Vitamin B12

Vitamin B12, also known as cobalamin, is a water-soluble vitamin essential for red blood cell formation, neurological function, and DNA synthesis. It plays a crucial role in energy production, brain health, and homocysteine metabolism.

Vitamin B12 RDA (Recommended Dietary Allowance):

• Adults (19+ years): 2.4 µg/day
• Pregnant women: 2.6 µg/day
• Breastfeeding women: 2.8 µg/day
• Children (varies by age): 0.4-1.8 µg/day

ODA (Optimal Daily Allowance):

• 4-25 µg/day (depending on individual needs and health conditions)

Found in:

• Animal products (beef, liver, poultry, fish, eggs, dairy)
• Shellfish (clams, mussels, crab)
• Fortified foods (cereals, plant-based milk, nutritional yeast)
• Supplements (cyanocobalamin, methylcobalamin, adenosylcobalamin, hydroxocobalamin)

Helps with:

• Red blood cell production and prevention of anemia
• Supporting nerve function and myelin sheath formation
• Aiding in DNA synthesis and cell division
• Assisting in energy metabolism and reducing fatigue
• Lowering homocysteine levels, reducing the risk of heart disease
• Supporting brain health, memory, and mood regulation

Insufficient doses:

• Symptoms of deficiency:
  • Fatigue and weakness
  • Neurological symptoms (numbness, tingling, memory loss, mood changes)
  • Megaloblastic anemia
  • Difficulty maintaining balance
  • Glossitis (swollen, inflamed tongue)
• Deficiency is more common in vegetarians, vegans, older adults, and those with malabsorption issues (e.g., pernicious anemia, Crohn’s disease, celiac disease).

Excessive doses:

• No established upper limit (generally well tolerated, as excess is excreted in urine)
• Possible side effects of extremely high doses:
  • Mild digestive issues (nausea, diarrhea)
  • Acne or skin rashes (rare cases)
  • Can interfere with certain lab tests (falsely altering B12-related blood markers)

Types of Vitamin B12:

• Cyanocobalamin: Most stable and commonly used in supplements; must be converted into active forms in the body.
• Methylcobalamin: Bioavailable form that supports neurological health and methylation processes.
• Adenosylcobalamin: Essential for mitochondrial energy production.
• Hydroxocobalamin: Naturally occurring form, often used in B12 injections for better retention.

Interactions (synergy and anti):

• Synergy:
  • Works with folate (vitamin B9) and vitamin B6 for homocysteine metabolism.
  • Aids with iron and vitamin C in red blood cell production.
  • Works with magnesium and other B vitamins for energy metabolism.
• Antagonistic interactions:
  • Excessive alcohol consumption reduces B12 absorption.
  • Certain medications (e.g., metformin, proton pump inhibitors, H2 blockers) decrease vitamin B12 levels.
  • High folic acid intake can mask a B12 deficiency, delaying diagnosis.
  • People that are lacking intrinsic factor need to take a sublingual form of Vitamin B12.