Too much B12? It might mean cancer
Elevated Vitamin B12, Risk of Cancer, and Mortality: A Systematic Review
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Elevated B12 is consistently linked to lower breast cancer risk, while being linked to higher risk of lung, liver, and blood cancers.
Most people assume high nutrient levels are universally protective — this shows the same marker can be protective for one cancer and a red flag for others.
Practical Takeaways
If your B12 level is over 1000 pg/L and there’s no clear reason (like supplements or liver disease), ask your doctor to screen for lung, pancreatic, liver, or blood cancers.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Elevated B12 is consistently linked to lower breast cancer risk, while being linked to higher risk of lung, liver, and blood cancers.
Most people assume high nutrient levels are universally protective — this shows the same marker can be protective for one cancer and a red flag for others.
Practical Takeaways
If your B12 level is over 1000 pg/L and there’s no clear reason (like supplements or liver disease), ask your doctor to screen for lung, pancreatic, liver, or blood cancers.
Publication
Journal
Cancer Investigation
Year
2024
Authors
S. B. Amado-Garzón, Luisana Molina-Pimienta, Andrea Vejarano-Pombo, Mariana Vélez-Bonilla, Jaime Moreno-Chaparro, Adriana Buitrago-Lopez
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 1000 pg/L) seem to have a higher chance of getting certain cancers, like lung, pancreatic, liver, or blood cancers, based on studies that found their risk was nearly twice to almost six times higher.
When someone has cancer, their vitamin B12 levels sometimes go up—but it’s not clear if that’s because the cancer is causing it, or if the high B12 is just a side effect and not actually helping diagnose anything.
Having higher levels of vitamin B12 in your blood doesn't clearly make you live longer or shorter — studies just can't agree on whether it matters at all.
If your vitamin B12 levels are way higher than normal for no clear reason, doctors should check for possible cancer, because it might be a sign something serious is going on inside your body.