Everything You Need To Know About Vitamin B-12

Everything You Need To Know About Vitamin B-12


ConsumersCompare.org Staff

Updated on Aug 08, 2019

What Is Vitamin B-12?

Vitamin B-12 is the most complex of the B-vitamin family. It has different forms: cyanocobalamin, hydroxocobalamin, adenosylcobalamin and methylcobalamin, with only the last two being involved in metabolic functions in the human body. Hydroxocobalamin is produced by bacteria and is used to treat cyanide poisoning. [1]

The US Food and Drug Administration (FDA) has set the Recommended Daily Value (RDV) for B-12 at 6 mcg (micrograms). [2] It is essential that the required amount of this very important vitamin is obtained, as it is needed for proper functioning of the brain and nervous system as well as for the synthesis of DNA and RNA.

The most common absorption mechanism of B-12 from whole foods is to first unbind the vitamin from proteins; this reaction is carried out in the stomach by hydrochloric acid and gastric protease. If vitamin B-12 is taken as a supplement or obtained from fortified foods this step is not necessary, as it is already in the free form. The second step in this process is combination with glycoproteins formed in the stomach to make a compound absorbed by the small intestines.

The human body stores several years’ worth of vitamin B12 in the liver, so low levels in the body are rare. Decreases in vitamin B12 levels are more common in the elderly, HIV-infected persons, and vegetarians. (MayoClinic.org) [2]

People with gastrointestinal disorders and those who have had gastrointestinal surgery are most likely to suffer from vitamin B-12 deficiency. Other persons at risk of deficiency are pregnant and lactating women who are vegetarians (or vegans), and those suffering from pernicious anemia.

When sufficient amounts of vitamin B-12 are not obtained, vitamin B-12 deficiency results, characterized by anemia (a deficiency of red blood cells, the oxygen carriers), fatigue, weakness, constipation, loss of appetite, and neurological changes such as numbness and tingling in the hands and feet. Other symptoms include depression, dementia, memory loss, and the inability to maintain one’s balance. [3]

Vitamin B-12 may be obtained from whole foods listed below, fortified foods, and dietary supplements.

back to menu ↑

Facts About Vitamin B-12

  • Fungi, plants, and animals are incapable of producing vitamin B-12. Only bacteria or single-celled microorganisms have the enzymes necessary to fully synthesize vitamin B-12.
  • Vitamin B-12 is also known as cobalamin.
  • Vitamin B-12 can only be produced commercially through bacterial fermentation.
  • Vitamin B-12 is the largest and most complicated of the B vitamin in terms of structure.
  • All the forms of vitamin B-12 are red, due to the cobalt-corrin complex present.
  • Feces is a very rich source of vitamin B-12; therefore dogs, cats and rabbits eat it. [1] [3]
back to menu ↑

Foods Containing Vitamin B-12

Vitamin B-12 may be obtained from a variety of whole foods, such as:

  • beef tenderloin
  • beef and chicken liver
  • veal
  • turkey
  • some seafood: salmon, herring, mackerel, sardine, tuna, trout, crabmeat, fish eggs, clams
  • yogurt
  • milk

More processed sources of the vitamin include fortified breakfast cereals, energy bars, soy products and nutritional yeast.

Vitamin B-12 is also available as a dietary supplement, either as an over-the-counter multivitamin or as an intravenous prescription. Supplemental forms of the vitamin are cyanocobalamin, methylcobalamin, and adenosylcobalamin, while as a prescription medication it is in the form of cyanocobalamin and hydroxocobalamin to be administered as an injection. There is also a gel formula, which is administered in the nasal passage as an alternative to the injection.[4]

NOTE: From TheVeganSociety.com: “The only reliable vegan sources of B12 are foods fortified with B12 (including some plant milks, some soy products and some breakfast cereals) and B12 supplements. Vitamin B12, whether in supplements, fortified foods, or animal products, comes from micro-organisms.” [5]

back to menu ↑

Benefits of Vitamin B-12

Heart Health

Chief among the numerous benefits of vitamin B-12 is maintaining a healthy heart and reducing heart disease. Vitamin B-12 reduces the homocysteine levels, a contributing factor in heart disease.

Energy Maintenance in the Body

Vitamin B-12 reduces symptoms such as fatigue and weakness.

Possible Aid in Neurological Maintenance

Additionally, vitamin B-12 may help in the treatment of neurological diseases as well as help to enhance the normal functioning of the nervous system. Vitamin B-12 is needed for the synthesis of certain compounds which are critical in dealing with depression and mood regulation.

Maintains Healthy Hair, Skin, Nails

Vitamin B-12 enables the production of cells. It alleviates symptoms associated with skin conditions such as eczema and psoriasis.

Blood Health

Vitamin B-12 is needed for the production of red blood cells, reducing the risk of anemia.

Fetal Genetic Development

A very important function of vitamin B-12 is that it is needed for the synthesis of DNA, the genetic building block of all newborns. It is therefore vital for the development of healthy, normal growth in infants. This is why pre-natal vitamins contain vitamin B-12 and are recommended by most obstetricians during pregnancy and nursing.[3] [4]

back to menu ↑

Is Vitamin B-12 Ever Bad For You?

