Opinion: The Western Diet May Contribute to Young-Onset Colorectal Cancer

Amanda Brink, DNP, APRN, FNP-BC, AOCNP

In recent years, the landscape of colorectal cancer (CRC) has undergone a notable shift. Once predominantly considered a disease affecting older adults, there has been a concerning rise in the incidence of colorectal cancer among younger patients.¹ The onset of colorectal cancer in individuals under the age of 50 is classified as early-onset CRC. While genetic predispositions certainly play a significant role, with approximately 20% of early-onset CRC attributed to germline mutations,² emerging research suggests that environmental factors, particularly dietary habits, may be contributing to this alarming trend and the development of sporadic early-onset CRC.

Among these dietary factors, the Western diet—a pattern characterized by high intake of red and processed meats, refined grains, sugary beverages, and low consumption of fruits, vegetables, and fiber—has garnered considerable attention.³

In this article, we will examine some of the latest research on environmental factors, with a focus on the impact of the Western diet, in the development of early-onset CRC.

Western Diet and Its Role in Rising Young-Onset Colorectal Cancer Rates

Researchers from Ohio State University presented a poster at the 2024 American Society of Clinical Oncology Annual Meeting describing how the Western diet may contribute to the increase of early-onset CRC by causing an imbalance in the intestinal microbiome.⁴

The authors explained that the intestinal microbiome, referring to the diverse community of microorganisms residing in the gastrointestinal tract that play essential roles in digestion, nutrient metabolism, and immune system regulation,⁵ breaks down dietary fibers into microbial metabolites crucial for intestinal health, including maintaining the integrity of the intestinal epithelium. However, a diet high in fat and low in fiber can upset this balance, a phenomenon known as intestinal dysbiosis, leading to inflammation. This inflammation could create an environment in the intestines that supports tumor growth and hinders the body's ability to fight cancer by suppressing antitumor immune surveillance. The authors also explained that diet can also impact epigenetic alterations—changes in gene expression caused by modifications to DNA or associated proteins—in the colon, which may play a role in the development of sporadic early-onset CRC.

The authors collected RNA sequencing data from the Cancer Genome Atlas and the Oncology Research Information Exchange Network, both of which collect and share extensive genetic data. They used this data to analyze the microorganisms present within the tumors of patients with early-onset CRC. They also examined the presence and characteristics of immune cells that have penetrated the tumors, known as tumor-infiltrating lymphocytes, a type of immune cell which can influence cancer progression and response to treatment.⁶ They aimed to identify different biological pathways that are active in early-onset CRC, which could reveal how the cancer develops and progresses. Additionally, they utilized tools to analyze DNA methylation, a type of chemical modification that affects gene expression,⁷ to identify regions of the DNA that were differently methylated in early-onset CRC tumors compared to other samples.

The authors found that the presence of Fusobacterium bacteria might contribute to inflammation, a characteristic feature of early-onset CRC. They also found that, within tumors of patients with early-onset CRC, the presence of certain microbes is associated with an increase in M2 macrophages, a type of immune cell that can promote tumor growth and suppress the immune response.⁸ Compared to patients with late-onset CRC, those with early-onset CRC show distinct patterns of gene activity related to processes like phagosome formation (a mechanism for engulfing and breaking down foreign particles),⁹ signaling pathways of proteins which are involved in various cellular processes, and cAMP-responsive element binding (CREB) protein signaling in neurons, which regulates gene expression in nerve cells.¹⁰

Epigenetic clocks are a way to estimate biological age based on DNA methylation.¹¹ In patients with early-onset CRC, these clocks indicated that the cells in their tumors appear to be biologically older than expected based on their chronological age, whereas methylation ages in patients with late-onset CRC were comparable with chronological ages.

These data suggest that harmful microbes may trigger inflammation, which contributes to accelerated aging in early-onset CRC.

Nursing Considerations

As CRC incidence among younger adults continues to rise, understanding the environmental and dietary factors contributing to this trend becomes increasingly critical. Nurses play a pivotal role in translating these scientific insights into actionable advice for patients. By educating patients on the importance of a balanced diet rich in fiber and low in processed foods and unhealthy fats, nurses can help mitigate the risk of developing early-onset CRC. Understanding the impact of diet on gut health and its broader implications for cancer development allows nurses to guide patients in making informed dietary choices. This proactive approach not only empowers patients to take control of their health but also underscores the critical role of lifestyle modifications in cancer prevention.

References

1. Spaander MCW, Zauber AG, Syngal S, et al. Young-onset colorectal cancer. Nat Rev Dis Primers. 2023;9(1):21. Published 2023 Apr 27. doi:10.1038/s41572-023-00432-7
2. Zhang S, Xu R, Hu M, et al. Distinct plasma molecular profiles between early-onset and late-onset colorectal cancer patients revealed by metabolic and lipidomic analyses. J Pharm Biomed Anal. 2024;241:115978. doi:10.1016/j.jpba.2024.115978
3. Clemente-Suárez VJ, Beltrán-Velasco AI, Redondo-Flórez L, Martín-Rodríguez A, Tornero-Aguilera JF. Global Impacts of Western Diet and Its Effects on Metabolism and Health: A Narrative Review. Nutrients. 2023;15(12):2749. Published 2023 Jun 14. doi:10.3390/nu15122749
4. Jin N, Hoyd R, Yilmaz AS, et al. Microbiome signature, immune landscape and global methylation in early onset colorectal cancer. J Clin Oncol. 2024;42(16). Published 2024 May 29. doi:10.1200/JCO.2024.42.16_suppl.3580
5. The Microbiome. Harvard T.H. Chan School of Public Health. Accessed June 14, 2024. https://nutritionsource.hsph.harvard.edu/microbiome/
6. Tumor-Infiltrating Lymphocyte. National Cancer Institute. Accessed June 14, 2024. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/tumor-infiltrating-lymphocyte
7. Moore LD, Le T, Fan G. DNA methylation and its basic function. Neuropsychopharmacology. 2013;38(1):23-38. doi:10.1038/npp.2012.112
8. Boutilier AJ, Elsawa SF. Macrophage Polarization States in the Tumor Microenvironment. Int J Mol Sci. 2021;22(13):6995. Published 2021 Jun 29. doi:10.3390/ijms22136995
9. Jaumouillé V, Grinstein S. Molecular Mechanisms of Phagosome Formation. Microbiol Spectr. 2016;4(3):10.1128/microbiolspec.MCHD-0013-2015. doi:10.1128/microbiolspec.MCHD-0013-2015
10. Sakamoto K, Karelina K, Obrietan K. CREB: a multifaceted regulator of neuronal plasticity and protection. J Neurochem. 2011;116(1):1-9. doi:10.1111/j.1471-4159.2010.07080.x
11. Duan R, Fu Q, Sun Y, Li Q. Epigenetic clock: A promising biomarker and practical tool in aging. Ageing Res Rev. 2022;81:101743. doi:10.1016/j.arr.2022.101743