Vitamin B12
Vitamin B12 is a vitamin the body needs to form red blood cells, keep the nervous system working and turn food into energy.
Vitamin B12 is a vitamin the body needs to form red blood cells, keep the nervous system working and turn food into energy. It is found almost only in animal foods. The body stores B12 in the liver, so the level changes slowly. Retesting shows how it changes over time.
Diet matters most: a vegan or largely plant-based diet without fortified foods or a supplement tends to lower B12. Uptake from the gut becomes less efficient with age, and some medicines, such as acid-reducing medicines and metformin, lower it. Supplements raise the level, often well above what food alone gives.
Foods that help
Fish, shellfish, meat, eggs and dairy. On a plant-based diet, fortified foods such as some plant drinks and breakfast cereals, or a B12 supplement.
Foods to limit
Large amounts of alcohol. High-dose B12 supplements without a clear need make the value hard to read.
Track it through the year
One value is a snapshot. Following it up shows whether what you changed is working.
Related markers
Educational information only — not a diagnosis. Every result is checked against safe limits, and anything critical is escalated for follow-up.
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