Vitamin B12 Benefits, Deficiency, Foods and Supplements - Dr. Axe

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Vitamin B12 Benefits That You’re Probably Missing


Vitamin B12 benefits - Dr. Axe

Are you struggling with fatigue, low energy levels, mood changes and a lack of focus? This can be a sign that you’re dealing with a vitamin B12 deficiency. If that’s the case, you’re not alone — and something you want to correct considering the abundance of vitamin B12 benefits.

Up to 40 percent of people may have low levels of vitamin B12, which is an issue that needs to be addressed because this is an essential vitamin for the production of red blood cells and DNA, not to mention all the vitamin B12 benefits it provides. 

Vitamin B12 deficiency is thought to be one of the leading nutrient deficiencies in the world, with a 2004 study showing that it’s a major health concern in many parts of the world, including the U.S., India, Mexico, Central America, South America and certain areas in Africa.

This is a big deal because B12 plays an important role in so many body functions, which is exactly why it’s critical that we get enough vitamin B12 foods in our diets.

So what does it do? This essential nutrient affects your:


  • mood
  • energy level
  • memory
  • heart
  • skin
  • hair
  • digestion
  • and more

It is also an essential vitamin for:

  • addressing adrenal fatigue
  • improving pernicious anemia and megaloblastic anemia
  • benefiting multiple metabolic functions, including enzyme production, DNA synthesis and hormonal balance 
  • maintaining healthy nervous and cardiovascular systems

Because of its wide-reaching roles within the body, a deficiency in this essential vitamin can lead to a range of  symptoms, including:

  • chronic fatigue
  • mood disorders like depression
  • chronic stress or feeling run down

What Is Vitamin B12?

Vitamin B12 actually exists in many forms, and it contains the mineral cobalt, which is why compounds with vitamin B12 are collectively called cobalamins. Two forms of B12 that are active in human metabolism are methylcobalamin and 5-deoxyadenosylcobalamin.

Vitamin B12 benefits the central nervous system in many important ways. It helps maintain the health of nerve cells — including those needed for neurotransmitter signaling — and helps form the protective covering of nerves, called the cell’s myelin sheath.

This means that when B12 levels are low, almost every cognitive function can suffer.

It also helps with digestion and heart health, so a deficiency can lead to both digestive disorders and an increased risk for heart disease. It can come in food sources, hydroxocobalamin vitamin B12 injections or as an intramuscular vitamin.

The National Institute of Health’s (NIH) Dietary Office estimates that somewhere between 1.5 percent to 15 percent of people in the U.S. are deficient in vitamin B12.

Other studies, like one published in the American Journal of Clinical Nutrition in 2000, indicate that this number might be even higher, with up to 39 percent of the population possibly suffering from a vitamin B12 deficiency.

Vitamin B12 Benefits

Wonder how vitamin B12 functions as a health-promoting vitamin? Vitamin B12 functions as a beneficial substance in the following ways:

1. Helps Maintain Energy Levels

Vitamin B12 benefits your metabolism because it’s needed to convert carbohydrates into useable glucose in the body. Glucose from carbohydrate foods is used as a form of energy, so this is the reason why people with deficiencies often experience fatigue.

Research shows that vitamin B12 is also needed for neurotransmitter signaling that helps your muscles contract and gives you energy to go about your day without feeling tired and run down.

People often wonder whether vitamin B12 benefits weight loss. Because a deficiency can lead to sluggishness, chronic fatigue, and mood and appetite changes, it can be hard to lose or maintain weight with these symptoms.

It’s not that increasing your vitamin B12 levels alone will make you lose weight, but correcting a deficiency can boost your energy levels and regulate your appetite so you can continue your health routine.

2. Helps Prevent Memory Loss and Lowers Risk of Neurodegenerative Disease

A vitamin B12 deficiency may cause various neurologic and psychiatric disturbances. Because of its role in nerve health and neurotransmitter signaling, studies indicate that vitamin B12 benefits cognitive function and is used to lower the risk of neurodegenerative diseases, including Alzheimer’s disease and dementia.

A systematic review published in International Psychogeriatrics examined 43 studies investigating the association of vitamin B12 and cognitive impairment or dementia and 17 studies reporting the efficacy of vitamin B12 therapy for these cognitive conditions.


Researchers found that low vitamin B12 levels are associated with Alzheimer’s disease, vascular dementia and Parkinson’s disease. On top of this, B12 supplements were effective in correcting a biochemical deficiency and improved cognition in patients with pre-existing vitamin B12 deficiency.

3. Boosts Mood and Helps the Nervous System to Properly Function

One of the most researched vitamin B12 benefits is its ability to help in healthy regulation of the nervous system, including reducing such mood disorders as depression and anxiety.

Studies highlight that vitamin B12, along with folate, is needed as a major determinant of one-carbon metabolism, which produces the compound called SAM-e (S-adenosyl methionine). SAM-e is crucial for neurological function, dealing with stress and mood regulation.

