Help pack a million meals for struggling seniors on 9-11. Volunteer today

AARP Bulletin

Health Discovery

Vitamin B12 Levels LInked to Memory Skills and Brain Size

Vitamin B12 Levels Linked to Memory Skills and Brain Size

En español | A new study links vitamin B12 deficiency to brain shrinkage and memory problems in older adults.

The study involved 121 adults age 65 and older who are part of the ongoing Chicago Health and Aging Project.

Subscribe to the AARP Health Newsletter

Researchers tested participants for thinking skills and blood levels of vitamin B12, as well as for the presence of blood markers that accumulate when the body does not have enough B12. Four to five years later they had MRI brain scans.

Level of B12 Affects Brain Size, Thinking Skills- a B- Vitamin

Seniors with low vitamin B12 may be more likely to have smaller brain size. — Visuals Unlimited/Getty Images

Scientists at Rush University Medical Center in Chicago found those who had the markers linked to vitamin B12 deficiency were more likely to have the smallest brains and the lowest scores on tests measuring short-term memory, concentration and other thinking processes.

As the brain ages, it begins to shrink and lose some volume. More severe brain shrinkage occurs in those with dementia, including Alzheimer's disease.

While B12 occurs naturally in beef, fish, shellfish, dairy products and many other foods, the problem often is not with diet but absorption, says Christine Tangney, associate professor of clinical nutrition at Rush and one of the study authors. Some prescription medications used to treat heartburn, stomach ulcers and type 2 diabetes can limit the absorption of B12, as can the thinning of the stomach lining, which can happen with age.

The study, published in the journal Neurology, shows that diagnosing B12 deficiency can be difficult. Indeed, all of the study participants had B12 blood levels measuring in the normal range.

Still, 15 to 17 percent had elevated levels of biomarkers indicating B12 deficiency.

"Even though the B12 in the blood may be at a certain level," Tangney says, "there may not be enough in the tissues."

"It's an important study, because it seems to suggest that just checking for serum B12 levels in elderly patients is probably not enough," says Daniel C. Potts, M.D. associate clinical professor of neurology at the University of Alabama School of Medicine in Tuscaloosa.

Next: Liver and salmon and clams, oh, my! »

Topic Alerts

You can get weekly email alerts on the topics below. Just click “Follow.”

Manage Alerts


Please wait...

progress bar, please wait

Tell Us WhatYou Think

Please leave your comment below.

AARP Staying Sharp: Keep Your Brain Healthy


Discounts & Benefits

From companies that meet the high standards of service and quality set by AARP.

Walgreens 1 discount membership aarp

Members can earn 50 points per $1 spent on select health & wellness products at Walgreens.

member benefit aarp hear usa

Members save 15% on easy listening devices and more at the HearUSA Hearing Shop.

Eye Med 4 Membership Benefit AARP Discount

Members save up to 60% on eye exams and 30% on glasses at Target Optical.

Membership Benefits Discounts Email Genius

Brain boost? Get AARP email for access to memory exercises & more that help you focus.

Rewards for Good

Your Points Balance:

Learn More

Earn points for completing free online activities designed to enrich your life.

Find more ways to earn points

Redeem your points to save on merchandise, travel, and more.

Find more ways to redeem points