Excellent dietary sources include: Liver and organ meats : Beef liver provides approximately 70 mcg per 100gfar exceeding daily needs Shellfish : Clams, mussels, and crab are exceptionally rich sources Fish : Salmon (5 mcg per 100g), trout, tuna, and mackerel provide substantial amounts Meat and poultry : Beef, lamb, and chicken contain 13 mcg per 100g Dairy products : Milk (0.4 mcg per 100ml), cheese, and yoghurt contribute meaningfully Eggs : One large egg provides approximately 0.6 mcg For vegans and vegetarians , reliable B12 sources are essential as plant foods contain no bioavailable B12 (despite some claims about algae or fermented products)

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PMID: 38797248 10 Vitamin B12 deficiency in the elderly: is it worth screening
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