Scientists Just Found a Major Problem With Vitamin B12 Guidelines – And Your Brain Might Be at Risk
Your brain might not be getting enough B12 — even if your levels are considered “normal.†A new study suggests that older adults with lower B12, even within the accepted range, show signs of cognitive decline and brain damage. Researchers found that these individuals had slower thinking and reaction times, along with white matter lesions linked to dementia.
FAB RESEARCH COMMENT:
Standard measures of blood levels of Vitamin B12, and the 'norms' derived from these, are not sufficiently sensitive to detect functional deficiencies of this key vitamin in older adults, new research shows.In healthy older adults with supposedly 'normal' blood levels of Vitamin B12, lower B12 levels were associated with
- slower mental processing speed - assessed both objectively (via recording of brain electrical responses to visual stimuli) and via reaction times
- structural abnormalities of the kind associated with age-related cognitive decline and dementia.
- Up to 80% of what standard blood tests include as B12 is an 'inactive' form, which the brain and body cannot use.
Why detecting Vitamin B12 deficiency matters
Vitamin B12 is needed to make red blood cells, DNA and myelin - a fatty substance that coats major nerve fibres, and speeds the transmission of signals in the brain and nervous system.Vitamin B12 also works with vitamin B6 and folate (vitamin B9) to recycle homocysteine - a toxic byproduct of normal metabolism. High levels of homocysteine significantly increase the risks for cognitive impairment and dementia, and indicate inadequate levels of any or all these B vitamins.
Deficiences of Vitamin B12 can therefore lead to a wide range of psychiatric and neurological as well as physical health symptoms. And if prolonged, severe B12 deficiency causes irreversible damage to the brain and nervous system, including paralysis and ultimately, death.
Importantly, psychiatric symptoms are often the first signs of Vitamin B12 deficiency - as these often occur without either obvious anaemia, or any of the more 'classic' neurological symptoms (such as numbness, tingling sensations, pain, or problems with movement, co-ordination or balance).
The fact that psychiatric and/or neurological symptoms from B12 deficiency often occur before - or without - any obvious anaemia means that B12 deficiency can easily go unrecognised by clinicians, or lead to misdiagnosis.
These new findings - in older adults with lower but supposedly 'normal' levels of B12 showed significantly more impairments of brain structure and function of the kinds associated with age-related cognitive decline and dementia - therefore add major weight to longstanding calls for clinical measures and norms for Vitamin B12 deficiency to be revised and improved.
Meanwhile, B12 supplementation is generally regarded as safe. And clinical guidelines already indicate that treating symptoms, rather than relying on single blood measures, is the most approproate way to manage absoprtion problems such as pernicious aneamia, or atophic gastritis - which can occur at any age - but are particularly common in older adults.
For details of this research, see:
And see also this news article reporting on this study
Different possible Reasons for low Vitamin B12 status
Vitamin B12 is a fietary essential - and found naturally only in animal-based foods. The best dietary sources include red meat (beef, pork, lamb), fish (salmon, tuna, trout), dairy products (milk, cheese, yogurt), and eggs. To avoid B12 deficiency, vegans (and many vegetarians) must therefore use supplements, and/or consume enough B12 from specially fortified plant-based foods.
However in the general population, low Vitamin B12 levels often reflect poor absorption of Vitamin B12 rather than low dietary intakes. This particularly applies in older adults, as absorption problems increase significantly with age.
Many common medications also impair the absorption of B12, including metformin (used to manage diabetes), 'antacids' (especially proton pump inhibitors) widely used for 'indigestion' or reflux, and some antibiotics, anong others; while nitrous oxide or 'laughing gas' (used as an anaesthic, but also widely abused as a recreational drug) inactivates vitamin B12.
For further information suitable for both health professionals and the general public, please see the excellent books:
And for more information on Vitamin B12, see
Your brain might not be getting enough B12 — even if your levels are considered “normal.”
- A new study suggests that older adults with lower B12, even within the accepted range, show signs of cognitive decline and brain damage.
- Researchers found that these individuals had slower thinking and reaction times, along with white matter lesions linked to dementia.
Normal B12 Levels Still Linked to Brain Deficiency
Getting the recommended amount of vitamin B12 is essential for making DNA, red blood cells, and nerve tissue. But new research suggests that meeting the minimum requirement may not be enough — especially for older adults.
In fact, having lower B12 levels, even within the normal range, could increase the risk of cognitive impairment.
A study led by researchers at the University of California, San Francisco found that healthy older adults with lower B12 levels showed signs of neurological and cognitive decline. These individuals had more damage to the brain’s white matter — the nerve fibers that enable different parts of the brain to communicate — and performed worse on tests measuring cognitive and visual processing speeds compared to those with higher B12 levels.
The study was published in Annals of Neurology on February 10.
Rethinking B12 Guidelines for Brain Health
Senior study author Dr. Ari J. Green, from UCSF’s Departments of Neurology and Ophthalmology and the Weill Institute for Neurosciences, says the findings raise concerns about current B12 recommendations.
“Previous studies that defined healthy amounts of B12 may have missed subtle functional manifestations of high or low levels that can affect people without causing overt symptoms,” said Green, noting that clear deficiencies of the vitamin are commonly associated with a type of anemia.
“Revisiting the definition of B12 deficiency to incorporate functional biomarkers could lead to earlier intervention and prevention of cognitive decline.”
Lower B12 Correlates with Slower Processing Speeds, Brain Lesions
In the study, researchers enrolled 231 healthy participants without dementia or mild cognitive impairment, whose average age was 71. They were recruited through the Brain Aging Network for Cognitive Health (BrANCH) study at UCSF.
Their blood B12 amounts averaged 414.8 pmol/L, well above the U.S. minimum of 148 pmol/L. Adjusted for factors like age, sex, education, and cardiovascular risks, researchers looked at the biologically active component of B12, which provides a more accurate measure of the amount of the vitamin that the body can utilize.
In cognitive testing, participants with lower active B12 were found to have slower processing speed, relating to subtle cognitive decline. Its impact was amplified by older age. They also showed significant delays responding to visual stimuli, indicating slower visual processing speeds and generally slower brain conductivity.
Cognitive Decline Could Affect More People Than Expected
MRIs revealed a higher volume of lesions in the participants’ white matter, which may be associated with cognitive decline, dementia or stroke.
While the study volunteers were older adults, who may have a specific vulnerability to lower levels of B12, co-first author Alexandra Beaudry-Richard, MSc, said that these lower levels could “impact cognition to a greater extent than what we previously thought, and may affect a much larger proportion of the population than we realize.”
Beaudry-Richard is currently completing her doctorate in research and medicine at the UCSF Department of Neurology and the Department of Microbiology and Immunology at the University of Ottawa.
Rethinking B12 Deficiency and Supplementation
“In addition to redefining B12 deficiency, clinicians should consider supplementation in older patients with neurological symptoms even if their levels are within normal limits,” she said.
“Ultimately, we need to invest in more research about the underlying biology of B12 insufficiency, since it may be a preventable cause of cognitive decline.”
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