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LMU 11 – Slowing Brain Shrinkage with Vitamin B12: A Key to Preventing Alzheimer’s and Cognitive Decline


LMU 11 – Slowing Brain Shrinkage with Vitamin B12: A Key to Preventing Alzheimer's and Cognitive Decline

Source: Journal of the American Medical Association (June, 2016)

Lifestyle Medicine Update (June 4, 2016)


As we age, one of the concerning aspects is the shrinking of the brain, which is associated with an increased risk of Alzheimer’s disease and cognitive impairment. However, recent research on the neuroprotective effects of vitamin B12 has shed light on a potential solution to this problem. This article explores the findings of significant studies that highlight the role of vitamin B12 in slowing brain shrinkage and reducing the risk of dementia and Alzheimer’s disease.

Evidence from the JAMA-Psychiatry Study

A pivotal study published in June 2016 in the Journal of the American Medical Association – Psychiatry presented compelling evidence of the impact of vitamin B12 on brain shrinkage. The research followed 501 subjects aged 60 years and older, without dementia at the study’s onset, from 2001 to 2009. During the six-year follow-up, 299 subjects underwent routine MRI imaging of their brains. The results were striking, indicating that individuals with higher blood levels of vitamin B12 exhibited a significant decrease in the rate of brain tissue volume loss compared to those with lower levels of the vitamin.

The Neuroprotective Mechanisms of Vitamin B12

The protective effects of vitamin B12 on the brain are multifaceted. Firstly, it directly prevents the loss of brain cells, thereby slowing brain shrinkage. Additionally, vitamin B12 reduces the levels of homocysteine in the blood. Elevated homocysteine has been linked to brain shrinkage and an increased risk of Alzheimer’s disease in numerous studies. Thus, the ability of vitamin B12 to lower homocysteine levels presents a complementary pathway through which it may mitigate brain atrophy.

Insights from White Matter Hyperintensity

The 2016 JAMA-Psychiatry study also explored the association between vitamin B12 levels, homocysteine levels, and White Matter Hyperintensity (WMI) on MRI scans. The results revealed that individuals with lower vitamin B12 levels and higher homocysteine levels demonstrated increased WMI, strongly linked to heightened risks of cognitive decline and other mental health disorders. Considering that mild cognitive impairment (MCI) often precedes Alzheimer’s disease, these findings highlight the potential significance of vitamin B12 in early intervention strategies.

The Oxford Project to Investigate Memory and Aging (OPTIMA) and VITACOG Study

The OPTIMA and VITACOG studies focused on individuals over 70 with pre-existing MCI. Half of the participants were given a B-vitamin supplementation regimen consisting of folic acid (800 mcg), vitamin B12 (500 mcg), and vitamin B6 (20 mg) daily for two years, while the other half received a placebo. Remarkably, the group receiving B-vitamin supplementation experienced a 30% average reduction in brain shrinkage, and in some cases, the drop reached up to 53%. Moreover, cognitive tests demonstrated that the rate of brain shrinkage correlated with the pace of cognitive decline.

The Significance of Slowing Brain Atrophy

Slowing brain shrinkage or atrophy is crucial to preserving cognitive function as we age. The average brain shrinkage rate for individuals over 60 without MCI is 0.5% annually. In contrast, those with MCI have a brain shrinkage rate of 1%, while Alzheimer’s patients exhibit an average brain shrinkage rate of 2.5% annually. Consequently, any intervention that can mitigate brain atrophy holds great potential for enhancing healthy life expectancy and overall quality of life.


The evidence presented in various research studies suggests that vitamin B12 is pivotal in slowing brain shrinkage, reducing the risk of Alzheimer’s disease, and preserving cognitive function. While drug-based interventions for this purpose are yet to yield significant results, B-vitamin supplementation has shown promising effects in clinical studies. It is, therefore, prudent for individuals to monitor their blood levels of homocysteine, vitamin B12, and red blood cell folic acid levels and consider a simple B-vitamin supplementation regimen to support brain health and combat age-related cognitive decline.


  1. Medscape, May 11, 2016 (
  2. JAMA-Psychiatry, June 2016 (
  3. VITACOG study, September 2010 (

Dr. James Meschino


Dr. James Meschino, DC, MS, ROHP, is an educator, author, and researcher having lectured to thousands of healthcare professionals across North America. He holds a Master’s Degree in Science with specialties in human nutrition and biology and is recognized as an expert in the field of nutrition, anti-aging, fitness, and wellness as well as the author of numerous books.

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