Vitamin B12 - What You Need To Know

by Rahul Kapur

Vitamin B12 - What You Need To Know

If you are like many people, you know that vitamins are important and that your diet should include a wide range of them.  But you may not know what all of the individual vitamins do for you or what you risk by failing to get enough of them. Let’s focus on Vitamin B12 for the moment. Vitamin B12 is a water-soluble vitamin that is naturally present in animal products, may be added to other foods, and is readily available as both a dietary supplement and as a prescription medication. Vitamin B12 takes several forms and contains the mineral cobalt, so compounds with vitamin B12 activity are collectively called “cobalamins.”

So what does vitamin B12 do for us?  Our bodies need vitamin B12 for several important bodily functions, including: 

  • proper red blood cell formation
  • neurological activity
  • DNA synthesis

Further, vitamin B12 is an important contributor to systemic processes: 

  • production of cellular energy
  • adrenal gland support
  • nerve and brain regeneration
  • female and male reproductive health
  • metabolism of fat and protein

B12 is commonly known as the “energy vitamin” because it helps to improve your energy and to beat fatigue and exhaustion.  Further, it improves energy by aiding thyroid function and cellular methylation.

How much vitamin B12 do we need? 

Are you getting enough?  Official recommendations for daily intake of vitamin B12 and other nutrients have been published in the Dietary Reference Intakes (DRIs) determined by the Food and Nutrition Board (FNB) at the Institute of Medicine (IOM) of the National Academies.  According to those recommendations, the recommended daily allowance (RDA) of B12 for adults is 2.4 micrograms (mcg) a day. The RDA is the average daily amount that is adequate to meet the nutrient needs of most healthy people.  A standard multivitamin provides 6 mcg, more than enough to meet your body’s daily needs. That said, however, doctors everywhere agree that getting vitamins from food is far preferable to getting them from a vitamin pill.

How does nutrition play a role?

How do you get enough vitamin B12 in your diet?  Like many vitamins, B12 can’t be made by your own body. Instead, it must be obtained from food.  That’s where good nutrition comes in. Rich food sources of vitamin B12  include various kinds of seafood (clams, fish – especially salmon, trout and tuna), red meat (especially beef and beef liver), chicken, eggs, dairy products (milk, yogurt, and cheese), and breakfast cereals and grains to which B12 has been added.  Generally speaking, plants do not make vitamin B12 so a diet that is totally reliant on plant-based foods cannot meet your daily requirements for that vitamin. 

What are the risks of vitamin B12 deficiency?

So what do you risk if you don’t consume enough vitamin B12Some of the key risks of vitamin B12 deficiency are

  • megaloblastic anemia
  • fatigue
  • weakness
  • constipation
  • loss of appetite
  • weight loss

Other serious risks of vitamin B12 deficiency include

  • difficulty thinking and reasoning (cognitive difficulties)
  • memory loss
  • confusion
  • dementia
  • depression
  • difficulty maintaining balance
  • sore mouth or tongue
  • numbness and tingling in the hands and feet 

The neurological symptoms like numbness and tingling in the hands and feet require early diagnosis and treatment to avoid permanent damage

Who is at risk of developing vitamin B12 deficiency?

Are you among those at risk of developing a B12 deficiency?  The National Health and Nutrition Examination Survey reports that it is relatively common, particularly among older people.  Approximately 3.2% of adults over the age of 50 have a seriously low level of B12 level. Further, as many as 20% may have a borderline vitamin B12 deficiency. Other experts rate the incidence of deficiency as being higher than 25%. It’s quite possible that there are millions of people suffering from B12 deficiency who are not even aware of it, especially elderly people and those who don’t eat animal products.

Several distinct groups of people are at risk of developing vitamin B12 deficiency.  Because animal products are high on the list of B12 sources, strict vegans and vegetarians are at high risk for developing a B12 deficiency if they don’t take vitamin supplements.  It’s important for people in those groups to eat fortified breakfast cereals and fortified nutritional yeasts, some of the only sources of vitamin B12 that come from plants, or a good daily vitamin supplement.  Other people who are at risk of vitamin B12 deficiency are people who have had weight-loss surgery because the operation interferes with the body’s ability to extract vitamin B12 from food. People who suffer from health problems that affect the body’s ability to absorb nutrients, like celiac disease or Crohn’s disease can experience B12 deficiency. 

Another disease associated with a vitamin B12 deficiency is pernicious anemia, an autoimmune condition that causes damage to the gastric mucosa and results in gastric atrophy. Indirectly, gastric atrophy can lead to poor absorption of vitamin B12. Untreated pernicious anemia causes vitamin B12 deficiency, leading to megaloblastic anemia and neurological disorders, even if the patient has an adequate dietary intake of vitamin B12.  People who take commonly prescribed heartburn drugs, which reduce acid production in the stomach, also run the risk of vitamin B12 deficiency. That is true because some acid is required to absorb vitamin B12.

Other people who may be at risk of developing a B12 deficiency are older adults because a decrease in production of stomach acid often accompanies aging.  The Institute of Medicine recommends that people over 50 should get extra B12 from a supplement, because they may not be able to absorb enough of the vitamin from food.  

People who need a remedy for serious vitamin B12 deficiency can address the problem in two different ways: by taking weekly shots of vitamin B12 or by taking high daily doses of B12 in pill form.  Generally speaking, a good quality multivitamin should be adequate to compensate for a mild B12 deficiency.

What are the risks of excessive intake of vitamin B12?

The Institute of Medicine (IOM) referenced above has not established an upper limit for vitamin B12 ingestion because it has only low potential for toxicity.  That is due in part to it being a water-soluble vitamin that does not build up in the body.  In Dietary Reference Intakes, the IOM makes the following statement: “no adverse effects have been associated with excess vitamin B12 intake from food and supplements in healthy individuals.”

So now that you know more about the benefits of vitamin B12, as well as the risks associated with B12 deficiency, what changes might you make to your diet to protect yourself?  It’s a question well worth your time to consider.

PLEASE NOTE that the information in this article is not to be used in lieu of medical advice from your doctor. All content found on this website including articles, text, images, audio, videos, or other formats were created for informational purposes only. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment.


Rahul Kapur
Rahul Kapur