Widespread Vitamin B12 Deficiency

Vitamin B12 deficiency - Dr. Axe

It’s estimated that up to 25 percent of all adults are at least marginally deficient in vitamin B12 (also called cobalamin). Some experts believe this number may actually be a lot higher, since it’s suspected that there are many cases of undetected vitamin B12 deficiency.

This means there are millions of people likely struggling with B12 deficiency who don’t even know it, especially the elderly and people who avoid eating animal products (vegans and vegetarians).

Commonly known as the “energy vitamin,” vitamin B12 may help improve your energy and assist you in overcoming exhaustion. It does this by supporting thyroid function and cellular methylation. It’s also involved in synthesis of DNA, fatty acids,and myelin that protect cells.

Since it’s a vitamin that’s essential for human life, people deficient in it can suffer from serious health issues if the problem is not addressed.

Why You Need Vitamin B12

Vitamin B12 has the most complex and largest chemical structure of all vitamins. Unlike other vitamins, it contains cobalt (a metal) and is commonly referred to as “cobalamin,” a catchall term for all of the various compounds that contain vitamin B12 properties.

A few of the more important roles that vitamin B12 plays in the body include:

  • Red blood cell formation
  • Memory recall
  • Cellular energy
  • Nutrient absorption
  • Adrenal gland support
  • Nerve and brain regeneration
  • DNA synthesis
  • Female and male reproductive health

Vitamin B12 Deficiency Symptoms

What can happen if you have a vitamin B12 deficiency? Symptoms of vitamin B12 deficiency can include:

  • Low energy or sometimes chronic fatigue
  • Lack of focus and other cognitive difficulties
  • Tension in muscles
  • Poor memory
  • Emotional mood swings
  • Lack of motivation
  • Female infertility
  • Male low testosterone
  • Digestive issues (like leaky gut or IBD)
  • Hypothyroidism
  • Fatigue, even after getting a good night’s sleep

Vitamin B12 Deficiency Anemia:

There are two different types of anemias linked to vitamin B12 deficiency. One type if known as megaloblastic anemia, in which red blood cells don’t develop normally and are abnormally large.

Another rare type is pernicious anemia (or “vitamin B12 anemia”), which is the official term describing vitamin B12 malabsorption, in which a person cannot properly absorb vitamin B12. Pernicious anemia can be caused by an autoimmune disorder that damages the stomach lining.

Typically people do not start to experience symptoms until after they are 30 years old, and the average age of diagnosis is 60. Pernicious anemia is quite complicated and very much involved with several organ systems in the body.

  • Damage done to the stomach lining triggers a dangerous cascade of events that reduces stomach acid and prevents the body from properly breaking down foods.
  • As the condition continues, a hormone called “intrinsic factor” is greatly reduced, which is necessary to absorb vitamin B12.
  • People suffering from this condition require a significant amount of supplementation.

The key to treating pernicious anemia is to reduce chronic inflammation in the body.

According to the Linus Pauling Institute at Oregon State University, pernicious anemia and B12 malabsorption are associated with a chronic inflammatory disease in the stomach, referred to as atrophic gastritis (low stomach acid). This condition is associated with auto-antibodies that target stomach cells and bacterial infection. The ensuing inflammation can lead to peptic ulcers, SIBO and bacterial overgrowth.

Keep in mind that anemia can also be caused by lack of iron and folate/folic acid, so consuming and absorbing all of these nutrients is crucial.

Causes/Risk Factors

What is the main cause of vitamin B12 deficiency?

The two most common ways you become vitamin B12 deficient are through a lack of vitamin B12 in your diet or through your inability to absorb it from the food you eat.

What puts you at an increased risk for developing vitamin B12 deficiency? 

You’re more likely to develop a deficiency in vitamin B12 if:

  • You have had H. pylori bacterial infection or stomach ulcer
  • You are over 50
  • You are a vegan or vegetarian
  • You’ve had weight loss/bariatric surgery, since this surgery interferes with the release of B12 during digestion
  • You have inflammatory bowel disease, leaky gut or other serious digestive disease
  • You have acid reflux
  • You’re a pregnant woman (who has increased needs for many nutrients)
  • You take one of the following types of medications: antibiotics, anti-gout, blood pressure, birth control pills, cholesterol-lowering drugs, diabetes medications and antipsychotic drugs.

As you can see, many people are at risk, but it’s believed that by far the largest cause of vitamin B12 deficiency is malabsorption.

Like most health issues, it all starts in the gut. The American Journal of Clinical Nutrition explains that “malabsorption of the vitamins from food” is the primary cause of vitamin B12 deficiency. This malabsorption could likely be caused by a condition known as leaky gut.

One important factor to keep in mind is that as people age their gastric mucosa naturally shrinks. This makes B12 absorption issues more common and difficult to reverse.

This is one of the main reasons that older adults should either supplement or greatly increase their intake of vitamin B12-rich foods.

Complications/Related Conditions

Is B12 deficiency serious or dangerous?

Being deficient in in this crucial vitamin puts people at an increased risk of developing a number of symptoms and several diseases. What are the long-term effects of B12 deficiency? Examples include:

What are the neurological symptoms of B12 deficiency?

