Vitamin B12: are there benefits to regular supplementation?

The nutrient cobalamin, more commonly known as vitamin B12, is essential for the function of critical cells in the body, not least the brain and blood. Deficiencies in the vitamin generally only occur in two people: vegans, and those with pernicious anemia (a rare autoimmune disorder). Vegans might not get enough from their diet, and pernicious anemia sufferers can't absorb it. Other than these two groups, are there any vitamin B12 benefits that can be gained by taking supplements?

Psoriasis


Psoriasis is an autoimmune disorder of the skin that results in itchy patches. A recent study has shown that vitamin B12 mixed with avocado oil and applied to the skin provided an advantage in treatment over other topical solutions. This research is still preliminary, however.


Alzheimer's


In a large study that followed elderly people over the course of many years, it was found that those with low blood levels of vitamin B12 had greater degrees of brain atrophy as they aged, which is connected such dementia diseases as Alzheimer's. Elderly people are at greater risk of developing B12 deficiencies, as their stomach acid reduces in ability to absorb the nutrient.


Cyanide Antidote


The most common and useful benefit of vitamin B12 is as an antidote for cyanide poisoning. This is done by using the form of B12 called hydroxocobalamin, and is a very effective treatment for cyanide toxicity.


Supplement?

In general, it is not necessary to supplement with vitamin B12 unless you are in one of the aforementioned risk groups: vegans and pernicious anemia, and possibly elderly as well. B12 is found in animal foods, such as fish, poultry, meat, dairy, etc., and so as long as you eat these foods regularly, you are probably not in danger of being deficient. The benefits of B12 are not worth adding a supplement to your diet unless you suspect you may be deficient.

References:

http://www.nlm.nih.gov/medlineplus/ency/article/002403.htm

http://www.nlm.nih.gov/medlineplus/druginfo/natural/926.html