10/17/2026
**A food can provide beneficial nutrients and still contain carcinogenic compounds.** That is my central objection to interpreting this study as reassurance about ultra-processed foods: an association between fiber or calcium intake and lower colorectal cancer incidence does not establish that processing-related chemicals are harmless. Some processing methods, including curing and smoking, can generate carcinogenic compounds such as certain N-nitroso compounds and polycyclic aromatic hydrocarbons, regardless of whether beneficial nutrients remain present (International Agency for Research on Cancer, 2018). The study’s authors acknowledge that they lacked ingredient-level information to evaluate food additives. Their nutrient findings therefore cannot answer the chemical-safety question (Abar et al., 2026).
**The exposure measurement creates another substantial limitation.**
This analysis relied on a single dietary questionnaire completed in 1995–1996,
with cancer diagnoses tracked through 2018. That snapshot cannot establish what participants ate throughout the following decades, how product formulations changed, or their cumulative exposure to specific chemicals. A large sample cannot recover exposure information that was never collected. The overall ultra-processed food category also combines very different products; the study’s own subgroup analysis associated greater intake of reconstituted meat and fish products with higher colorectal cancer incidence. Historical diet can inform cancer research, but using this study’s overall result to reassure the public that ultra-processed foods do not contribute to cancer goes beyond what its measurements can establish (Abar et al., 2026).
**References**
Abar, L., O’Connell, C. P., Hong, H. G., Herrick, K. A., Kahle, L., Lerman, J. L., Liao, L. M., Zhang, X., Zhang, X., Zhao, L., Zouiouich, S., Sinha, R., Khandpur, N., Martínez Steele, E., & Loftfield, E. (2026). Associations of food processing and dietary risk factors with colorectal cancer incidence in the NIH-AARP Diet and Health Study: A cohort study. *PLOS Medicine, 23*(10), Article e1005251. doi:10.1371/journal.pmed.1005251
International Agency for Research on Cancer. (2018). *Red meat and processed meat* (IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 114).
In this study, Leila Abar and colleagues examine ultra-processed food intake and colorectal cancer incidence in a large prospective cohort, finding no overall association and suggesting that the nutritional composition of these foods may be more relevant than their level of processing alone.