A major risk of remaining deficient in B12 is experiencing cognitive difficulties. In fact, as it relates to neurological function, few vitamins are as critical as B12.

Being a co-factor of methionine synthase, it is heavily involved in different regulatory mechanisms and brain development. Studies show that B12 deficiency later in life actually leads to brain atrophy (shrinkage) and higher risk for problems, including dementia and Alzheimer’s disease (regardless if people are “healthy” or not).

Elderly people who simply lack B12 are at risk of developing what German researchers refer to as “irreversible structural brain damage.”

Other neurological symptoms tied to this deficiency can include memory loss, difficulty thinking and reasoning, and higher risk for MS.

Vitamin B12 also benefits your mood, energy level, memory and entire central nervous system, so it’s also an essential vitamin for addressing symptoms like numbness or tingling. It’s also needed for conditions such as adrenal fatigue, mood disorders like depression, and negative effects of chronic stress or feeling run down.

How long does it take to recover from vitamin B12 deficiency?

It depends how severely someone is deficient and what type of dietary changes plus supplements that person uses to reverse the condition. In most cases, it takes at least several weeks and possibly several months.

How is vitamin B12 deficiency diagnosed?

To diagnose B12 deficiency, doctors typically run several tests, especially a blood test (plasma/serum). Results from a vitamin B12 deficiency test can indicate if levels are lower than normal.

Levels lower than < 148 pmol/L indicate true deficiency, while levels ranging from 148–221 pmol/L get a “marginal status.”

Screening/testing for vitamin B12 deficiency is recommended in patients with one or more risk factors, such as:

  • gastric or small intestine resections
  • inflammatory bowel disease
  • use of metformin for more than four months
  • use of proton pump inhibitors or histamine H2 blockers for more than 12 months
  • vegans or strict vegetarians
  • adults older than 75 years

Related: What You Need to Know About the Most Common Nutrient Deficiencies in Women


How much vitamin B12 do you need to prevent vitamin B12 deficiency?

According to the most recent National Institutes of Health reports, the amount of vitamin B12 that people should consume depends primarily on their age. The average recommended daily amount of vitamin B12 for adults is 2.4 micrograms.

However, according to many health experts, this amount may be too low for some people, especially those who have digestive issues and/or are over 50 years of age.

How to Naturally Increase Your Vitamin B12 Intake:

How can you raise your B12 levels fast? If you think you might be deficient in vitamin B12, the best way to address the issue is to start consuming foods that are high in vitamin B12.

Plants and animals do not produce vitamin B12 — bacteria actually do! This is why consuming probiotic-rich foods and those grown in the ground that contain soil-based organisms is essential to your health.

Since most animals are able to concentrate and store significant levels of vitamin B12 in the bacteria that they house in their flesh, eating grass-fed meat is one of the best sources that you can get. Seafood also concentrates vitamin B12 in large quantities.

Top 10 Vitamin B12 Foods:

The top vitamin B12 rich foods are:

  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)

When cooking these foods, please use caution. Even though it’s a very stable molecule, vitamin B12 can still be destroyed when heated to high temperatures. Cooking your meat to medium-rare increases the overall levels of vitamin B12.

Best Vitamin B12 Supplements:

What can you take for B12 deficiency? Since your gut is actually able to produce some B12 on its own, enhancing the health of your digestive tract is crucial when it comes to maintaining proper vitamin levels.

This is why, in addition to eating a diet rich in soil-based organisms and taking a B12 supplement, you want to take a probiotic supplement to make sure you get enough vitamin B12.

When buying a vitamin B12 supplement, look for the form of methylcobalamin or hydroxycobalamin, rather than cyanocobalamin, because these forms are more natural and typically better absorbed by the body.

For most people, to increase your intake of vitamin B12 you want to take:

  1. Natural vitamin B12 capsules — 200 micrograms twice daily, sublingual or spray
  2. Live probiotic supplement — 25 billion cultures twice daily

Additionally, one other natural supplement that is high in vitamin B12 you may consider taking is desiccated liver tablets, made from dried liver that is high in available nutrients, including B12, iron and others.

Vitamin B12 Shots/Injections:

Vitamin B12 shots or injections are now a common form of vitamin b12 deficiency treatment that people seek out — for example, if they’re recovering from severe deficiency, some illnesses or surgery.

For those with severe deficiencies due to inflammatory bowel disease, this may be necessary for a time, but to truly address the cause of vitamin B12 deficiency, it’s important to repair the digestive tract.

One natural alternative to vitamin B12 injections is vitamin B12 spray. In this form, the vitamin B12 doesn’t have to go through your digestive tract and can be absorbed through the skin.


  • Vitamin B12 is an essential nutrient that plays a role in red blood cell formation, memory, cellular energy, nutrient absorption and other processes.
  • Deficiency in this nutrient can cause many problems, including cognitive issues, low energy, moodiness, weakness, and thyroid and adrenal problems.
  • Malabsorption is the biggest cause of deficiency. This might be due to autoimmune issues, digestive disorders, older age or surgery, among other causes.
  • To improve vitamin B12 status, consume more from your diet (such as from meat, fish, eggs, liver and cheese), and consider supplementing, especially if you don’t eat animal products.
  • You can also take methylcobalamin or hydroxycobalamin supplements daily or even try B12 injections if you know your blood level is low.

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