagnosis: Vitamin B12 or Folate Deficiency Anaemia • Link
Guidelines for the diagnosis and treatment of cobalamin and folate disorders • Link
Vitamin B12 in Relation to Oxidative Stress: A Systematic Review • PubMed
Film: Sally Pacholok (87-minute film based on the true story of an ER nurse, Sally Pacholok, who uncovered an epidemic of misdiagnoses) • Link
