The absorption of Vitamin B-12 is governed by the intrinsic factor, secreted from parietal cells of the stomach wall as a normal part of gastric juice. A failure in any stage in the absorption of the vitamin can render it unavailable. For instance, one third of people over 60 who no longer secrete gastric acid are unable to absorb Vitamin B-12 from food because they are unable to split B-12 from the protein complex to which it is attached. If the gastric juice of a person lacks the intrinsic factor necessary for absorption of Vitamin B-12, there is no uptake of the vitamin at all from the amounts normally provided in food. However, if amounts about 1000 times the normal dosage are given, sufficient amounts to meet the needs of an individual may pass through the wall by diffusion.
The efficiency of absorption appears to diminish with increase in age, with a pyridoxine deficiency resulting from a decreased synthesis of intrinsic factor, with an iron inadequacy and in hypothyroidism.
Considering the multiple factors which may inhibit the absorption of the vitamin, researchers have considered an alternate route of absorption. One route considered is sublingual, the second most rapid route next to direct injection of the substance into the body.
One tablet daily, or more as directed by a doctor. Dissolve in mouth under tongue, use as a lozenge, chew or swallow whole.
Each tablet contains:
Vitamin B-12 (cyanocobalamin) 1000 mcg.
Folic acid 400 mcg.
Other ingredients: mannitol, natural cherry flavor.