What you need to know about vitamin B12


What you need to know about vitamin B12

They say good things come in small packages and if that’s true, vitamin B12 is a very good thing.  Out of the 13 vitamins needed for human health, this one has the smallest Recommended Dietary Allowance (RDA) amount required at only 2.4 micrograms a day for both males and females, ages 14 and up.  Despite the miniscule amount needed, it has the largest and most complex chemical structure.  In fact, it can be one of the more difficult vitamins to correctly diagnose a deficiency within a person.  Delayed diagnosis can lead to various neurological abnormalities along with other harmful symptoms if left unchecked. 

History of Vitamin B12

As far back as the 1850’s, pernicious (meaning “deadly”) anemia was understood to be caused by the lack of intrinsic factor, a protein made in the stomach lining.  When intrinsic factor is lacking, dietary vitamin B12 cannot be absorbed, leading to pernicious anemia.  Despite this knowledge, the discovery of vitamin B12 would not take place until nearly a century later and meanwhile the condition remained fatal.  It wasn’t until 1926, when researchers George Minot and William Murphy reported that eating large amounts of liver (a rich source of vitamin B12) was effective at treating pernicious anemia.  They were awarded the Nobel Prize for Medicine for their discovery.   Finally in 1948, vitamin B12 was isolated, giving it the unique distinction of being the last vitamin to be discovered. 

Functions of Vitamin B12

Also known by its chemical term cobalamin because it contains the mineral cobalt, vitamin B12 works closely with another water-soluble vitamin folate, as they are dependent on each for activation.  On its own, vitamin B12 is necessary to produce ATP from certain fatty acids, to make red blood cells, DNA, and to maintain the myelin coating which protect nerve fibers. 

What foods is it found in?

An easy way to remember sources of vitamin B12 is that it is found only in foods of animal origin.  As long as a person is eating meat, fish, poultry, milk, cheese, or eggs, they should not be at risk of a vitamin B12 deficiency.  For strict vegetarians, avoiding the development of a deficiency will require either consuming foods fortified with vitamin B12 such as fortified breakfast cereals and fortified soymilk – or taking a vitamin B12 supplement.

Causes of deficiency  

There are numerous ways to become vitamin B12 deficient and several groups of people are prone to deficiency:

·       Older adults

About 10-30% of older adults will have atrophic gastritis which decreases the secretion of hydrochloric acid in the stomach necessary to release vitamin B12 which is bound to protein in food.  Without sufficient hydrochloric acid, vitamin B12 from food sources cannot be absorbed.   However the vitamin can be absorbed from foods fortified with synthetic vitamin B12 and dietary supplements as they are in a free form and do not require any separation process. 

·      Pernicious anemia

This autoimmune disease affects gastric mucosa leading to the inability to produce intrinsic factor, resulting in vitamin B12 malabsorption, despite a person’s adequate intake of the vitamin.   Pernicious anemia is treated with intramuscular or subcutaneous injections of vitamin B12.

·      People with celiac or Crohn’s disease  

Individuals with these conditions may be unable to absorb proper amounts of vitamin B12.  In celiac disease, villi that line the walls of the small intestine are damaged, reducing the ability to absorb many nutrients including vitamin B12.  Crohn’s disease also causes malabsorption issues with vitamin B12.

·      Weight loss surgery

Stomach stapling or surgery to remove part of all of the stomach can cause a loss of cells that secrete hydrochloric acid and intrinsic factor.  Vitamin B12 from food sources are at risk as the absorption rate is dramatically reduced.

·      Strict vegetarians

A person who consumes only food from plant sources (vegan) is automatically at risk for a deficiency.  Consuming foods fortified with vitamin B12, such as breakfast cereals, can help avoid this risk.

·      Frequent use of antacids

A 2013 study in the Journal of the American Medical Association, demonstrated frequent use of antacids were associated with an increased risk of vitamin B12 deficiency.    Antacids are commonly used to reduce stomach acid. Stomach or gastric acid is necessary to release vitamin B12 from dietary sources in order to be absorbed.  When this acid is reduced, they can inadvertently cause malabsorption of vitamin B12

Signs and symptoms of a deficiency

Symptoms of vitamin B12 deficiency can be found in both the circulatory and nervous systems.  Since many of the symptoms tend to be vague and can also be related to other various medical conditions, getting a correct diagnosis by a skilled health professional is crucial to treating the deficiency as soon as possible and to avoid permanent damage.

Circulatory symptoms include:

·      Fatigue

·      Weakness

·      Shortness of breath

·      Pale appearance

·      Heart palpitations

·      Megaloblasticanemia – Anemia characterized by large immature red blood cells in thebloodstream that cannot carry oxygen properly; this occurs in folic acid deficiency and pernicious anemia.

Neurological symptoms include:

·      Tingling and numbness in extremities

·      Abnormal gait and difficulty in maintaining balance

·      Depression

·      Dementia, memory loss or disorientation

Treating a vitamin B12 deficiency

Before vitamin B12 deficiency is diagnosed, the levels must be checked by a blood test.  Normal results are between 200-900 pg/ml (picograms per milliliter).  Homocysteine and methylmalonic acid levels should also be checked as they tend to be elevated when a person is deficient in vitamin B12. Once a person is diagnosed with a deficiency, a physician will determine the route, dosage, treatment timing, and follow-up.  Depending upon what specifically is causing the vitamin B12 deficiency, treatment may include either an intramuscular or subcutaneous dose of vitamin B12, oral supplements or an intranasal remedy.  Before self-diagnosing or trying self-remedies with vitamin B12 supplementation, always consult with your physician to achieve the best results.