# Nutritional guidance on Vitamin B12 and Vitamin D > Developing situation record from CLSTR: https://clstr.news/situations/nutritional-guidance-on-vitamin-b12-and-vitamin-d > Updated: 2026-10-07T13:46:28.000Z. Sources: 6. Developments: 2. Information regarding essential vitamins highlights the biological functions and dietary requirements for Vitamin B12 and Vitamin D. Vitamin B12, or cobalamin, is critical for DNA synthesis, energy metabolism, and nervous system maintenance. While primarily sourced from animal products, deficiencies can arise from absorption issues caused by gastric surgery, infections, or certain medications. The German Nutrition Society (DGE) notes that while standard adult requirements are 4.0 µg, needs increase during pregnancy and breastfeeding. Experts warn that plant-based alternatives like spirulina may not effectively support these needs, and severe deficiency can lead to serious conditions such as paralysis, eye damage, or dementia. Vitamin D is emphasized for its role in bone health and immune function. Although most Vitamin D is produced via sunlight, dietary intake is necessary to maintain reserves, particularly in regions like Germany where winter sunlight is insufficient. The DGE identifies blood levels below 30 nmol/l as a deficiency, which may cause muscle pain and weakened bones. ## Timeline ### 2026-10-07: Nutritional guidance on Vitamin B12 and Vitamin D intake Health experts discuss the dietary requirements for Vitamin B12 and Vitamin D, noting the importance of animal products for B12 and sunlight for Vitamin D to prevent serious health complications. 2 sources. https://clstr.news/cluster/nutritional-guidance-on-vitamin-b12-and-vitamin-d-intake ### 2026-10-04: Vitamin B12: Importance, absorption, and dietary requirements Vitamin B12 is vital for nerve and blood health. Deficiencies can arise from poor absorption despite adequate diet, requiring attention to symptoms like fatigue and specific dietary or medical needs. 4 sources. https://clstr.news/cluster/vitamin-b12-importance-and-dietary-requirements --- Cite as: Nutritional guidance on Vitamin B12 and Vitamin D. CLSTR, https://clstr.news/situations/nutritional-guidance-on-vitamin-b12-and-vitamin-d