The Institute of Medicine of the National Academies has not set an upper intake limit for vitamin B-12 as it has very little potential to be toxic and has no adverse effects even when taken at doses in excess of its recommended daily intake. Two trials (NORVIT and HOPE 2) conducted indicate that at doses well over the RDV for extended periods of time there were no adverse effects experienced. The NORVIT trial had participants on a dosage of 0.4mg for 40months and HOPE 2 trial utilized a dosage of 1mg for 5yrs; no adverse reactions were reported.[3]

Age/Gender/Condition Recommended Daily Value (RDV)
infants to 12 months 0.4 – 0.5 mcg
children 1- 8 years 0.9 – 1.2 mcg
Youth 9 – 13 years 1.8 mcg
14 years and up 2.4 mcg
Pregnant 2.6 mcg
Lactating 2.8 mcg

Currently there is no evidence of adverse reactions—aside from direct allergy to B-12 or to cobalt—associated with intake of vitamin B-12 either from food sources or dietary supplements. But there are a few recommended precautions.

One precaution is regarding interactions with other drugs; vitamin B-12 reacts with Chloramphenicol, an antibiotic; the reaction causes a reduction in the formation of red blood cells. Other drug interactions are with Prilosec, Zantac and Metformin; all decrease the absorption of vitamin B-12, thereby increasing the possibility of vitamin B-12 deficiency. The Mayo Clinic adds a few more items to that list of substances that interfere with B-12 absorption. [6]

The other precaution involves pre-existing medical conditions. The Mayo Clinic urges caution with B-12 in people with the following conditions (detailed on the link): [6]

  • Heart concerns
  • Hypertension (high blood pressure)
  • History of cancer
  • Skin disorders
  • Genito-urinary concerns
  • Gastrointestinal concerns
  • Blood disorders
  • Low potassium levels
  • History of gout
  • Leber’s disease: may lead to damage of the optic nerve and eventually blindness. [7]
back to menu ↑

How To Minimize Exposure

There is no real need to minimize one’s intake of this very important vitamin, though gaining it through food sources is better for the body as a whole.

back to menu ↑

Should You Worry About Vitamin B-12?

Aside from the precautions above, there is no need for otherwise healthy individuals to worry about their B-12 intake.

back to menu ↑

Final Thoughts

Vitamin B-12 is very important to the overall health and well-being of an individual, with functionality in DNA synthesis, formation of red blood cells, cardiovascular maintenance, brain function, and nerve function.

It is highly recommended that adequate intake of this vitamin be obtained by eating foods rich in vitamin B-12. For people who are vegetarians or vegans, it is highly recommended that they incorporate a supplemental form of this vitamin in their diet, as most of the foods rich in this vitamin are meat sources.

Persons suffering from particular diseases such as pernicious anemia or any sort of gastrointestinal disorder should ensure that they obtain vitamin B-12 as an intravenous dietary supplement, since absorption of B-12 is severely curbed in these instances. Your health care provider should be fully informed of any gastrointestinal problems, as well as any previous surgeries done, so that the right type of this vitamin B-12 will be administered.

Due diligence should also be exercised when taking certain medications in conjunction with vitamin B-12, due to its propensity to interact with some drugs—these interactions may result in vitamin B-12 deficiency and serious health effects. Although there have been no adverse effects associated with high intake of vitamin B-12 in healthy individuals, from either food sources or supplements, precautionary measures should still be taken as cases of allergic reactions have been reported.

If you are pregnant or breastfeeding it is critical that you discuss with your health care provider the best option available for obtaining the correct amounts of vitamin B-12, as deficiency may result in serious health problems in the fetus or newborn.

Top Rated
Weight Loss Solutions in 2022

#1 Rated Diet Program #1 Rated Diet Pill #1 Rated Online Diet Plan

How does it work?
How does it work? Follow 30 to 90 day weight loss program, while taking PS1000 Metabolic Burst supplement. PS1000 allows you to lose more weight and reach goals faster than most on weight loss programs. Fat burner, fat blocker, appetite suppressant, and energy booster in one pill. Use it alone or in combination with an eating plan. Best diet pill on a market. Perfectly portioned and convenient meals take the guesswork out of the successful weight loss.
Who is it for?
Who is it for? People who are dedicated in making lifestyle changes, learn healthy eating habits and want to use diet supplement to help speed up the process. People who want help to curb their appetite, get more energy, and burn more fat. People who want to cook their own meals and learn healthy eating habits.
  • Best diet supplement
  • Customizable menus
  • Good quality food
  • Meals are tasty
  • Support community
  • Flexibility in food choices
  • Mobilizes fat for fuel
  • Fast results
  • Burns stored fat
  • Suppresses appetite
  • Money Back Guarantee
  • Best weight loss pill
  • Burns stored fat
  • Suppresses appetite
  • Blocks fat production
  • Money-back guarantee
  • Free shipping
  • Best weight loss program
  • Fully customizable
  • Huge recipe database
  • Support community
  • Great weight loss results
  • Low price
  • Must prep Food
  • Must eat 5 times a day
  • Contains caffeine
  • Ships only to certain countries
  • No shortcuts
  • Lack of maintenance plan
Includes supplement
Includes supplement
Food Recipes
Food Recipes
Health Coaches
Health Coaches
Phone support
Phone support
Email Support
Email Support
Price $1.87/day $69.95 $1.99/to start

*Please keep in mind that with any diet or weight loss program, individual results will vary.

This content is strictly the opinion of ConsumersCompare.org and is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of medical advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither ConsumersCompare.org nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement or lifestyle program.

Read full Medical Disclaimer here.

Compare items
  • Reviews,774 (0)