Written By: Kristen Boye

Vitamin B12, best known for its role in supporting energy, is an essential nutrient found in mostly animal-based foods, such as meat, eggs, and dairy products.

However, Vitamin B12’s health benefits go far beyond supporting energy.

In this article, you’ll learn the basics behind vitamin B12 and its far-reaching health benefits, including:

  • Why B12 deficiency is not just a vegetarian or vegan problem

  • The best food sources of B12

  • The best supplemental forms of Vitamin B12

  • And its many health benefits

B12 Deficiency: Not Just A Vegetarian or Vegan Problem

Due to its prevalence in animal-based foods, most omnivores presume they’re getting enough B12.

However, B12 deficiency or insufficiency is no longer just a vegetarian or vegan problem.

Although B12 deficiency is more common in those who do not eat meat, research has shown up to 26% of the global population is deficient in B12, not just vegetarians and vegans. (1)

Other factors can significantly affect a person’s ability to absorb and metabolize the vitamin B12 they take in from foods and/or supplements.

Some of these include:

  • Age, those over 50 are more prone to B12 deficiency (2)

  • Certain autoimmune conditions (3,4)

  • Digestive issues such as lack of hydrochloric acid (5)

  • Genetic variations (6)

  • Gut health issues, such as SIBO (small intestinal bacterial overgrowth), celiac, or Crohn’s Disease (7,8)

  • Taking certain medications, such as birth control pills or proton pump inhibitors (11)

  • Thyroid health issues

Signs of B12 deficiency may include:

  • Anemia

  • Decreased appetite

  • Diarrhea

  • Fast heart rate

  • Lack of stamina/endurance

  • Memory or cognitive problems (at any age)

  • Mood imbalance

  • Muscle weakness

  • Nerve damage

  • Numbness or tingling in hands and feet

  • Sleep issues

  • Smooth and tender tongue

  • Trouble walking

  • Weight loss (12,13,14)

If you suspect you may have a Vitamin B12 deficiency, your doctor or healthcare practitioner can order a test to check your levels.The list of symptoms above could also be due to a variety of other causes, so it’s always best to check with your doctors when experiencing issues.

Best Food Sources of Vitamin B12

The first step in ensuring you’re getting enough vitamin B12 is to know the best food sources, which include: (15)

  • Organ meats, such as liver

  • Red meats such as beef, lamb, bison, venison, etc.

  • Poultry such as chicken, turkey, quail, duck, etc.

  • Fish and seafood, especially clams and sardines

  • Dairy products

  • Eggs

Plant-based sources of B12 include:

  • Nutritional yeast 

  • Fortified plant milks

  • Fortified cereals and grains

  • Fermented soy products, such as miso and tempeh, may contain small amounts

Since animal products are the best sources of Vitamin B12, many healthcare practitioners recommend vegans or vegetarians take a B-complex or B12 supplement.

Likewise, since vitamin B12 absorption and metabolism may be affected by genetic variations, your practitioner may recommend a specific form of B12 in a supplement, such as methylcobalamin, which bypasses genetic variations.

Talk to your doctor or healthcare practitioner for individual recommendations.

8 Benefits of Vitamin B12 For Physical, Mental, and Emotional Well-Being

Now that you have a better understanding of the basics of Vitamin B12, signs of deficiency, and risk factors, let’s explore eight of its incredible health benefits.

1. Vitamin B12 Supports Blood Function

When we think of blood-building nutrients, most of us think of iron—which is essential. 

However, Vitamin B12 is iron’s best friend as the two work together to support red blood cell formation and function, which allows for proper oxygen flow throughout the body. (16)

Without enough Vitamin B12, a type of anemia known as pernicious anemia can develop, which causes a variety of symptoms and can be life-threatening if not treated. (17)

2. Vitamin B12 Promotes Normal Brain & Nervous System Function

Research has shown Vitamin B12 plays a critical role in normal functioning of the brain and nervous system, including memory, mood, neurotransmitter function, and other cognitive processes. (18,19,20)

Studies have also shown a lack of B12, often coupled with a lack of folate, can result in cognitive symptoms such as memory loss, mood issues, and cognitive decline. (21,22)

More research is needed to understand how vitamin B12 supplementation may affect brain health.

