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Could You Have a Vitamin B12 Deficiency?

B12 isn’t just something you’ll hear called out at a bingo hall, it’s also an essential nutrient that plays a vital role in keeping you healthy—from head to toe. 

B12 also called cobalamin, is one vitamin we don’t produce but also can’t do without. 

“B12 is a water-soluble (quickly absorbed, but not stored in the body) vitamin. It is one of eight B vitamins, that assists in many crucial roles, including the function of our nervous system (brain and nerve cells), making red blood cells and supporting our heart health,” said Tiffone Powers-Parker, a registered dietitian and nutritionist with Banner Health in Phoenix, AZ. 

If you don’t get enough B12, however, it can cause several serious health problems. Unfortunately, B12 deficiency is very common but is often overlooked and even misdiagnosed.

By knowing the symptoms and risk factors, you can help ensure you get help before permanent damage occurs. Here’s what to know about vitamin B12 deficiency, a checklist of symptoms and helpful tips and treatment advice.

What causes a B12 deficiency?

A vitamin B12 deficiency can be caused by many factors and conditions, but two common causes are an inability to absorb B12 and a lack of B12 in your diet. 

Impaired absorption

“For B12 to be absorbed in the body, it must first be digested in the stomach by digestive enzymes and stomach acids,” Powers-Parker said. “When B12 reaches the small intestines, it combines with a natural substance called intrinsic factor, which is a protein, to continue the absorption process. When the process doesn’t work right, you may develop pernicious anemia and a B12 deficiency.”

B12 deficiency is very common in older adults. As you age, you're at an increased risk of deficiency due to the natural decline in stomach acid levels.

Other conditions that make it difficult to absorb vitamin B12 may include:

Restrictive diets

B12 can be found naturally in many animal products, such as fish, meat and dairy products. Because of this, long-term vegetarians and vegans who don’t supplement may be at risk.  

How does a vitamin B12 deficiency harm health?

B12 deficiency can cause serious damage to your nervous system and lead to difficulties in cognition, balance, motion and the ability to produce enough red blood cells to supply your body with oxygen.

“Symptoms may include fatigue, neuropathy (pins and needles feeling in your lower body), weakness in legs, pale or yellow skin, mouth sores, memory loss and depression,” Powers-Parker said. “If left untreated, it can lead to nervous system disorders (muscle cramps/weakness), anemia, bowel incontinence and sexual health issues.

The good news is that B12 deficiency is preventable and treatable.

How is a B12 deficiency diagnosed?

If you’re experiencing any of the symptoms listed above and are at risk for a B12 deficiency, it’s important to discuss this with your health care provider and not make a self-diagnosis.

If they suspect a vitamin B12 deficiency, they may request a blood test to look at your B12 levels. 

The serum B12 test is the most widely used, however, results can be false normal or false high. If this is the case, you may require more sensitive testing.

Research shows that measuring B12 in the blood can miss those with deficiencies showing normal B12 blood levels, such as patients with renal failure,” Powers-Parker said. “Ask your provider if they can measure your methylmalonic acid and homocysteine as these are better biomarkers to capture B12 levels. Sometimes the folate inside red blood cells may also be measured.”

How is B12 deficiency treated?

If you’re diagnosed with low B12 levels, treatment will depend on the reason for the vitamin deficiency. Treatment may include changes to your diet, B12 supplements or injections and addressing an underlying health condition that may be causing the deficiency.

“B12 can be found in oral supplementation, such as cyanocobalamin, but other supplements containing B12 include multivitamins/minerals, injections, B-complex, capsules, soft gels and lozenges,” Powers-Parker said. “Talk to your provider or pharmacist to help choose which supplement is best for you.”

How to prevent B12 deficiency

While it may not be possible to prevent all cases of B12 deficiency, there are things you can do to reduce the likelihood of it occurring. 

Eat a healthy diet. B12 can be found naturally in fish, meat, eggs, dairy, fortified breakfast cereals, enriched soy or rice milk and fortified nutritional yeast.

Limit alcohol. Alcohol can damage the lining of the stomach, which may lead to decreased absorption of the vitamin. Limit to two drinks or fewer in a day for men and one drink or fewer in a day for women.

Supplement. If you’re vegan/vegetarian or have a condition that may interfere with the absorption of the vitamin, talk to your provider to see if supplementation is recommended.


Vitamin B12 deficiency is common but may go undiagnosed or be misdiagnosed. It can cause a variety of symptoms that may be confused with other medical conditions. 

If you’re experiencing any of the symptoms or are at risk for a B12 deficiency, talk to your health care provider to undergo appropriate testing and get treatment.

For more articles on vitamins and supplements, check out:

Nutrition Wellness