Evidence review
Low B12 Cardiovascular Risk Review: What the Studies Actually Show
This Low B12 Cardiovascular Risk Review examines the association between low vitamin B12, homocysteine and cardiovascular disease risk without treating a lab result as a diagnosis.
Association is not causation
Observational studies can identify patterns between low B12 and cardiovascular disease, but they cannot prove that B12 deficiency causes cardiovascular events. Kidney function, inflammation, age, diet, medication use and existing disease can influence both B12 status and risk.
The homocysteine pathway
Vitamin B12 helps recycle homocysteine, an amino acid involved in one-carbon metabolism. When B12 is low, methylmalonic acid and homocysteine may rise. That mechanism is biologically plausible, but lowering a biomarker does not always lower cardiovascular disease events.
What to take from the research
Correcting confirmed B12 deficiency is sensible for blood, nerve and metabolic health. It should complement—not replace—proven cardiovascular disease prevention such as blood pressure control, lipid management, smoking cessation, movement and a balanced diet.