Vitamin b12 - How Well is Yours Absorbed?
Vitamin b12 is unique in the b vitamins as it is the only one not found in vegetables.
It is also the only b vitamin containing a metal - cobalt. Foods rich in b12 include liver, kidney, milk, cheese, tempeh, whole grains, eggs and meat.
Vegetarians who do not eat any animal products and no fermented food like tempeh could be deficient in vitamin b12. If in doubt, or you're feeling tired and sluggish, get your blood tested.
Vitamin b12 is absorbed from the gastrointestinal tract, but those with poorly functioning digestive systems, or the elderly, may have trouble absorbing vitamin b12 from food. This is because hydrochloric acid normally secreted from the gastric cells in the stomach in sufficient quantities is required to make the b12 from food available to be bound with intrinsic factor (also secreted in the stomach). This b12 - intrinsic factor complex is absorbed in the small intestine in the presence of calcium.
Those with pernicious anemia will require injections of vitamin b12, as they cannot absorb it from the intestines. Those with poor stomach acid secretion, who still have intrinsic factor available, can still absorb supplements of vitamin b12 as this form of b12 is not bound to protein.
weakness, personality changes, mood changes, abnormal sensations like tingling in the arms and legs. b12 deficiency damages the myelin sheath that covers nerves in the skull, spine, and periphery.
impaired osteoblast activity (osteoblasts involved with bone)
RDA - those over 60 years should get most of their vitamin b12 rda in supplemental or fortified food, due to increased risk of problems absorbing vitamin b12 from food.
For adults 19 years and older the rda is 2.4 mcg/day.
Sublingual vitamin B12 is the most effective way to get this vitamin as a supplement. More information here.
Further information from the Linus Pauling Institute on vitamin b12
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