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Is Subclinical B12 Deficiency Aging Us Prematurely

Friday, May 16, 2014

I did a little research the other day on vitamin B12 for my Advanced Nutrition class at UConn, and I wrote this little blurb for our online discussion.  I thought it was incredibly interesting and something everyone should hear, so I cleaned it up a little and put it on the blog. Because everyone reads my blog.  Everyone.  You aint cool.  

And yes, that means I have a higher standard for my blog posts than I do for my school assignments.  I dont know whether thats a good thing or a bad thing.  But its definitely a thing.

A little background on B12.  Its the one essential vitamin thats only present in animal foods, meaning vegans are shit out of luck (except for maybe supplementing with algae... maybe).  Its present in just about every animal food out there, and especially high in organ meats like liver.  The problem with B12, especially as we age, is that there are a lot of things that have to go right for B12 to be absorbed correctly.  We need enough stomach acid, adequate pancreatic function, proper digestion and absorption in the small intestine... overall theres a lot of room for error, especially in older adults.  Even if were eating enough B12, that doesnt necessarily mean were absorbing it. 

Okay enough of that, here it is...


When learning about B12, I was reminded of an article I read a little while ago about B12 deficiency called B12 deficiency: a silent epidemic with serious consequences. The author makes the case that our definition of B12 deficiency may be set too low, and that we can still see symptoms of deficiency at levels that are now considered normal. Currently in the United States, a serum B12 level of less than 100 pg/ml will get you diagnosed with a deficiency, while a range of 200-900 pg/ml is considered normal. But research indicates that those with B12 levels between 200-350 pg/ml, especially older adults, may still show deficiency sypmtoms.

Why is this important? Because B12 is involved in the nervous system and for myelin sheath formation, one of the most common deficiency symptoms is neurological impairment. This could manifest in several ways, including problems with cognition, decreased mobility, or impaired memory. In the elderly, how do we know whether a decline in cognitive function is due to simple aging or due to a subclinical B12 deficiency? We dont. Especially if were A) not testing for serum B12, and B) our deficiency level is set too low.

Interestingly, Japan has increased their cutoff for B12 deficiency to a serum level of 550 pg/ml (confirmed by Wikipedia)... very much higher than our cutoff of 100 pg/ml. Anyone below that level receives treatment. The Japanese also have lower rates of Alzheimers disease and other dementia compared to us here in the States. Its just an association, but there may be a connection there between higher serum B12 in the Japanese and a lack of cognitive decline.

Based on this information, it would seem prudent to keep an eye on B12 status, especially in the elderly. According to the lecture notes, about 15% of the elderly are B12 deficient; the figures in the study cited above place that number at up to 40%. But we dont know how many reside at the low-normal level (a level that would be considered deficient in Japan). B12 supplementation seems to provide far more potential benefit than risk, so I see no reason why we dont give it a shot in those who are subclinically deficient, especially if we can prevent more serious symptoms if levels were to continue to drop.


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