Vitamin B12 goes through acrobat-like moves for
crucial reactions in the body, new research finds.
Vitamin B12 bends over backwards for your health and now, for the first
time, scientists have produced 3-D images of it in action.
University of Michigan and Massachusetts Institute of Technology (MIT)
researchers have created computer-generated 3-D ribbon diagrams of vitamin B12
(and other molecules) in action as it performs its role in transferring methyl
groups — a crucial reaction in the body.
Methyl group transfer is an essential vitamin B12 function needed for
the maintenance of the central nervous and cardiovascular systems, as well as
the conversion of food into energy. It also occurs in the cells of
bacteria that reside in our guts (and in the guts of cows and other animals),
enabling gases such as carbon dioxide and carbon monoxide to be detoxified and
eliminated.
B12 is already known as the biggest and most structurally complicated
vitamin, but this research takes that knowledge a step further—illustrating the
vitamin’s elaborate, acrobatic, “molecular juggling”. The research serves to
better understand how vitamin B12 twists and contorts itself to perform its
essential-for-life functions.
The research may also potentially play a role in the development of new
alternative renewable energy sources using methyl group transfer.
Vitamin B12 represented in action as a full 3-D ribbon
diagram with twists and fold.
How much vitamin B12 dietary intake is needed daily? The established Daily
Value (DV) for B12 is 6 micrograms. Normally, people should be able to obtain
these amounts easily enough from animal products such as meat, shellfish, eggs,
milk, and cheese. However, as people get older, they may lose production
of enough digestive juices necessary to free sufficient B12 that is complexed
in foods. Absorption may be further complicated by failure of cells of the
stomach lining to secrete intrinsic factor, a protein necessary to bind to B12
enabling absorption.
Groups that may want to consider taking a B12 supplement because of
decreased absorption are aging adults, people with pernicious anemia, and
people with decreased levels of stomach acidity (achlorhydria) or
gastrointestinal disorders. These groups should check with their doctors about
having routine blood tests to check vitamin B12 status. Because of vitamin
B12 only being in animal-derived foods, vegetarians may need to include B12
supplements or fortified foods in their diet to ensure adequate intake.
Vitamin B12 is available in several forms including cyanocobalamin,
methylcobalamin, and adenosylcobalamin. Because vitamin B12 is the only
metabolite known to contain cobalt, they are known collectively as cobalamins.
As a supplement, B12 is often provided as cyanocobalamin because of its
relative stability and safety profile. Because the stability and safety of
cyanocobalamin is well established, the supplement is often used even as a
placebo in clinical trials.
Enough vitamin B12 intake daily supports a healthy brain, nervous system,
heart, as well as cell metabolism, but can one get too much? Studies have found
no known toxicity even when provided in extremely high doses (e.g. 1 mg per day
for a year). For this reason, there also has been no Tolerable Upper intake
Level (UL) set to distinguish the amount that may cause adverse effects.
According to the Institute of Medicine (IOM), “no adverse effects have been
associated with excess vitamin B12 intake from food and supplements in healthy
individuals”.
Recently, one
study suggested that older adults taking large doses of vitamin B12 may be
supporting memory and thinking as they age.
References
Horne BD et al. Relation of Routine,
Periodic Fasting to Risk of Diabetes Mellitus, and Coronary Artery Disease in
Patients Undergoing Coronary Angiography. Am J Cardiol. 2012;xx:xxx.
doi: 10.1016/j.amjcard.2012.01.379.
Horne BD, et al. Usefulness of
routine periodic fasting to lower risk of coronary artery disease among
patients undergoing coronary angiography. Am J Cardiol. 2008. doi: 10.1016/j.amjcard.2008.05.021
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