Recent studies show a concerning rise in colorectal cancer diagnoses among adults aged 50 and younger, particularly in high-income nations such as the United States. The precise causes of this upward trend remain unclear; however, a new investigation led by researchers from Harvard and Mass General Brigham may have uncovered a significant connection between this rise and the consumption of ultraprocessed foods.
The research team analyzed dietary habits and endoscopy results from nearly 30,000 women, revealing a striking correlation. Participants who had the highest intake of ultraprocessed foods were found to have a 45 percent increased risk of developing adenomas, which can serve as precursors to early-onset colorectal cancer, in comparison to those with the lowest consumption rates. The findings, which highlight an urgent need for dietary adjustments, were published in JAMA Oncology.
Senior author Andrew Chan, a gastroenterologist affiliated with the Mass General Brigham Cancer Institute and a professor at Harvard Medical School, emphasized the gravity of these findings. “Our results support the significance of decreasing ultraprocessed food consumption as a potential measure to alleviate the increasing incidence of early-onset colorectal cancer,” he stated. Chan noted that the relationship between ultraprocessed food consumption and cancer risk appears to be linear—indicating that higher food intake correlates with a greater likelihood of developing colon polyps.
Ultraprocessed foods are defined as ready-to-eat products that typically consist of excessive amounts of sugar, salt, saturated fat, and various food additives. In recent years, the consumption of these foods has surged alongside a notable increase in early-onset colorectal cancer cases. Chan’s research group had earlier established a broader link between ultraprocessed foods and colorectal cancer, but this study specifically illuminates their potential role in early-onset cases.
The research utilized data from the Nurses’ Health Study II, a long-term analysis involving female nurses born between 1947 and 1964—a demographic identified as being particularly at risk for early colorectal cancer. The study analyzed 24 years of information from 29,105 participants who underwent multiple lower endoscopies for cancer screening, while also completing dietary assessments every four years. This self-reported dietary data has been validated for its accuracy.
Participants reported an average of 5.7 servings of ultraprocessed foods daily, which constituted 35 percent of their total caloric intake—a figure that is slightly below the national average in the U.S. Out of the endoscopic evaluations, 2,787 participants were diagnosed with precursor polyps for colorectal cancer. Women consuming the most ultraprocessed foods—about 10 servings per day—exhibited a 45 percent heightened risk of developing conventional adenomas compared to those averaging three servings daily. Interestingly, no correlation was observed between ultraprocessed food intake and serrated lesions, which are associated with slower development and are less commonly linked to early-onset colorectal cancer.
One key advantage of this study was the detailed consideration of various colorectal cancer risk factors among participants, including body mass index, Type 2 diabetes, and dietary fiber intake. Despite accounting for these additional risks, the link between ultraprocessed foods and adenoma development remained robust.
Chan also underscored the fact that ultraprocessed foods do not fully account for the increasing rates of early-onset colorectal cancer. The team is actively exploring additional risk factors for this illness while striving to enhance the categorization of ultraprocessed foods, as distinctions between them may reveal varied health impacts.
“Diet is not the sole explanation for this phenomenon; we encounter numerous patients with early-onset colorectal cancer who follow healthy dietary patterns,” Chan remarked. Addressing other potential risk factors is part of the ongoing research at the Mass General Brigham Cancer Institute. This essential study, backed by funding from the National Cancer Institute, aims to deepen the understanding of early-onset colorectal cancer and uncover actionable interventions.