IS YOUR B12 LEVEL ACTUALLY NORMAL?
Dr. Krista Coombs
April 9, 2025
This week in INSIGHTS for Healing by Design, I’d like to introduce you to an interesting study, published in Annals of Neurology, analyzed 231 healthy older adults to determine at what Vitamin B12 level neurological symptoms of deficiency show up. The median B12 blood concentration for these participants was at first glance, a decent 414.8 pmol/L which seems in alignment with Alberta’s assessment that anything above 160 pmol/L is within “normal” range. But, and this is important, the participants even with B12 values in the 400’s, experienced significant neurological symptoms, with the most notable being:
➡️ Slower mental processing
➡️ Delayed visual evoked potentials - an indicator of impaired myelin function at nerves (myelin is the sheath around nerves)
➡️Greater white matter hyperintensity volume on MRI - associated with brain decline and neurodegenerative disease
➡️ Increased serum Tau protein - a biomarker of neurodegeneration linked to Alzheimer’s and other types of dementia
The study challenges the current clinical cutoff for B12 deficiency and suggests that functional B12 markers; such as holo-transcobalamin (holo-TC), methylmalonic acid (MMA), and homocysteine, should be used alongside serum B12 levels in blood tests for a more accurate assessment of neurological risk. These functional markers are more how your cells are handling B12 rather than just what is in your blood.
In my practice, I have tested B12 along with the marker homocysteine for many years, and for patients open to paying for some functional testing, I can look at MMA too, but not yet the holo-TC.
THE IMPORTANT TAKEAWAYS
I really hope you now understand that B12 plays a critical role in myelin maintenance (the sheaths around nerves), nerve function, and brain health, but unfortunately, the standard definition of deficiency in Alberta of 160 pmol/L is ignoring the fact that neurological damage can occur in people even when B12 levels are in the normal range!
I run a lot of comprehensive bloodwork and a common finding is subclinical B12 deficiency, something patients often aren’t aware of because they are told it’s normal when in fact it is part of the reason for continuation of neurological symptoms, especially in the aging population. I want your B12 level to at least be above 500 pmol/L and homocysteine under 8 umol/L.
You can have suboptimal B12 levels even if you eat a diet rich in animal products (and especially if you do not) often because of unresolved gut issues, low stomach acid, and age-related malabsorption that can all impair B12 uptake into your bloodstream. Imagine
what this means - millions of people, especially older adults, are at risk for progressive neurological decline and yet it’s pretty EASY to remedy with lifestyle adjustment and supplementation!
WHAT YOU CAN DO TODAY
Work with me to test your blood for both serum B12 and homocysteine. Sadly, B12 in Alberta currently can only be tested once a year if the testing showed a level above 160 pmol/L. If you already have had your level tested and it is below 500 pmol/L, we can still test homocysteine and determine how to move forward for you. My Comprehensive Bloodwork Package includes these markers as well as many more than are not typically tested by most physicians in Alberta.
If you aren’t yet able to do the blood testing but you have suspicious symptoms of low B12, at least put effort into improving your diet and also supplementing with any of the B Vitamins because they are water soluble and non-toxic even at high doses. But, not all forms of B12 are created equal. Many supplements contain cyanocobalamin, a poorly absorbed, synthetic form of B12. Instead, you should prioritize the active, bioavailable forms of B12, such as methylcobalamin and adenosylcobalamin.
✅ Pro B Complex by AOR is one of my favorite Canadian B complex products on the market today. It contains a full-spectrum B vitamin, including methylcobalamin (active B12) and other essential B vitamins to support brain function, cardiovascular health, hormone production, detoxification and metabolism. All the B vitamins work together, so generally I suggest taking them altogether. Dosing is 1-3 capsules/day, depending on your needs, and always taken with food.
Please don’t wait for symptoms to show up because by then, neurological damage may already be underway and that can be very challenging to reverse. Support your brain, energy, and longevity with optimal B12 (along with the other B’s as they work together) today. Shop in my supplement dispensary, Fullscript, for high quality products to support a healthy diet.
Reach out to me with any questions.
In health,
Dr. Krista Coombs xx
DrAc, IFMCP
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