The Study
Elevated Vitamin B12, Risk of Cancer, and Mortality: A Systematic Review
This study looked at lots of past patient records and found that people with very high B12 levels sometimes had cancer, but it doesn’t prove the high B12 caused the cancer — it might just be that cancer made B12 go up.
Analysis score
Maximum 100 for a systematic review.
Where the score came from
When your blood has way more B12 than normal and no one knows why, it could be a sign of hidden cancer — but not always.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 528 / 100
Quality score
Systematic reviews and meta-analyses of cohort studies. They sit above a single cohort study but below a single randomized trial, because the underlying evidence is still observational.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — if your B12 is very high for no clear reason, doctors should check for cancer, especially lung, liver, or blood cancers.
- 2B12 over 1000 pg/L linked to 1.88 to 5.9 times higher risk of some cancers (lung, pancreas, liver, blood cancers); linked to lower breast cancer risk; no clear link to death risk.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
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.
People with higher levels of vitamin B12 in their blood tend to get breast cancer less often than those with lower levels.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.