Vitamin B12 (Cobalamin)

What it isB12 is a cobalt-containing vitamin made by bacteria and obtained almost exclusively from animal foods. It requires intrinsic factor from the stomach for absorption in the ileum.

DoesActs as a cofactor in DNA synthesis, red blood cell production, fatty acid metabolism, and myelin formation around nerves.

GoodHigh-normal B12 supports red cell production, methylation, mood, and cognitive.

BadLow B12 causes megaloblastic anemia, peripheral neuropathy, cognitive impairment that mimics dementia, and elevated homocysteine. Common in vegans, older adults, and those on metformin or acid-suppressing drugs.