Is being low in B12 common?

December 29, 2025 •

3 min read

According to a National Health and Nutrition Examination Survey (NHANES) analysis, approximately 3.6% of U.S. adults are B12 deficient, with an additional 12.5% having marginal levels. The question, 'is being low in B12 common?' has a nuanced answer, as its prevalence varies significantly across different age groups and populations.

Quick Summary

Vitamin B12 insufficiency is quite common, particularly among older adults and individuals with malabsorption issues or specific dietary restrictions, like veganism. Recognizing the subtle symptoms is key to understanding your risk.

Key Points

Prevalence varies: While severe B12 deficiency is not widespread, marginal insufficiency is quite common, affecting significant portions of the elderly and vegan populations.
Malabsorption is a primary cause: For most people, low B12 is caused by absorption issues (e.g., pernicious anemia, gastric surgery) rather than a simple lack of intake.
Symptoms are subtle: Early signs of B12 deficiency can be vague, including fatigue, tingling, and mood changes, which can delay diagnosis.
Diet and lifestyle are key factors: Vegans must supplement or rely on fortified foods, while older adults may need supplements due to age-related malabsorption.
Treatment depends on the cause: Treatment options range from oral supplements for dietary issues to injections for severe malabsorption, with many requiring lifelong management.
Early diagnosis is crucial: Prompt identification and treatment are necessary to prevent the progression of symptoms, particularly neurological issues, which can sometimes become irreversible.

Is Being Low in B12 Common?

While severe vitamin B12 deficiency (clinically low levels) is not a pandemic, vitamin B12 insufficiency (marginal levels) is relatively common, especially in certain populations. The causes for a deficiency are often related to absorption problems rather than just dietary intake, making being low in B12 a widespread issue affecting various demographics. The body's ability to store B12 for several years means that symptoms can appear gradually.

Prevalence of Low B12

The prevalence of B12 deficiency varies significantly based on definition and population. A 2007–2018 NHANES analysis showed 3.6% of U.S. adults aged 19 and older were B12 deficient, with 3.7% in those 60 and older. Marginal levels (<300 pg/mL) affect about 12.5% of adults, including older adults. Other studies suggest 10% to 30% of those over 65 have functional B12 deficiency. Global rates can be higher in developing regions.

Primary Causes of Low B12

Most cases of low B12 in developed countries are due to malabsorption rather than low dietary intake, except for vegans.

Common causes include:

Dietary insufficiency: Especially for vegans who don't consume fortified foods or supplements.
Pernicious anemia: An autoimmune condition preventing intrinsic factor production, needed for B12 absorption.
Atrophic gastritis: Stomach inflammation reducing acid needed to release B12 from food.
Digestive diseases: Conditions like Crohn's and celiac disease damaging the small intestine.
Gastric surgery: Procedures affecting stomach or intestine function.
Certain medications: Long-term use of drugs like metformin, proton pump inhibitors, and H2 blockers.
Older age: Reduced stomach acid and higher rates of atrophic gastritis.

How to Identify a Deficiency

Symptoms are often gradual and non-specific.

Common symptoms include:

Fatigue and weakness
Pale or jaundiced skin
Sore tongue and mouth ulcers
Neurological issues like numbness, tingling, vision problems, and difficulty with balance
Psychological symptoms like depression and irritability

Diagnosis and Treatment

Diagnosis involves blood tests for B12 levels, and sometimes MMA or homocysteine.

Comparison of B12 Deficiency Causes & Treatments


Cause	Mechanism	Diagnosis	Treatment
Dietary Insufficiency	Low intake of animal products or fortified foods.	Blood tests for B12, MMA, and homocysteine.	Oral supplements, dietary changes, or fortified foods.
Malabsorption (Pernicious Anemia)	Autoimmune attack on intrinsic factor-producing stomach cells.	Blood tests for B12, MMA, intrinsic factor antibodies.	Intramuscular injections are the standard treatment; high-dose oral supplements may be used for maintenance.
Malabsorption (Gastric Surgery)	Removal or bypass of parts of the stomach or small intestine.	Blood tests for B12, MMA. Lifelong monitoring.	Intramuscular injections are often required for life.
Malabsorption (Medications)	Drug side effects reducing B12 absorption (e.g., Metformin, PPIs).	Blood tests for B12, MMA. History of medication use.	Oral supplements, potentially for as long as medication is taken.

Treatment depends on the cause. Oral supplements work for many, but severe malabsorption often requires injections. Always consult a healthcare provider for the best plan.

Managing Your B12 Levels

Preventive measures are key for those at risk. Dietary sources are mainly animal products, so vegans need fortified foods or supplements. Those with malabsorption typically require supplementation. The NIH Office of Dietary Supplements provides comprehensive information [For more information, visit the NIH Office of Dietary Supplements website.].

Conclusion: A Widespread and Often Overlooked Issue

Being low in B12, particularly marginal insufficiency, is common in specific populations like older adults and vegans. The subtle symptoms can lead to delayed diagnosis and potential long-term neurological complications. Understanding risks, recognizing symptoms, and seeking professional diagnosis and treatment are vital for managing low B12 and maintaining long-term health.

Frequently Asked Questions

Yes, being low in B12 is notably common among older adults. Studies indicate that up to 20% of those aged 60 and over may have a deficiency due to decreased stomach acid and malabsorption, which are frequent issues with aging.

Early signs can be subtle and include fatigue, persistent weakness, a pale complexion, and a sore or red tongue. As the deficiency progresses, neurological symptoms like tingling or numbness in the extremities can develop.

No, natural food sources of B12 are primarily animal products. Vegans must consume fortified foods, such as certain cereals, nutritional yeast, and plant milks, or take regular B12 supplements to prevent a deficiency.

Diagnosis is typically done through a blood test to measure serum B12 levels. Healthcare providers may also test for elevated levels of methylmalonic acid (MMA) or homocysteine, which are more sensitive indicators of a deficiency.

Not necessarily. While injections are essential for people with severe malabsorption issues like pernicious anemia, high-dose oral tablets can be equally effective for many others, including those with dietary insufficiency or age-related malabsorption.

Long-term use of several common medications can interfere with B12 absorption. These include metformin (for diabetes) and stomach acid-reducing drugs like proton pump inhibitors (PPIs) and H2 blockers.

The most common cause of clinically evident B12 deficiency is pernicious anemia. This autoimmune disorder leads to a lack of intrinsic factor, a protein needed to absorb B12 from the digestive tract.