The Claim

Serum vitamin B12 concentrations above 600 pmol/L are associated with a 50% higher risk of all-cause mortality compared to serum vitamin B12 concentrations at or below 600 pmol/L, suggesting a potential threshold effect for mortality risk.

Source: The origin of vitamin B12 levels and risk of all-cause, cardiovascular and cancer specific mortality: A systematic review and dose-response meta-analysis.

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
48score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

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.

See the scientific wording

Serum vitamin B12 concentrations above 600 pmol/L are associated with a 50% higher risk of all-cause mortality compared to lower levels, indicating a potential threshold effect for mortality risk.

What the research says

1 study
  1. Study: The origin of vitamin B12 levels and risk of all-cause, cardiovascular and cancer specific mortality: A systematic review and dose-response meta-analysis.

    This study found that people with very high levels of vitamin B12 in their blood (above 600 pmol/L) were 50% more likely to die from any cause than those with lower levels, which is exactly what the claim says.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.