Even though older adults are more likely to be diagnosed with colorectal cancer (CRC), there is a concerning rise in diagnoses among younger adults, making it essential for healthcare providers to educate adult patients of all ages about the lifestyle-related risk factors associated with the disease.
Many are familiar with the modifiable risk factors of obesity, smoking, and alcohol consumption, but the impact of processed meat — a common element of the Western diet — often remains underappreciated.
But the data are clear: Processed meat, defined as meat that has been altered through methods such as salting, curing, fermentation, or smoking to enhance flavor or preservation, has been linked to an increased risk for CRC.
The International Agency for Research on Cancer, part of the World Health Organization, analyzed over 800 global studies and classified processed meats as carcinogenic to humans, whereas red meat was deemed “probably” carcinogenic. Their findings were later published in The Lancet Oncology, confirming that the strongest epidemiologic evidence linked processed meat consumption to CRC.
“While I routinely counsel my patients about lifestyle and dietary risk factors for CRC, including processed meat, I’m not sure how often this is specifically mentioned by physicians in practice,” Peter S. Liang, MD, MPH, an assistant professor and researcher focused on CRC prevention at NYU Langone Health in New York City and an American Gastroenterological Association spokesperson, told Medscape Medical News.
David A. Johnson, MD, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School and Old Dominion University, both in Norfolk, Virginia, concurred.
Many healthcare providers may not fully recognize the risks posed by processed meat in relation to CRC to counsel their patients, Johnson said. “In my experience, there is not a widespread awareness.”
Understanding the Carcinogenic Risks
The excess risk for CRC per gram of intake is higher for processed meat than for red meat. However, the threshold for harmful consumption varies among studies, and many group red and processed meat together in their analyses.
For example, a 2020 prospective analysis of UK Biobank data reported that a 70 g/d higher intake of red and processed meat was associated with a 32% and 40% greater risk for CRC and colon cancer, respectively.
More recently, a 2025 prospective study examined the associations between CRC and 97 dietary factors in 542,778 women. Investigators found that, aside from alcohol, red and processed meat were the only other dietary factors positively associated with CRC, with a 30 g/d intake increasing the risk for CRC by 8%.
Although the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR) recommend limiting red meat consumption to no more than three portions a week, their guidance on processed meat is simpler and more restrictive: Consume very little, if any.
The risk for CRC associated with processed meats is probably due to a naturally occurring element in the meat and carcinogenic compounds that are added or created during its preparation, Johnson said.
Large bodies of evidence support the association between certain compounds in processed meat and cancer, added Ulrike Peters, PhD, MPH, professor and associate director of the Public Health Sciences Division at the Fred Hutchinson Cancer Center in Seattle.
These compounds include:
- Heterocyclic amines: Prevalent in charred and well-done meat, these chemicals are created from the reaction at high temperatures between creatine/creatinine, amino acids, and sugars.
- Nitrates/nitrites: Widely used in the curing of meat (eg, sausages, ham, bacon) to give products their pink coloring and savory flavor, these inorganic compounds bind with amines to produce N-nitrosamines, among the most potent genotoxic carcinogens.
- Polycyclic aromatic hydrocarbons: Generated during high-temperature cooking and smoking, these compounds can induce DNA damage in the colon.
- Heme iron: This type of iron, abundant in red and processed meats, promotes formation of carcinogenic N-nitroso compounds and oxidative damage to intestinal tissue.
Peters said that the compounds may work synergistically to increase the risk for CRC through various mechanisms, including DNA damage, inflammation, and altered gut microbiota.
While it would be useful to study whether the different meat-processing methods — for example, smoking vs salting — affect CRC risk differently, “practically, this is difficult because there’s so much overlap,” Liang noted.
Risk Mitigation
Lifestyle factors probably play a crucial role in the risk for CRC. For example, a study of European migrants to Australia found that those from countries with lower CRC incidences tended to develop a higher risk for CRC the longer they resided in Australia due to the dietary change.
Understanding how to mitigate these risk factors is becoming increasingly important with the rates of early-onset CRC projected to double by 2030 in the United States, a trend that is also being observed globally.
“With early-onset CRC, it’s becoming quite clear that there’s no single risk factor that’s driving this increase,” Liang said. “We need to look at the risk factors that we know cause CRC in older adults and see which have become more common over time.”
The consumption of processed meats is one such factor that’s been implicated, particularly for early-onset CRC. The average global consumption of all types of meat per capita has increased significantly over the past 50 years. A 2022 report estimated that global mean processed meat consumption was 17 g/d, with significantly higher rates in high-income regions. This number is expected to rise, with the global processed meat market projected to grow from $318 billion in 2023 to $429 billion by 2029. Given this, the importance of counseling patients to reduce their meat intake is further underscored.
Another strategy for mitigating the risks around processed meat is specifically identifying those patients who may be most vulnerable.
In 2024, Peters and colleagues published findings from their genome-wide gene-environment interaction analysis comparing a large population with CRC and healthy control individuals. The research identified two novel biomarkers that support the role of red and processed meat with an increased risk for CRC and may explain the higher risk in certain population subgroups. They are working on genetic risk prediction models that will incorporate these genetic markers but must first ensure robust validation through larger studies.
“This approach aligns with precision medicine principles, allowing for more personalized prevention strategies, though we’re not quite there yet in terms of clinical application,” Peters said.
Another knowledge gap that future research efforts could address is how dietary factors influence survival outcomes after a diagnosis of CRC.
“The existing guidelines primarily focus on cancer prevention, with strong evidence linking processed meat consumption to increased CRC risk. However, the impact of dietary choices on survival after CRC diagnosis remains poorly understood,” Peters said. “This distinction between prevention and survival is crucial, as biological mechanisms and optimal dietary interventions may differ significantly between these two contexts.”
Well-designed studies investigating the relationship between dietary patterns and CRC survival outcomes would enable the development of evidence-based nutritional recommendations specifically tailored for CRC survivors, Peters said. In addition, she called for well-designed studies that compare levels of processed meat consumption between cohorts of patients with early-onset CRC and healthy counterparts.
“This would help establish whether there’s a true causal relationship rather than just correlation,” Peters said.
Simple Strategies to Dietary Changes
With a 2024 study finding that greater adherence to WCRF/AICR Cancer Prevention Recommendations, including reducing processed meat consumption, was linked to a 14% reduction in CRC risk, physicians should emphasize the benefits of adopting dietary and lifestyle recommendations to patients.
Johnson advised simple strategies to encourage any needed dietary changes.
“Pay attention to what you eat, proportions, and variation of meal menus. Those are good starter points,” he told Medscape Medical News. “None of these recommendations related to meats should be absolute, but reduction can be the target.”
Liang stressed the importance of repeated, nonjudgmental discussions.
“Research shows that physician recommendation is one of the strongest motivators in preventive health, so even if it doesn’t work the first few times, we have to continue delivering the message that can improve our patients’ health.”
John Watson is a freelance writer in Philadelphia.
