Common signs of Vitamin B12 deficiency

Vitamin deficiencies can cause all sorts of health problems. If you aren’t eating a balanced diet – or if you follow a special diet that excludes certain food groups – you could have a vitamin deficiency.

Vitamin deficiencies are easy to fix, but it’s important to find out which vitamin you need and how much of it you need to be getting.

Some vitamins, like C and B12, generally won’t cause problems if you take too much.

Too much of other vitamins, like Zinc and Selenium, can cause serious problems ranging from diarrhea to hair loss.

Keep reading to learn more about Vitamin B12, why you need it, and what happens when you aren’t getting enough.

What is Vitamin B12?

Vitamin B12 or “cobalamin” plays a key role in basic body functioning. B12 is sometimes called “the energy vitamin,” which is why you see it advertised in energy drinks and energy shots.

Your body needs B12 for:

  • Proper nerve function
  • Healthy cell metabolism
  • DNA production 
  • Red blood cell production 

In other words, you need B12 to stay energized!

Click here to read a personal story by a woman who struggled with pernicious anemia and B12 deficiency (source: Chicago Tribune).

Common symptoms of B12 deficiency

The symptoms of B12 deficiency are so common that they are usually blamed on something else – like long hours at the office, stress, or lack of sleep. The human body can store B12 for a long time, so it can take up to 4 years before these symptoms start appearing. 

>The most common symptom of a B12 deficiency is fatigue

Without ample amounts of Vitamin B12, your body can’t produce enough red blood cells to distribute oxygen throughout the body. This makes you feel weak, tired, and lightheaded. If you are experiencing unexplained muscle weakness or fatigue despite adequate sleep, talk to your doctor about getting tested for anemia.

Click here to read my article on how to get a good night’s sleep.

>Tingling in the extremities

When your body runs low on B12, the outer layer of your nerve fibers (called “myelin”) starts to break down. This slows down nerve impulses, which can cause a tingling sensation in the hands and feet. 

Click here to learn more about myelin (source: National Multiple Sclerosis Society).

>Pale skin tone

A B12 deficiency can make your skin appear pale or yellowish. This is due to the release of bilirubin pigment that occurs when weak and fragile red blood cells break apart. With less B12, your body produces less red blood cells – and the ones you do have are fragile.

>Changes in appaerance of tongue/ loss of taste

About 50% of people with a B12 deficiency lose the little bumps or “papillae” on their tongues. In this case, the tongue will appear red and smooth.

The loss of papillae can also cause a burning sensation near the back of the tongue and can decrease your sense of taste. In some cases, patients lose weight because they stop enjoying their favorite foods.

>Proprioception problems 

The breakdown of myelin can also affect your “proprioception” – which is a fancy term that refers to a person’s sense of where his or her body is in space. 

This problem manifests as trouble maintaining balance. If you feel wobbly or notice increased clumsiness and stumbling, it’s a good idea to schedule a blood test.

>Confusion and dizziness

The breakdown of myelin in the brain can make people feel confused and forgetful. In just one year, the mental effects of a B12 deficiency can cause symptoms similar to dementia. In the elderly, B12 deficiency has been mistakenly diagnosed as Alzheimer’s.


Feeling down and out goes hand in hand with exhaustion and confusion. While the cause of B12-linked depression is not fully understood, it is believed to be associated with myelin production.

>Vision changes

Over time, an extreme lack of Vitamin B12 can actually damage the blood vessels in your eyes – causing symptoms like double vision, blurry vision, light sensitivity, and in some cases, vision loss. These changes may be permanent. 

Factors that affect B12 absorption 


Some prescription drugs can inhibit the body’s absorption/utilization of B12. Chronic use of the following drugs could be contributing to your B12 deficiency:

  • Colchicine: anti-inflammatory used to treat/prevent gout
  • Chloramphenicol: antibiotic used to treat eye infections, typhoid fever, and other serious bacterial infections
  • Histamine H-2 receptor antagonists (H2-blockers): used to treat ulcers
  • Metformin: used to help regulate blood sugar levels in patients with type 2 diabetes
  • Proton pump inhibitors (PPIs): used to slow acid production to help treat ulcers in the stomach, esophagus, and duodenum

Vitamin C supplements can also interfere with B12 absorption. Make sure to wait at least 2 hours after taking Vitamin C/ascorbic acid supplements before taking B12 supplements.


Any surgery in which part of the stomach has been removed can inhibit the proper absorption of B12

>Bad habits

Drinking alcohol heavily and frequently can get in the way of your body’s absorption of B12.

>Medical Conditions

The following conditions put you at an increased risk of developing a B12 deficiency:

  • Atrophic gastritis
  • Pernicious anemia
  • Crohn’s disease
  • Celiac disease (gluten intolerance)
  • Bacterial growth or parasite in small intestine
  • Graves’ disease
  • Lupus

Up to 15% of Americans don’t get enough Vitamin B12.

Your body needs a steady source of B12 because it doesn’t produce any on its own. You can get B12 through supplements, animal-based, or enriched foods.

Good sources of B12 include:

  • Seafood (salmon, mackerel, sardines, tuna, shrimp)
  • Shellfish (mussels, clams, oysters)
  • Meats (lamb, beef, chicken, turkey)
  • Fortified grains (cereal)
  • Cheese (feta, cottage, Swiss)
  • Milk
  • Eggs

Because the only natural sources of B12 are animal products, individuals who follow vegan and vegetarian diets have a much higher risk of developing a B12 deficiency. If you follow one of these diets, make sure to take supplements or consume enriched foods.

How much B12 do you need? 

  • Young adults (ages 9-13) need about 1.8 mcg per day
  • Adults need about 2.4 mcg per day
  • Pregnant and breastfeeding women need 2.6 mcg and 2.8 mcg per day, respectively

The body’s ability to absorb B12 declines with age. Individuals over the age of 50 are especially advised to take B12 supplements.

The good news about B12

The goods news with B12 is that it is easy to treat once it has been diagnosed. In most cases, it will take just a few weeks of treatment to get rid of your symptoms. Treatment may include diet alterations, supplements, or (in severe cases) injections.

Any nerve damage sustained during the deficiency is likely to be permanent.

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