Too much or too little B12 might mean higher risk of dying
The origin of vitamin B12 levels and risk of all-cause, cardiovascular and cancer specific mortality: A systematic review and dose-response meta-analysis.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Even moderately high B12 levels (400–600 pmol/L) were linked to a 34% higher risk of death — not just extremely high levels.
Most people assume only very high or very low levels matter — this shows risk increases gradually, even in what many consider ‘normal’ ranges.
Practical Takeaways
Avoid high-dose B12 supplements unless medically diagnosed with deficiency — especially if you’re over 60.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Even moderately high B12 levels (400–600 pmol/L) were linked to a 34% higher risk of death — not just extremely high levels.
Most people assume only very high or very low levels matter — this shows risk increases gradually, even in what many consider ‘normal’ ranges.
Practical Takeaways
Avoid high-dose B12 supplements unless medically diagnosed with deficiency — especially if you’re over 60.
Publication
Journal
Archives of gerontology and geriatrics
Year
2023
Authors
Kefeng Liu, Zhirong Yang, Xiaojing Lu, Bang Zheng, Shanshan Wu, Jian Kang, Shusen Sun, Jie Zhao
Related Content
Claims (6)
If your blood has too little or too much vitamin B12, you might be at higher risk of dying from any cause or from heart disease — the safest range is in the middle, between 190 and 948 pg/mL.
People with very high levels of vitamin B12 in their blood—above 600 pmol/L—might be 50% more likely to die from any cause compared to those with lower levels, which could mean there’s a dangerous upper limit to how much B12 is safe.
People with higher levels of vitamin B12 in their blood seem to have a higher chance of dying from heart problems, but this link isn’t as clear as the link between high vitamin B12 and dying from any cause.
People with higher levels of vitamin B12 in their blood tend to have a slightly higher chance of dying from any cause — especially older adults — so high B12 might just be a sign that something else is wrong in the body.
People with vitamin B12 levels between 400 and 600 units in their blood are 34% more likely to die from any cause than people with lower levels—even though those levels are still considered normal by doctors.