MONDAY, Sept. 26 (HealthDay News) -- Too little vitamin B-12 may
be associated with smaller brain size and more problems with
thinking skills as people age, new research suggests.
And the number of people who suffer from B-12 deficiencies may
be greater than thought because current methods for measuring
levels of the vitamin may not be accurate, said Christine C.
Tangney, lead author of the study published in the Sept. 27 issue
Neurology. The study was funded by the U.S. National Institute on Aging.
The researchers assessed the study participants' vitamin levels
not only from B-12 levels themselves, but from blood metabolites
that are considered markers of B-12 activity (or lack of it) in the
But the findings aren't nearly enough to start recommending
people take B-12 supplements to jumpstart their brains, cautioned
Dr. Marc L. Gordon, chief of neurology of Zucker Hillside Hospital
in Glen Oaks, N.Y. Gordon was not involved with the study.
"It's not clear exactly if you have a measurement like this whether it's causal or that lowering the marker will drive a change in the risk," he said.
And unless you're a strict vegan, most people do get enough
B-12, which is critical for brain health, from their diet -- mainly
from animal-derived products, added Gordon, who is also an
Alzheimer's researcher at The Feinstein Institute for Medical
Research in Manhasset, N.Y.
B-12 is critical for brain health but can become an issue as
people get older because the body becomes less able to absorb it.
Also, certain drugs can affect absorption. These include proton
pump inhibitors, widely used to reduce stomach acid, and the hugely
popular diabetes drug metformin (Glucophage).
The authors of the new study looked not only at B-12 levels but
at five different blood markers for the vitamin that indicate
"where B-12 is active in the tissues," said Tangney, who is
associate professor in the department of clinical nutrition at Rush
University Medical Center in Chicago.
These markers may actually be better indicators of how much B-12
is absorbed in the body than B-12 itself, she added.
In this study of 121 black and white seniors participating in
the Chicago Health and Aging Project, volunteers had their blood
drawn and tested for B-12 and related metabolites; they also took
17 tests to measure their memory and mental acuity (cognitive
About 4.5 years later, the researchers measured the
participants' brain volumes using MRI scans, and checked for other
signs of brain damage. High levels of four of the five markers were
linked with smaller brain volume and/or lower scores on cognitive
tests, compared with people who had lower levels of the
"This suggests that measuring B-12 levels in itself is not enough to tell if a person is deficient or not," Tangney said. "We need to be careful and think about other indicators."
If a person's B-12 levels are borderline normal, it might be
reasonable to check other measures, said Gordon.
Tangney said the study results suggest that B-12 deficiencies
contribute to brain atrophy (shrinkage), which in turn can
contribute to cognitive problems. However, she also warned against
making dietary changes or drawing too-firm conclusions from these
findings, noting that they were based on data from only a small
number of people.
The U.S. National Institutes of Health's Office of Dietary
Supplements has more on