Vitamin B12 is also needed for concentration and cognitive processes, such as learning, so a deficiency can result in difficulty focusing and an increased risk for attention disorders.

4. Plays a Role in Maintaining Heart Health

Vitamin B12 benefits cardiovascular health in several ways, which is important considering the fact that heart disease is currently the No. 1 cause of death worldwide.

Vitamin B12 helps reduce elevated homocysteine levels, which is now considered a major risk factor for heart disease. Homocysteine is an amino acid, and its levels in the blood are influenced by blood levels of B-complex vitamins, including B12.

Vitamin B12 helps protect against heart disease like a heart attack or stroke by lowering high homocysteine levels in the blood. There is also some evidence that B12 can help control high cholesterol and high blood pressure levels.

B vitamins are also able to control atherosclerotic diseases, in which someone experiences a dangerous buildup of plaque in the arteries.

5. Needed for Healthy Skin and Hair

Vitamin B12 is essential for healthy skin, hair and nails because it plays a major part in cell reproduction. Research suggests that vitamin B12 boosts skin health by reducing redness, dryness, inflammation and acne blemishes — and can be applied to the skin for psoriasis and eczema.

It can also reduce hair breakage and help nails become stronger.

Vitamin B12 benefits

6. Aids in Digestion

Due to its role in helping with digestive enzyme production, B12 is needed to support a healthy metabolism and the breakdown of foods within the stomach.

One of the ways that vitamin B12 benefits digestion? It’s proven to help foster healthy bacteria within the gut environment.

The elimination of harmful bacteria in the digestive tract — and simultaneously the presence of beneficial bacteria — is what prevents digestive disorders like inflammatory bowel disease or candida.

7. Needed for a Healthy Pregnancy

Vitamin B12 is needed to create nucleic acid, or DNA — the basic genetic material that’s used to create the entire body. Therefore, the nutrient is not only a key nutrient for growth and development, but a vital component of a healthy pregnancy.

Vitamin B12 also interacts with folate in the body, so it may help lower the risk of birth defects, such as neural tube defects. When a pregnant woman’s B12 supply is low, the folate that’s needed for DNA synthesis remains trapped, and cell replication is impaired.

Studies report a two- to four-fold increased risk of neural tube defects with low vitamin B12 status.

8. May Help Prevent Cancer

Vitamin B12 supplementation is now being studied as a way to help lower the risk of certain kinds of cancers, especially when taken with folate.

Some preliminary research shows that vitamin B12 benefits the immune system enough to potentially help prevent cancer, including cervical, prostate and colon cancers. A study published in the International Journal of Cancer found that low B12 levels may increase the risk of gastric cancer.

Research from 1999 found that B12 status may influence breast carcinogenesis, making it a possible risk factor for breast cancer prevention.

9. Helps Produce Red Blood Cells and Prevent Anemia

Vitamin B12 is needed to help produce a healthy level of red blood cells. It helps prevent a type of anemia called megaloblastic anemia, also known as vitamin B12 deficiency anemia, which results in symptoms like chronic fatigue and weakness.

Research published by Mayo Clinic indicates that a number of individuals with B12 deficiency may present with classic megaloblastic anemia, a blood disorder that occurs when bone marrow produces large, abnormal red blood cells or megaloblasts.

An autoimmune disorder called pernicious anemia is a type of megaloblastic anemia that occurs when the body isn’t able to absorb vitamin B12 properly. Reports describe treatment for pernicious anemia involving therapeutic doses of B12, either through intramuscular injections or orally.


Animal foods are the best food sources of vitamin B12, including:

  • organic, grass-fed dairy products
  • cage-free eggs
  • grass-fed meat
  • wild-caught fish
  • organic poultry
  • organ meats

According to the NIH, plant foods do not naturally contain vitamin B12 unless they are synthetically fortified.

Vitamin B12 can be found to some degree in fortified plant foods like nutritional yeast, fortified grain products and algae sea vegetables. However, most of these are not thought to be nearly as absorbable as natural animal sources.

Although the exact rate of absorbability depends on the person’s digestive health, here are the top food sources that provide vitamin B12:

  1. Beef liver: 1 ounce: 20 micrograms (over 300 percent DV)
  2. Sardines: 3 ounces: 6.6 micrograms (over 100 percent DV)
  3. Atlantic mackerel: 3 ounces: 7.4 micrograms (over 100 percent DV)
  4. Lamb: 3 ounces: 2.7 micrograms (45 percent DV)
  5. Wild-caught salmon: 3 ounces: 2.6 micrograms (42 percent DV)
  6. Nutritional yeast: 1 tablespoon: 2.4 micrograms (40 percent DV)
  7. Feta cheese: 0.5 cup: 1.25 micrograms (21 percent DV)
  8. Grass-fed beef: 3 ounces: 1.2 micrograms (20 percent DV)
  9. Cottage cheese: 1 cup: 0.97 microgram (16 percent DV)
  10. Eggs: 1 large: 0.6 microgram (11 percent DV)
Top 10 vitamin B12 foods - Dr. Axe

B12 Deficiency

Vitamin B12 deficiency can be hard to detect, especially considering how common the symptoms of a vitamin B12 deficiency can be, such as feeling tired or unfocused.

