SAN FRANCISCO (KCBS RADIO) -- Could your "healthy" vitamin B12 levels still be putting you at risk for cognitive decline? A new UCSF-led study reveals that even when B12 levels are within the normal range, older adults may still experience subtle neurological and cognitive impairments, such as slower brain function and damage to vital brain structures.
The findings challenge current health standards and raise important questions about how much B12 is truly needed to preserve brain health as we age, lead author Alexandra Beaudry-Richard told KCBS Radio's Bret Burkhart on this week's episode of "As Prescribed."
"What we show in our study is that we may need more B12 than we thought for neurological function," said Beaudry-Richard.
The conventional wisdom has been that B12 deficiency is only a concern for those with levels below 148 picomoles per liter. However, this standard was created based on population averages, not on whether lower levels of B12 might cause neurological or cognitive symptoms.
"Our question was whether we could detect some symptoms in people above that threshold," Beaudry-Richard explained.
The study found that even when B12 levels were technically "normal," cognitive slowdowns and changes in brain structure were still detectable. The findings suggest that the current threshold for B12 deficiency might be too low to prevent neurological damage in older adults.
"We did see that at those lower levels, there was impairment in the brain's ability to conduct the information fast, but also some changes in the structure that we could see on imaging and brain function that we could detect with cognitive testing," said Beaudry-Richard. "There are some cases reported of people experiencing B12 deficiency symptoms, but since their levels in the blood might be within the current normal range, their doctor may not advise supplementing in B12."
Vitamin B12 is known for its role in cell replication and red blood cell production, but its importance goes far beyond that. The research team discovered that insufficient B12 can damage the brain's white matter — the crucial nerve fibers that allow different brain areas to communicate.
"And so if you have problems in your white matter, you may notice slower conductivity in your brain, which is so important for all rapid functions like thinking, and moving," said Beaudry-Richard. "One thing that we notice in B12 deficiency is people can have a hard time with their balance, with their walking, but also with their thinking and higher neurological processes. So it affects pretty much all of brain function."
Older adults face a unique set of challenges when it comes to Vitamin B12 absorption. Beaudry-Richard pointed out that "as we age, absorbing B12 from food can be more difficult," due to changes in the digestive system and the use of medications that interfere with nutrient absorption. These issues, along with the fact that neurons become more vulnerable as we age, could make older adults more sensitive to low B12 -- even if their blood levels still fall within the "normal" range.
The study suggests that what we currently consider "healthy" B12 levels may not be sufficient to protect brain function, particularly as we age. It also calls into question whether the existing thresholds for B12 deficiency need to be reevaluated.
"We do recommend when people experience foggy brain difficulty with cognition, with walking as well, that they can discuss that with their doctor and maybe have their blood levels checked and consider food intake adjustments or supplements," said Beaudry-Richard. "It is important as we age to really optimize all the factors in order to preserve brain function."
Listen to this week's "As Prescribed" to learn more. You can also listen to last week's episode to learn why advanced prostate cancer is on the rise in California, here.
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“As Prescribed” is sponsored by UCSF.