3. Vitamin B12 May Support Endurance Athletes

Endurance athletes tend to have greater needs for certain nutrients due to their intense training schedules and high metabolism.

For example, current research suggests athletes may be more prone to suboptimal levels of specific B vitamins, especially if they are on very restricted diets, have eliminated food groups, have a genetic variation or mutation that hampers the absorption of crucial B vitamins such as folate or B12, or anyone eating no or minimal animal foods. (23,24,25)

Emerging research also suggests endurance athletes may benefit from B-vitamin supplementation for supporting exercise endurance, energy, metabolism, red blood cell function, muscle building, and recovery. (26,27,28)

4. Vitamin B12 Supports A Healthy Pregnancy

Prenatal vitamins contain Vitamin B12 for a reason; it is essential to several aspects of a healthy pregnancy and fetal development, including: (29,30)

  • DNA manufacturing

  • Healthy blood

  • Interacting with folate to possibly help prevent neural tube defects

  • Impaired fetal development

  • Risk of low B12 in the fetus

  • Emerging research suggests B12 deficiency may be linked to the viability of pregnancy, although more research is needed (31)

Therefore, if you suspect a B12 issue and are pregnant or planning to become pregnant, talk to your doctor.

5. Vitamin B12 Helps Fight Fatigue

One of the biggest roles B vitamins play within the body, including B-12, is in producing energy.

Therefore, a lack of B12 is often associated with feelings of fatigue or tiredness, which can range from irritating in someone with a mild deficiency or insufficiency to severe in someone with B12 (pernicious) anemia.

Research shows that getting adequate amounts of B vitamins, including Vitamin B12, is essential for the normal functioning of the body’s energy-production system. Therefore, a lack of B vitamins can negatively impact energy production, resulting in potential metabolic and other health consequences. (32)

6. Vitamin B12 Supports Metabolic Function

In its simplest form; metabolic function refers to the interplay between several organs and systems that support the conversion of food and drink to energy. (33)

Vitamin B12 plays a vital role in metabolic function by supporting the body in converting carbohydrates into glucose which it uses for energy. 

Perhaps this is partially why so many people swear by the power of protein to support metabolism. 

If it comes from an animal source or is fortified, it likely contains B12.

7. Vitamin B12 Supports Hair, Skin, And Nails

Many hair, skin, and nail supplements contain Vitamin B12. 

That’s because a lack of Vitamin B12 has been associated with hyperpigmentation of the skin and nails and even premature gray hair! (34,35)

Fortunately, research has shown getting enough Vitamin B12 may reverse these effects.

8. Vitamin B12 Supports Cardiovascular Function

As you’ve already learned, Vitamin B12 is essential for blood health, which directly affects cardiovascular function.

It’s also been shown to support normal homocysteine levels in the blood, which are related to heart function. (36)

How Much Vitamin B12 Do You Need?

Although individual needs may vary, The National Institutes of Health (NIH) recommends: 

  • 2.4 micrograms (mcg) of vitamin B12 daily for teens and adults over the age of 14

  • 2.6 mcg daily during pregnancy

  • 2.8 mcg daily during lactation

If you have B12 deficiency, genetic variations, or other related health issues, you may require more or less so always check with your healthcare practitioner.

To Recap:

  • Vitamin B12 is an essential nutrient that must be consumed from foods or supplements.

  • Vitamin B12 has many health benefits for the brain, nervous system, metabolism, heart, blood, reproductive system, and more.

  • Animal foods are the best food sources of vitamin B12

  • Vitamin B12 deficiency can affect vegans, vegetarians, and meat eaters

  • Genetic variations, age, certain medications, and pre-existing conditions may impact your ability to absorb vitamin B12

  • Your doctor or healthcare practitioner can order a test to check B12 levels and make individual recommendations about supplementation

If you are healthy and eat a varied diet that includes animal products, you’re likely getting enough vitamin B12.

However, if you have doubts or symptoms, check with your doctor or healthcare practitioner. 

