Early-Onset Colorectal Cancer and Diet: Which Foods Pose a Risk?

Colorectal cancer has become a rapidly growing health concern, particularly among younger people. This has opened new areas of research beyond conventional risk factors. A study by Jayakrishnan and colleagues, published on 17 July 2024 in npj Precision Oncology, suggested that diet-derived molecules associated with red and processed meats, in early-onset colorectal cancer, may act as the main drivers of risk.

The Rationale for the Study

Despite successful colorectal cancer surveillance and screening, younger patients may need different approaches. Applying screening models used for people over 50 to young adults is impractical: routinely recommending colonoscopy to younger patients is neither feasible nor necessarily needed. A simpler, more practical approach would be a biomarker test to determine individual colorectal cancer risk, identify those at highest risk, and offer appropriate screening. Investigating this approach was the study’s main motivation.

In an earlier study, researchers identified metabolite differences between early- and average-onset colorectal cancer. Other research had also found differences in the gut microbiome between younger and older patients. These findings provide many possible avenues for investigating early-onset colorectal cancer, but understanding how individual factors affect risk becomes harder when additional factors are involved.

Study Methods and Results

In this study, researchers examined large-scale data obtained from patients receiving treatment for early- or average-onset colorectal cancer, including metabolite and microbiome datasets . They analyzed these datasets and, to combine existing study data and identify the most important factors for future investigation, developed an artificial intelligence algorithm . The analysis found that diet-related metabolites explained a substantial proportion of differences between early- and later-onset patients.

Diet Rather Than the Microbiome

Study co-leader Dr. Naseer Sangwan of Cleveland Clinic notes the growing interest in the gut microbiome’s role among factors contributing to colorectal cancer risk. However, he emphasizes that these data clearly show diet to be the main driver. Dr. Sangwan says the main metabolites associated with early-onset colorectal cancer risk are already known, allowing future research to focus more accurately in this direction.

The researchers suggest that measuring blood metabolites may be easier for identifying at-risk patients than sequencing bacterial DNA in stool to characterize gut microbes. “Changing your microbiome can actually be very complex and difficult. Although not always easy, changing your diet is much simpler for preventing colorectal cancer,” the researcher adds.

Younger patients with early-onset colorectal cancer had higher levels of metabolites associated with production and metabolism of the amino acid arginine and with the urea cycle than older patients. These differences may be associated with long-term red and processed meat consumption.

Commentary

The researchers emphasize that one of the most effective colorectal cancer prevention strategies for people under 60 is to discuss their diets in detail with their physicians.

US national datasets are now being analyzed to test these findings in patients. The researchers expect higher arginine and urea-cycle metabolite levels among younger colorectal cancer patients, linked to excessive red and processed meat consumption. They plan to assess whether specific diets or existing drugs regulating arginine production and the urea cycle could prevent or treat early-onset colorectal cancer.

Although further research is needed to understand how dietary factors trigger colorectal cancer, these findings could inspire important changes in patient care. Lead author Dr. Suneel Kamath explains, “Before this study, although we knew diet played an important role in colorectal cancer risk, I did not always raise it at my first meeting with patients. There is already so much to discuss, and it can be overwhelming for patients,” he says. “Now I always discuss it with my patients and the healthy friends or family members who accompany them, trying to give them the tools to make informed lifestyle choices,” he adds.