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