The good news is, if you aren’t getting enough, it’s typically not difficult to get back on track with dietary changes or supplementation.

1 “Vitamin B12 Deficiency”. Nature Reviews Disease Primers.
2 “Vitamin B12 Fact Sheet for Health Professionals”. National Institutes of Health Office for Dietary Supplements.
3 “Correlation Between Vitamin B12 Deficiency and Autoimmune Thyroid Diseases”. Endocrine, Metabolic, and Immune Disorders Drug Targets.
4 “Vitamin B12 Deficiency”. StatPearls. Internet.
5 “Are you getting enough B12?” Harvard Health.
6 “Genetic Variants Associated With Vitamin B12”. Harvard School of Public Health.
7 “Small Intestinal Bacterial Overgrowth: Comprehensive Review of Diagnosis, Prevention, and Treatment Methods”. Cureus.
8 “Are you getting enough B12?” Harvard Health.
9 “How Birth Control Pills Affect Your Nutritional Needs”. Scientific American.
10 “Proton Pump Inhibitor and Histamine 2 Receptor Antagonist Use and Vitamin B12 Deficiency”. JAMA.
11 “Vitamin B12 Deficiency”. StatPearls. Internet.
12 “Vitamin B12 Deficiency”. StatPearls. Internet.
13 “Vitamin B12 Deficiency Anemia”. Johns Hopkins Medicine.
14 “Vitamin B12 Fact Sheet for Health Professionals”. National Institutes of Health Office for Dietary Supplements.
15 “Vitamin B12 Fact Sheet for Health Professionals”. National Institutes of Health Office for Dietary Supplements.
16 “Vitamin B12 Deficiency”. StatPearls. Internet.
17 “Pernicious Anemia”. StatPearls Internet.
18 “B Vitamins and the Brain: Mechanisms, Dose and Efficacy—A Review”. Nutrients.
19 “Vitamin B12 Supplementation: Preventing Onset and Improving Prognosis of Depression”. Cureus
20 “Low Vitamin B12 Levels: An Underestimated Cause Of Minimal Cognitive Impairment And Dementia”. Cureus.
21 “Vitamin B12 Fact Sheet for Health Professionals”. National Institutes of Health Office for Dietary Supplements.
22 “Association between Vitamin B12 levels and cognitive function in the elderly Korean population”. Medicine.
23 “Genetic variants associated with vitamin B12”. Harvard TH Chan School of Public Health.
24 “Association between Different Types of Exercise and Intake of Nutrients including Carbohydrate, Fat, Protein, and B Vitamins in Young Adults”. International Journal of Sport Nutrition and Exercise Metabolism.
25 “Nutrition Assessment of B-Vitamins in Highly Active and Sedentary Women”. Nutrients.
26 “Association between Different Types of Exercise and Intake of Nutrients including Carbohydrate, Fat, Protein, and B Vitamins in Young Adults”. Nutrients.
27 “Thiamin, riboflavin, and vitamins B-6 and C: impact of combined restricted intake on functional performance in man”. The American Journal of Clinical Nutrition.
28 “Nutrition Assessment of B-Vitamins in Highly Active and Sedentary Women”. Nutrients.
29 “Maternal Vitamin B12 Status and Risk of Neural Tube Defects in a Population With High Neural Tube Defect Prevalence and No Folic Acid Fortification”. Pediatrics.
30 “Cobalamin Status from Pregnancy to Early Childhood: Lessons from Global Experience”. Advances in Nutrition.
31 “Vitamin B12 deficiency, infertility and recurrent fetal loss”. Journal of Reproductive Medicine.
32 “Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence”. Nutrients.
33 “Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence”. Nutrients.
34 “Reversible hyperpigmentation of skin and nails with white hair due to vitamin B12 deficiency”. Archives of Dermatology.
35 “Prospective Analytical Controlled Study Evaluating Serum Biotin, Vitamin B12, and Folic Acid in Patients with Premature Canities”. International Journal of Trichology.
36 “The Impact of Homocysteine, Vitamin B12, and Vitamin D Levels on Functional Outcome after First-Ever Ischaemic Stroke”. Biomed Research International.