Because B12 is essential for nerve health, deficiency can cause neuropathy—resulting in tingling sensations, numbness, or burning sensations.

7. Digestive Problems

Some people experience nausea, constipation, poor appetite, or other digestive discomforts when B12 is insufficient.

8. Nervousness or Irritability

Low B12 can heighten stress responses, making someone more easily agitated or anxious.

9. Heart-Related Issues

Deficiency may increase homocysteine levels, which can strain the cardiovascular system and elevate the risk of heart problems.

What Causes Vitamin B12 Deficiency?

There are several different reasons why someone may develop low B12 levels. Some are dietary, while others are related to absorption issues in the digestive tract:

• Inadequate Diet

Since B12 is naturally found in animal products, individuals following vegan or strict vegetarian diets are more likely to be deficient unless they consume fortified foods or supplements.

• Gastritis or Low Stomach Acid

The body needs stomach acid to absorb B12. Conditions that reduce acid production—such as chronic gastritis—can interfere with absorption.

• Pernicious Anemia

This autoimmune condition prevents the stomach from producing intrinsic factor, a protein essential for absorbing B12.

• Digestive Disorders

Conditions like Crohn’s disease and celiac disease damage the intestinal lining, limiting nutrient absorption.

• Gastrointestinal Surgeries

Procedures such as gastric bypass reduce the part of the stomach or intestine responsible for absorbing B12.

• Excessive Alcohol Consumption

Chronic alcohol use can irritate the stomach lining and reduce nutrient absorption.

• Rare Genetic Disorders

Some people are born with genetic conditions—such as transcobalamin II deficiency—that interfere with B12 transport in the body.

Top 9 Foods Rich in Vitamin B12

• Incorporating B12-rich foods can help prevent deficiency and support overall health:
• Liver – One of the richest natural sources of both B12 and iron.
• Shellfish – Oysters, cockles, and other shellfish provide high levels of the vitamin.
• Salmon – Nutritious and supportive of heart and brain function.
• Tuna – Another excellent, protein-rich source.
• Ground Beef – Provides both B12 and essential minerals.
• Milk – A simple daily option with steady B12 content.
• Yogurt – Good for digestion and naturally contains B12.
• Eggs – Easy to add to meals and nutrient-dense.
• Fortified Cereals – A convenient option for those avoiding animal products.
  

  Bottom Line

  Vitamin B12 is a vital nutrient that supports energy production, nerve function, and overall well-being. If you recognize any symptoms of deficiency—or fall into a high-risk group—it’s important to consult a healthcare professional. Pairing medical advice with a diet rich in B12 foods can help protect your health and prevent complications over time.