Symptoms may include:

  • Constantly feeling tired or chronic fatigue
  • Muscle aches and weakness
  • Joint pain
  • Difficulty breathing or shortness of breath
  • Feeling dizzy
  • Poor memory
  • Inability to concentrate well
  • Mood changes, like increased depression and anxiety
  • Having abnormal heart problems, such as palpitations
  • Poor dental health, including bleeding gums and mouth sores
  • Digestive problems like nausea, diarrhea or cramping
  • A poor appetite
  • A more serious deficiency can also cause a form of anemia called pernicious anemia, a serious condition that can cause memory loss, confusion and even long-term dementia.

Who is most at risk for having a deficiency?

  • Older adults who tend to have impaired digestion are one of the most susceptible populations. This is because older people tend to produce less stomach acid that is needed to convert the vitamin properly.
  • People who don’t eat meat
  • Smokers are at higher risk because nicotine can block absorption.
  • Alcoholics
  • People with anemia
  • People with digestive disorders, like celiac or Crohn’s disease

Supplements and Dosage

Vitamin B12 can be taken in tablet form, drops that you place under the tongue (called sublingual B12), oral spray form, as gel formulations or even in the form of injection.

You can use any of these types of vitamin B12 supplements, but make sure you choose a high-quality product from a reputable source. If you are curious about B12 injections, talk to your doctor about confirming a deficiency and how to go about this process.

Keep in mind that sometimes older adults do better supplementing with drops and oral spray forms of B12 because they have trouble with the absorption of the vitamin in the stomach.

For adults who are looking to boost their B vitamin levels with something other than whole foods, take B12 as part of a whole foods-based B-complex supplement or a high-quality, whole foods-based multivitamin. These contain the full spectrum of B vitamins that all work together within the body to carry out functions and balance one another, hence the “complex” name this group is given.

Within a vitamin B-complex supplement, you’ll find other important B vitamins — like biotin, thiamine, niacin and riboflavin — that require one another to be present for the best results.

Compared to other vitamins, we don’t need a very large amount of vitamin B12, but we do need to replenish our supplies just about ever day. B vitamins are water-soluble and flushed out of the body somewhat easily, so to maintain levels of the recommended amount within the bloodstream and prevent a vitamin B12 deficiency, we need to eat food sources of B vitamins often.

The NIH reports that the recommended dietary allowance (RDA) for vitamin B12 is:

  • Infants 0–6 months: 0.4 microgram
  • Infants 7–12 months: 0.5 microgram
  • Toddlers 1–3 years: 0.9 microgram
  • Children 4–8 years: 1.2 micrograms
  • Children 9–13 years: 1.8 micrograms
  • Adult men and women over age 14: 2.4 micrograms
  • Women who are pregnant: 2.6 micrograms
  • Women who are breastfeeding: 2.8micrograms

The NIH recommends that adults over 50 years take a daily vitamin B12 supplement or consume foods fortified with vitamin B12. The recommendation is to take between 25–100 micrograms per day, as this amount has been shown to maintain healthy levels of vitamin B12 levels in older people.


The best food sources of vitamin B12 are animal products, like organic meats and wild-caught fish. Cooking with nutritional yeast is another great way to increase your vitamin B12 levels when you aren’t eating meat.

Here are some delicious recipes that contain a good amount of vitamin B12:

Risks and Side Effects

Vitamin B12 absorption can be hindered when someone has a history of alcoholism or heavy smoking. In addition to alcohol and nicotine, long-term antibiotic use can also reduce the ability of the stomach to absorb and use vitamin B12.

For this reason, anyone who has used stomach acid-controlling drugs may want to talk to her or his doctor about needing vitamin B12 supplements.

Potassium supplements can also reduce absorption of vitamin B12 benefits, so if you take large amounts of potassium in supplement form, you should watch out for a possible vitamin B12 deficiency. Potassium from food sources shouldn’t cause a problem, but very high amounts may set someone up for a vitamin B12 deficiency.


  • Vitamin B12 is a water-soluble nutrient in the vitamin B complex that the body needs in small amounts to function properly.
  • Vitamin B12 benefits your energy levels, mood, memory, heart, hair, skin and digestion. It’s also essential for the production of DNA and red blood cells.
  • Vitamin B12 deficiency can lead to a number of health issues, including chronic fatigue, nerve damage, mood disorders, neurodegenerative disorders, heart issues, anemia and neural tube defects in infants.
  • To reverse vitamin B12 deficiency, consume more natural sources of vitamin B12, including beef liver, organic meats and wild-caught salmon. You should also take a probiotic daily and work on the health of your gut by eliminating inflammatory foods.
  • If you are experiencing symptoms of vitamin B12 deficiency because of your dietary choices, age or health condition, consider taking a whole foods-based B complex supplement.

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