This article originally appeared on this website in August of 2013.
Vitamin B12 is your basic foundation vitamin. It’s not sexy or miraculous, but this workhorse nutrient is responsible for a host of essential health functions. Everyone needs it!
Most important among B12’s functions, is the task of perfect cell duplication to stave off the ravages of aging, since it is needed to form DNA. It also helps maintain healthy nerve cells and red blood cells.
Most of us get the B12 we need from animal foods: red meat, fish and dairy products. Little or no B12 is found in plant products.
B12, also known as cobalamin, is absorbed into your system when stomach acid breaks down the protein and combines with a substance called intrinsic factor so it can be absorbed through the digestive tract.
Although vitamin B12 deficiency is fairly rare in healthy adults, it is common in strict vegetarians who eat no animal products, in people with digestive system disorders that limit the absorption of the nutrient and in elderly people whose stomach acid production has dropped.
At any age, other symptoms of B12 deficiency can include weight loss, lack of appetite and constipation. (1, 7, 8) Other common symptoms can include difficulty walking, confusion, irritability and mild depression.
Sometimes the only symptom of that deficiency is a barely noticeable decrease in cognitive function. Over time, if the deficiency is not reversed, anemia and dementia that looks very similar to Alzheimer’s disease can develop.
That’s why a simple blood test for B12 level is essential, especially in someone who is elderly and in whom memory loss has been noticed. For all of those people, experts say, B12 supplementation is crucial.
The happy news is that B12 supplementation, usually in the form of B12 injections in the beginning, will often significantly improve or even reverse the condition, says neurologist Allen Josephs, M.D., author of Memory Loss is Not Inevitable (Common Sense Publishing, 2007)
B12 supplements are also important for people who take certain types of prescription medications, especially for people with Type 2 diabetes, says Hyla Cass, M.D., author of Supplement Your Prescription (Basic Health, 2007).
Metformin, a commonly prescribed prescription medication for Type 2 diabetes (once known as adult-onset diabetes), depletes B12 reserves in the human body, says Dr. Cass. For these people, who are often elderly and subject to digestive system-related B12 shortfalls, B12 supplementation is essential, says Dr. Cass. She recommends 200 to 500 mcg daily, with safe dosages up to 1,000 mcg. These quantities are far larger than the RDA of 2.4 mcg, but Dr. Cass advocates larger dosages because they provide more absorbable quantities of B12 and there are no known risks of higher dosages.
Research suggests that 10 to 30% of patients taking Metformin have evidence of reduced vitamin B12 absorption.
B12 shortfalls often occur in people with chronic gastric reflux because they suppress the production of the hydrochloric acid in the stomach that starts the B12 absorption cycle.
And finally, how B12 levels can contribute to elevated homocysteine levels which increase the risk of heart attack, stroke and other cardiovascular diseases. While research is not yet conclusive, there is some evidence that B12 supplements help lower homocysteine levels and thereby reduce the risk of cardiovascular disease.
The U.S. government’s Recommended Daily Allowance (RDA) for B12 is on 2.4 mcg a day for adults, a level that is easily achieved with normal eating patterns.
For example, says the National Institutes of Health’s Office of Dietary Supplements, most fortified breakfast cereals contain the RDA of B12. Better, yet, get your B12 with a serving of clams (84 mcg), beef liver (47.9 mcg) trout (5.4 mcg ), salmon (4.9 mcg ) or lean beef (2.4 mcg).