“Our findings lend support for the contention that poor vitamin B12 status is a potential risk factor for brain atrophy and may contribute to cognitive impairment.”
Older adults with low blood levels of vitamin B12 markers may be more likely to have lower brain volumes and have problems with their thinking skills, according to researchers at Rush University Medical Center, Chicago.
(Aside from dietary supplements, vitamin B12 is derived from animal foods mostly – fish, meat, poultry, dairy products and eggs. Its absorption from food depends on a healthy gut, and may be limited by drugs such as acid blockers, age, and other factors.*)
This study, published Sep 27 by the journal Neurology, tracked 121 older Chicago residents as part of the Chicago Health and Aging Project (CHAP) - a large, ongoing prospective study involving a biracial cohort of 10,000 subjects over the age of 65.
• The 121 participants had blood drawn to measure levels of vitamin B12 and B12-related markers that can indicate a B12 deficiency. The same subjects took tests measuring their memory and other cognitive skills.
• An average of four-and-a-half years later, MRI scans of the participants’ brains were taken to measure total brain volume and look for other signs of brain damage.
Having high levels of four of five markers for vitamin B12 deficiency was associated with having lower scores on the cognitive tests - and smaller total brain volume.
“Our findings definitely deserve further examination,” says clinical nutritionist and lead author Christine C. Tangney, PhD. She adds:
• “Findings from a British trial with B vitamin supplementation are also supportive of these outcomes.”
• And “It’s too early to say whether increasing vitamin B12 levels in older people through diet or supplements could prevent these problems, but it is an interesting question to explore.”
On the cognitive tests, the scores ranged from -2.18 standardized units or points to 1.42 points, with an average of 0.23. For each increase of one micromole (one millionth of a mole, or 1mM) per liter of homocysteine, which is one of the markers of B12 deficiency, the cognitive scores decreased by 0.03 points.
Dr. Tangney noted that the level of vitamin B12 itself in the blood was not associated with cognitive problems or loss in brain volume.
She said that low vitamin B12 can be difficult to detect in older people when looking only at blood levels of the vitamin. (Blood tests don’t measure the amount of B12 that is being absorbed into and utilized by the cells. And because, unlike other water-soluble vitamins, B12 is stored in the liver, kidneys and other tissues, deficiencies of B12 in the blood per se often appear slowly.*)
“Our findings lend support for the contention that poor vitamin B12 status is a potential risk factor for brain atrophy and may contribute to cognitive impairment,” Dr. Tangney concludes.
The study was supported by the National Institute on Aging.
Source: Rush University Medical Center news release, Sep 27, 2011
* See “Could a Common B-12 Deficiency Be Causing Your Symptoms?” by Dr. Dana Myatt, NMD, and Mark Ziemann, RN.