Does red and processed meat really increase your risk of colorectal cancer?

Multiple large meta-analyses of prospective research consistently show that people with a high consumption of red meat have a 15 to 22 percent higher risk of colorectal cancer compared with people who eat little red meat. This applies to colon cancer and rectal cancer separately. These are associations established across large groups of people over long periods of time, not a proven causal relationship in the strict sense, but the pattern is remarkably consistent across studies.

For processed meat, such as sausage, ham and bacon, the association is at least as strong. Meta-analyses show a 13 to 21 percent higher risk, and the relationship appears to be dose-dependent: each additional 50 grams of processed meat per day is associated with approximately 18 percent more risk. There appears to be a kind of ceiling around 140 grams of combined red and processed meat per day, beyond which the risk does not rise further. This makes processed meat in particular a concrete point of focus for prevention.

Clinical review articles confirm that red and processed meat are recognised as established risk factors for colorectal cancer and colorectal polyps, comparable in weight to obesity and physical inactivity. In that respect they stand alongside age, sex and heredity as the factors that doctors and researchers consider when estimating risk.

Beyond colorectal cancer, an elevated risk has also been found for other types of cancer: breast cancer (approximately 9% higher with high red meat consumption), lung cancer (26%), uterine cancer (25%) and hepatocellular cancer (22%). The evidence for these is less robust than for colorectal cancer. Notably, a large French cohort study found no association for prostate cancer, which shows that red meat does not carry the same risk for every cancer type.

Epidemiological research estimates that approximately half of the colorectal cancer risk can be influenced through lifestyle factors, including diet. Limiting red and processed meat is recommended as a preventive measure in multiple studies. Direct evidence from intervention studies, in which people are followed after a deliberate dietary change, is largely absent. Nevertheless, the overall picture points strongly toward eating less processed meat being a meaningful and concrete step, especially given the consistency and dose-dependence of the findings.