Vitamin B12 Deficiency: Symptoms, Causes & Treatment

Vitamin B12 deficiency is a medical condition that occurs when the body fails to obtain sufficient B12, an essential nutrient needed for red blood cell formation and nervous system maintenance. This vitamin is critical for DNA synthesis, protein production, and neurological function.

B12 deficiency is common, particularly among vegetarians, vegans, individuals over 60 years old, and those with digestive disorders such as chronic gastritis or Crohn's disease. It is also prevalent in long-term users of diabetes medications (metformin) and proton-pump inhibitors. In Jordan and the Middle East region, higher prevalence rates are observed among elderly populations and those with chronic illnesses.

Symptoms may develop gradually, but early diagnosis and treatment prevent serious complications such as permanent nerve damage (Subacute Combined Degeneration). Treatment is available and effective, including B12 injections or high-dose oral tablets.

Symptoms of vitamin B12 deficiency develop gradually and range from mild to severe depending on the duration and degree of deficiency. Some people may have no symptoms until levels become critically low. Common symptoms include:

• Fatigue and Exhaustion: One of the most common symptoms, resulting from anemia.
• General Weakness and Muscle Fatigue: Difficulty performing daily activities.
• Pale or Yellowish Skin: Due to anemia.
• Shortness of Breath: Especially with minimal physical exertion.
• Numbness and Tingling in Extremities: Particularly in feet and hands, from nerve damage (neuropathy).
• Loss of Balance and Walking Difficulty: From nerve and balance impairment.
• Difficulty Concentrating and Memory Problems: Cognitive issues and brain fog.
• Depression and Anxiety: Mood changes and psychological symptoms.
• Diarrhea or Constipation: Gastrointestinal issues.
• Loss of Appetite: May lead to weight loss.
• Sore and Swollen Tongue (Glossitis): Tongue may appear red and enlarged.
• Headaches and Dizziness: Especially when standing up quickly.

• Poor Diet: Insufficient intake of B12-rich foods such as meat, fish, dairy, and eggs, common among vegetarians and vegans.
• Gastrointestinal Disorders: Atrophic gastritis reduces secretion of intrinsic factor, essential for B12 absorption.
• Surgical Removal of Stomach or Intestine: Bariatric surgery or bowel resection decreases B12 absorption.
• Medications: Metformin and proton-pump inhibitors (used long-term for acid reflux) reduce B12 absorption.
• Pernicious Anemia: Autoimmune disease that destroys cells producing intrinsic factor, preventing B12 absorption.
• Chronic Liver and Kidney Disease: Impair B12 storage and metabolism.
• Intestinal Parasites: Such as fish tapeworm, which competes for B12 absorption.
• Hyperthyroidism and Recurrent Infections: Increase B12 consumption rate.

• Age over 60: Older adults are at higher risk because stomach acid production decreases with age.
• Vegetarians and Vegans: B12 naturally occurs only in animal products.
• Long-term Metformin Use: A common medication for type 2 diabetes.
• Chronic Gastrointestinal Disorders: Crohn's disease, ulcerative colitis, celiac disease.
• Previous Stomach or Bowel Surgery: Including weight-loss surgery or cancer treatment.
• Pernicious Anemia or Family History: Genetic and autoimmune predisposition.
• Chronic Use of Acid-Suppressing Medications.
• HIV/AIDS and Chronic Infections: Increase nutrient demands.
• Alcohol Addiction: Reduces nutrition and nutrient absorption.
• Pregnancy and Breastfeeding: Increase B12 requirements.

Diagnosis is based on symptom assessment, physical examination, and laboratory tests. Confirmation is important before starting treatment, as symptoms may mimic other conditions.

