Vitamin B12 is a water-soluble vitamin essential for neurological health, red blood cell production, and DNA synthesis. Despite its importance, deficiencies are surprisingly common, especially among older adults and those with specific dietary habits. Let’s explore the causes, symptoms, and solutions for vitamin B12 deficiency.
What Is Vitamin B12?
Vitamin B12 supports:
- Neurological function: It aids in forming the myelin sheath, protecting nerve cells.
- Red blood cell production: Preventing anaemia and fatigue.
- DNA synthesis: Ensuring healthy cellular function.
- Energy metabolism: Helping convert food into energy.
Deficiency can lead to irreversible nerve damage, fatigue, and cognitive decline.
Sources of Vitamin B12
Vitamin B12 is predominantly found in animal-derived foods such as:
- Organ meats (e.g., liver)
- Seafood (e.g., oysters, fish)
- Poultry and eggs
- Dairy products
Plant-based sources like tempeh and miso contain negligible, non-bioavailable forms of B12. Vegans and vegetarians should rely on fortified foods or supplements.
Absorption and Storage
Absorption requires stomach acid and intrinsic factor (IF), a protein produced in the stomach. Age, gastrointestinal conditions, and medications like proton pump inhibitors or metformin can reduce absorption. The liver stores about 3-5 mg of B12, enough to last several years in healthy individuals.
Causes of Vitamin B12 Deficiency
- Pernicious anaemia: An autoimmune condition impairing intrinsic factor production.
- Gastrointestinal disorders: Bariatric surgery, Crohn’s disease, or celiac disease can interfere with absorption.
- Dietary insufficiency: Particularly common in vegans or vegetarians.
Symptoms of Vitamin B12 Deficiency
Neurological Symptoms:
- Tingling or numbness (peripheral neuropathy)
- Memory loss or cognitive decline
- Loss of balance (ataxia)
Physical Symptoms:
- Fatigue and weakness
- Pale or jaundiced skin
- Anaemia, often macrocytic (enlarged red blood cells)
- Glossitis (inflamed tongue)
Untreated deficiency can lead to permanent nerve damage and serious health issues.
Diagnosing Vitamin B12 Deficiency
Testing includes:
- Serum B12 levels: May miss up to 50% of cases.
- Methylmalonic acid (MMA): Elevated levels confirm B12 deficiency.
- Homocysteine: High levels can indicate B12 or folate deficiency.
- Intrinsic factor antibodies: Diagnose pernicious anaemia.
Treating and Preventing Vitamin B12 Deficiency
Supplements:
- Cyanocobalamin or methylcobalamin: 500–2,000 mcg daily.
- Injections: Recommended for severe deficiencies or absorption issues.
Dietary Tips:
- Incorporate B12-rich foods like fish, poultry, and fortified cereals.
- Vegans should consider fortified plant-based milks or nutritional yeast.
Best Practices:
- Take B12 supplements in the morning with other B vitamins.
- Avoid alcohol or antibiotics when supplementing, as these may hinder absorption.
How to Optimise B12 Levels
- Monitor medications: Be mindful of drugs like metformin or proton pump inhibitors, which reduce absorption.
- Regular screenings: Especially important for older adults or vegans.
- Balanced diet: Include B12-rich or fortified foods.
Vitamin B12 is vital for energy, brain health, and overall well-being. Deficiencies are preventable with the right diet, regular screenings, and appropriate supplementation. If you suspect a deficiency, consult your healthcare provider for testing and tailored treatment.