What if I told you that you could have a serious vitamin B12 deficiency, suffer nerve damage, memory loss, depression, or balance problems, and still have a completely normal blood count?
It happens more often than many people realise.
A landmark study published in the New England Journal of Medicine followed 141 patients with neurological and psychiatric disorders caused by vitamin B12 deficiency. Shockingly, 28% had none of the classic blood changes doctors are taught to look for. Nineteen patients had completely normal complete blood counts (CBCs), and another 18 had normal or borderline vitamin B12 levels, despite already having significant neurological disease.
The reason lies in how the body uses vitamin B12.
Your liver stores several years' worth of B12, so when intake falls or absorption becomes impaired, your body quietly uses those reserves. During this stage, damage can begin long before routine blood tests become abnormal.
The first marker to fall is holotranscobalamin, the active form of B12 delivered directly to your cells. As deficiency progresses, methylmalonic acid (MMA) and homocysteine begin to rise because vital B12-dependent enzymes can no longer function properly.
The routine CBC is usually the last test to change. Red blood cells live for around 120 days, so it may take months before the characteristic enlarged red blood cells appear. By then, nerve damage may already be well underway.
Vitamin B12 is essential for producing methionine, a molecule your nervous system relies on to maintain the myelin sheath, the protective insulation surrounding every nerve fibre.
When myelin begins to break down, symptoms may include:
• Tingling or numbness in the hands and feet
• Burning sensations
• Poor balance or frequent falls
• Muscle weakness
• Brain fog
• Memory loss
• Depression or anxiety
• Personality changes
• Dementia
• Psychiatric disorders
Who is most at risk?
• Vegans and strict vegetarians
• Adults over 60
• People taking acid-reducing medications such as proton pump inhibitors
• Anyone taking metformin for diabetes
• People who have had gastric bypass surgery or bowel surgery
• Those with pernicious anaemia, an autoimmune disease that prevents proper B12 absorption
One of the biggest misconceptions is that a "normal" serum B12 level rules out deficiency.
It doesn't.
Many experts now recommend measuring methylmalonic acid (MMA) and holotranscobalamin, which detect functional B12 deficiency much earlier than a standard serum B12 test. Waiting until the CBC becomes abnormal may mean waiting until significant neurological injury has already occurred.
There is encouraging news.
In the Lindenbaum study, every patient evaluated after treatment showed improvement in their neurological or psychiatric symptoms. Early diagnosis and treatment can make a remarkable difference.
The lesson is simple: if you have unexplained neurological symptoms, don't assume a normal blood count means everything is fine. Vitamin B12 deficiency can hide in plain sight.
Written by Maryjayne Aria Author of Immune Health, Terrain and GcMaf
For More Health Insights see https://maryjaynearia.com/blog/
References:
Lindenbaum J, et al. New England Journal of Medicine. 1988.
Stabler SP. New England Journal of Medicine. 2013.
