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Meat
Red and processed meat consumption and colorectal cancer
Strong evidenceIndependentThe Lancet Oncology, 2015
Sample size
800,000+
participants
Study duration
10+ years
Study type
Meta-analysis of cohort studies
Industry response
The meat processing industry funded multiple counter-studies following the IARC classification. These used shorter durations and smaller samples and should be interpreted with caution.
Plain English summary
Multiple large cohort studies and meta-analyses have established a clear dose-response relationship between processed meat intake and colorectal cancer risk. The IARC classifies processed meat as a Group 1 carcinogen based on this body of evidence.
Key findings
- Consuming 50g of processed meat daily increases colorectal cancer risk by approximately 18%
- The relationship is dose-dependent — greater consumption correlates with greater risk
- Red meat (unprocessed) shows a probable but weaker association (Group 2A)
- Risk remains significant after adjusting for fibre intake, BMI, and other dietary factors