• Medical History and Physical Examination: Physician inquires about symptoms, diet, medications, and previous surgeries. Skin, extremities, and neurological reflexes are examined.
• Complete Blood Count (CBC): Detects anemia with large red blood cells (macrocytic anemia), where mean corpuscular volume (MCV) exceeds 100 femtoliters (normal 80-100).
• Serum B12 Level: Normal range is 200-900 picograms/mL. Levels below 200 indicate deficiency, though symptoms may occur at 200-400.
• Methylmalonic Acid and Homocysteine Levels: More sensitive markers for B12 deficiency, even when B12 levels are borderline.
• Intrinsic Factor and Antibody Tests: Assess for pernicious anemia.
• Schilling Test: Determines if deficiency is due to malnutrition or malabsorption.
• Liver and Kidney Function Tests: Rule out chronic diseases contributing to deficiency.

Medications

• Vitamin B12 Injections (Intramuscular): First-line and most effective treatment, especially for severe cases or malabsorption. Usually given as 1,000 micrograms monthly or every 2 months. Typically 6 weekly injections initially, then maintenance doses.
• High-Dose Oral B12 Tablets: Used for mild to moderate deficiency or maintenance after injections. Usually 2,000 micrograms daily or 3 times weekly.
• Nasal B12 Spray: Alternative for those unable to tolerate injections.
• Multivitamins Containing B12: For prevention and maintenance, but insufficient for treating severe deficiency.

Procedures/Surgery

• No direct surgical interventions for B12 deficiency itself, but treating underlying causes may require procedures. For example, severe GERD may need antireflux surgery; gastric cancer may require gastrectomy.

Lifestyle Changes

• Improve Diet: Consume B12-rich foods such as beef, fish, chicken, liver, eggs, milk, yogurt, and cheese. Vegetarians should eat B12-fortified foods like soy milk and cereals.
• Reduce Alcohol: Alcohol abuse reduces B12 absorption and increases nerve damage.
• Adhere to Treatment: Take injections or tablets regularly as prescribed. Deficiency may return if treatment stops.
• Regular Monitoring: B12 levels should be rechecked 1-3 months after starting treatment to ensure normalization.
• Manage Chronic Diseases: Diabetes and GERD management contribute to preventing B12 deficiency.
• Discontinue Harmful Medications if Possible: If metformin or acid suppressors are the cause, discuss with physician about dose reduction or cessation (under medical supervision).

• Permanent Nerve Damage (Subacute Combined Degeneration): If deficiency remains untreated long-term, permanent spinal cord and peripheral nerve damage may occur, leading to disability even after treatment.
• Dementia and Memory Disorders: Chronic deficiency may cause permanent cognitive impairment, especially in elderly patients.
• Severe Anemia: May lead to heart failure, severe shortness of breath, and rarely, death.
• Infertility and Male Infertility: B12 is essential for sperm production and fertility.
• Increased Risk of Falls and Fractures: Balance impairment and muscle weakness increase fall risk, particularly in elderly.
• Cardiovascular Complications: Elevated homocysteine levels (from B12 deficiency) are associated with heart disease and stroke.
• Severe Depression and Psychiatric Disorders: May lead to suicidal ideation in severe cases.

• Eat a Balanced Diet Rich in B12: Red meat, poultry, fish, eggs, milk, and cheese provide adequate B12. Include at least one serving daily.
• For Vegetarians and Vegans: Choose B12-fortified foods such as soy milk, almond milk, cereals, and nutritional yeast, or take daily B12 supplements (1,000 micrograms).
• Caution with Chronic Medications: If using metformin or acid suppressors long-term, ask your doctor to check B12 levels annually.
• Reduce Alcohol Consumption: Alcohol impairs B12 and nutrient absorption.
• Manage Gastrointestinal Disorders: If you have chronic gastritis or Crohn's disease, follow treatment consistently and ask about periodic B12 screening.
• Routine Screening for Older Adults: People over 50 should consume natural or fortified B12 sources, or take supplements after consulting a physician.
• Don't Delay Treatment: If symptoms like fatigue and tingling appear, see a doctor promptly and don't delay diagnosis.
• Follow-up After Surgery: If you had gastrointestinal surgery, ask your physician about B12 intake and supplementation.