What should I know about vitamin b 12 ernahrung?

Vitamin B12 is an essential nutrient found almost exclusively in animal products (meat, fish, eggs, dairy). It is critical for red blood cell formation, nerve function, and DNA synthesis. Deficiency can cause fatigue, neurological issues, and anemia. At-risk groups include vegans, older adults (due to reduced stomach acid), and individuals with gastrointestinal disorders (e.g., Crohn's disease, atrophic gastritis). Certain genetic variants (e.g., FUT2 rs602662) may slightly reduce absorption, but the effect is small. Supplementation is recommended for risk groups; oral doses are usually effective. B12 toxicity is extremely rare because excess is excreted. A blood test measuring holotranscobalamin is more reliable than total serum B12. Evidence is based on clinical practice and dietary guidelines. Note: DNA tests alone are not diagnostic; consult a healthcare provider for personalized advice.