Meat and colorectal cancer: is the risk underestimated?

By Ana Espino | Published on March 4, 2026 | 3 min read


Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide and the second leading cause of cancer-related mortality. In 2020, nearly 1.9 million new cases were reported. Incidence continues to rise, notably due to population aging and shifts in dietary habits.  

Among modifiable factors, consumption of red meat and processed meat remains a subject of persistent scientific debate. The International Agency for Research on Cancer (IARC) classifies processed meat as carcinogenic to humans (Group 1) and red meat as probably carcinogenic (Group 2A). Despite this classification, the exact magnitude of risk and its consistency across tumor sub-sites remain debated.  

Proposed biological mechanisms include the formation of N-nitroso compounds, heterocyclic amines, polycyclic aromatic hydrocarbons, and the roles of heme iron and the microbial metabolite TMAO, which are implicated in oxidative stress and colonic inflammation.  

Given the sometimes heterogeneous results of prospective studies, this 2025 meta-analysis published in GeroScience aimed to precisely quantify the association between red, processed, and total meat consumption and the risk of colorectal, colon, and rectal cancer by integrating all available prospective evidence.  

How much extra risk is on the plate?  

The authors conducted an exhaustive meta-analysis of 60 prospective studies conducted between 1990 and November 2024. Only longitudinal studies reporting adjusted hazard ratios (HRs) were included. Analyses used a random-effects model, with assessment of heterogeneity (I²) and publication bias (Egger’s test).  

For red meat, the pooled analysis (71 cohorts) shows a significant increase in overall colorectal cancer risk—an 18% higher risk among the highest consumers. Associations were observed for colon cancer, rectal cancer, and overall colorectal cancer.  

For processed meat, data from 55 cohorts indicate a 19% increased risk. Publication bias was detected for colon cancer, but not for overall colorectal or rectal cancer. Total meat consumption was also associated with increased risk, with low heterogeneity, strengthening the robustness of the estimate. Subgroup analyses confirmed consistent associations for both colon and rectum, suggesting a broad effect across the colorectal segment. Overall, the increase in risk ranged from 13% to 22% depending on tumor site and meat type.  

Less meat, less risk?  

CRC is a multifactorial disease with a growing global burden and a strong dietary component. Clarifying the role of red and processed meats is central to prevention.  

This meta-analysis sought to consolidate the prospective evidence to estimate the association between meat intake and tumor risk more precisely. The results robustly show that high consumption of red or processed meat is associated with a significant increase in colorectal cancer risk, with relatively consistent estimates across anatomical sub-sites.   

Several limitations should be noted. Dietary intakes were mostly assessed via self-reported questionnaires, which introduces measurement error. Residual confounding related to physical activity, fiber intake, or the gut microbiome may persist. Differences in cooking methods were not uniformly captured.  

Despite these limitations, the findings support international recommendations to limit red meat to 350–500 g per week and to avoid processed meats. Future directions include studying gene–diet interactions, the role of the gut microbiome, and the evaluation of targeted nutritional interventions. At the population level, even modest risk increases translate into substantial public health burden, making dietary modification a key lever for colorectal cancer prevention. 

Read next: Microbiome and colorectal cancer: the invisible enemy?

About the author – Ana Espino
PhD in Immunology, specialized in Virology  
As a scientific writer, Ana is passionate about bridging the gap between research and real-world impact. With expertise in immunology, virology, oncology, and clinical studies, she makes complex science clear and accessible. Her mission: to accelerate knowledge sharing and empower evidence-based decisions through impactful communication.