Vitamin B12 and Dementia
Diets High in B12 May Prevent Memory Loss in the Elderly
The results of a five year study conducted at Oxford University and published in the journal, Neurology, show those with higher blood levels of vitamin B12 are six times less likely to experience brain shrinkage and dementia compared to those with lower levels.
The study followed 107 volunteers aged between 61 and 87 and found a greater decrease in brain volume among those with lower vitamin B12 and holoTC levels, an early marker of B12 deficiency. None of these were vitamin B12 deficient. The volunteers were split into three groups, according to their B12 levels. Even those with the lowest levels were still above the benchmark used by scientists to define B12 deficiency.
The study did not look at whether taking vitamin B12 supplements would have the same effect on memory.
Homocysteine Link
Other research in Sweden, the Kungsholmen Project, also found links between Alzheimer’s disease and vitamin B12 deficiency. The study focused on those aged 75 and older over a three year period and found more than half of those diagnosed with dementia had low levels of B12 or folate. The scientists involved believe vitamin B12 deficiencies affect Alzheimer’s by influencing neurotransmitters or levels of the blood protein homocysteine, an amino acid. Vitamin B12 or folate deficiency can increase homocysteine levels which in turn can lead to Alzheimer’s disease.
Studies have shown high homocysteine levels are linked to brain damage. Researchers at Japan’s Tohoku University took brain scans of 150 elderly people and checked each individual’s homocysteine levels. Higher homocysteine levels resulted in greater brain damage. Another study cited in the New England Journal of Medicine followed the health of 1,000 elderly people without dementia and measured their homocysteine levels. During the following eight years, 111 were diagnosed with dementia, of which 83 were diagnosed with Alzheimer’s. Those with high blood levels of homocysteine had double the risk of contracting Alzheimer’s.
Vegetarians Most Vulnerable
Vitamin B12 deficiency, or pernicious anaemia, can also cause neuritis, an inflammation of the nerves, and dementia. Because the body stores vitamin B12, it may take several years to become deficient. Deficiency is more of a concern for strict vegetarians than for meat and dairy eaters. B12 is not found in the vegetable world other than in certain fermented foods. Menstrual problems and amenorrhea, lack of menstrual flow, may occur in women deficient in B12.
Vitamin B12 helps maintain energy levels and protects nerve coatings. It is needed for the production of red blood cells and in the synthesis of DNA and RNA, which are important rebuilding processes in the body.
Deficiency has also been linked with mental health problems and symptoms include irritability, agitation, depression and psychosis.
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