Health · Medical Research · 2 hrs ago
Low B12 is linked to heart disease, but supplements show mixed results
A review examined links between low vitamin B12 and cardiovascular disease using laboratory research, population studies and clinical trials.
Vitamin B12 is found naturally in animal foods, and the body needs it to process homocysteine, a substance that can build up when B12 is low.
Researchers describe possible effects on blood vessels and heart rhythm, but the clinical importance of these effects remains uncertain.
Observational studies have linked low B12 with problems including stroke and heart failure, but those links do not prove that low B12 caused them.
Trials found that B-vitamin combinations could lower homocysteine, yet supplements have not consistently prevented major cardiovascular events such as heart attacks or cardiovascular deaths.
The clearest possible benefit is for combined B-vitamin treatment to prevent stroke, especially in populations without mandatory folic acid fortification.
Low vitamin B12 levels are associated with cardiovascular disease, but supplements have not consistently prevented major cardiovascular events.
A narrative review in the Nutrition Journal examined possible effects of B12 deficiency on blood vessels and evidence from supplementation trials.
The review describes oxidative stress, impaired blood-vessel function and elevated homocysteine as possible pathways linking deficiency to vascular harm.
The strongest evidence of possible benefit concerns combined B-vitamin therapy for stroke prevention, particularly where folic acid is not mandatorily added to food.
The clinical significance of the proposed vascular effects remains uncertain.
- Who
- Researchers who reviewed laboratory studies, population studies and clinical trials.
- What
- A review found low B12 levels are associated with cardiovascular disease, while supplementation has not consistently prevented major cardiovascular events.
- When
- The review was published on October 28, 2026.
- Where
- The review was published in the Nutrition Journal.
- Why
- Researchers examined how B12 deficiency might affect blood vessels and whether supplements could protect cardiovascular health.
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- Publication date
- October 28, 2026
- Journal
- Nutrition Journal
- Homocysteine reduction in NORVIT
- About 27 percent
- Potential benefit
- Combined B-vitamin therapy may help prevent stroke, especially where folic acid fortification is not mandatory