Deficiency of vitamin B12 can cause a wide range of health problems, many of which can be mistaken for other disorders. For example, elderly people experiencing cognitive decline may be misdiagnosed with Alzheimer's disease, when in reality they are suffering the effects of long-term B12 deficiency.
Deficiency of the vitamin is most often because the body's method of absorbing it is defective, which can result in deadly anemia, sleeping disorders or mental decline. Because B12 is only found in animal foods, vegetarians must be especially careful to supplement their diets with B12 vitamin capsules or injections. Those lacking sufficient levels of the vitamin can easily supplement with oral doses of highly absorbable B12 -- methylcobalamin.
Methylcobalamin is the most active and easily absorbed form of B12. Though the vitamin is available in other forms -- such as cyanocobalamin, hydroxycobalamin and adenosylcobalamin -- the methylcobalamin form is the easiest form for the body to process and utilize.
Though most people generally get adequate levels of methylcobalamin through their diets, if their B12 absorption mechanism is not properly functioning, the symptoms of their vitamin deficiency can be delayed for years, or can be masked as other disease symptoms.
In the elderly, deficiency can cause depression, numbness, pins and needles sensations or a burning feeling, as well as Alzheimer's symptoms. It can also cause a swollen tongue and diarrhea.
In a large, double-blind study, 61 percent of elderly patients exhibiting signs of mental decline completely recovered from their symptoms after supplementing with methylcobalamin. The researchers believed that the 39 percent who did not fully recover had experienced irreversible brain damage as a result of long-term undiagnosed B12 deficiency.
Those suffering from sleep-wake disorder, which includes symptoms such as daytime sleepiness, restless nights and frequent nighttime awakenings, can be treated with 1.5 to 3 mg daily of methylcobalamin. Supplementation can also lead to better sleep quality, daytime alertness, increased concentration and better mood.
Vitamin B12 deficiency is generally treated by supplementing with 2 to 3 mg of methylcobalamin daily for at least one month, followed by daily doses of 1 mg.