Vitamin B12 (cobalamin) is a crucial water-soluble nutrient vital for healthy nerve and blood cells, DNA production, and energy,<br> obtained from animal products (meat, dairy, eggs) or fortified foods/supplements.<br> Deficiency, common in vegans or older adults, can cause fatigue, nerve issues, anemia, and mood changes, treated with supplements or injections,<br> but generally, excess B12 is excreted, making side effects rare, though high doses are used for specific conditions like deficiency.  <br>
Benefits & Functions<br>
<br>
    Nervous System: Maintains healthy nerve and brain cells, crucial for function and development.<br>
    Red Blood Cells: Essential for forming red blood cells, preventing anemia.<br>
    DNA: Involved in DNA synthesis and cell division.<br>
    Energy: Helps convert food into usable energy. <br>

Sources<br>

    Animal Products: Meat, poultry, fish, eggs, and dairy.<br>
    Fortified Foods: Some cereals, breads, and nutritional yeasts.<br>
    Supplements: Available as oral tablets, sublingual drops, or injections. <br>

Deficiency & Risks<br>

    Who's at Risk:
    Vegans/vegetarians, older adults, people with digestive issues (Crohn's, celiac) or stomach surgery. <br>

Symptoms:
Fatigue, weakness, nerve damage (tingling), cognitive issues, mood changes, and anemia (megaloblastic). <br>

Side Effects & Safety<br>

    Generally Safe:
    As a water-soluble vitamin, the body excretes excess through urine, limiting toxicity. <br>

High Doses:
Sometimes used for cyanide poisoning or high homocysteine, but evidence for other uses (Alzheimer's, fatigue) is limited. <br>

Recommended Intake<br>

    Adults: Around 2.4 micrograms (mcg) daily, with older adults potentially needing more due to absorption issues. <br>