Ultra-processed foods not tied to colorectal cancer overall

Clinical takeaway: Counsel patients to focus on proven colorectal cancer prevention targets, including higher intake of whole grains, fiber, dairy, and calcium and lower intake of processed meats, rather than avoiding all ultra-processed foods as a single category.

Ultra-processed foods (UPFs) provide more than half of calories consumed by U.S. adults, yet studies linking them to colorectal cancer (CRC) have produced conflicting results. Researchers hypothesized that the mixed findings may reflect major differences among UPF types, with some contributing protective dietary components and others contributing established cancer risk factors.

In this prospective NIH-AARP Diet and Health Study analysis, investigators followed 461,682 cancer-free adults aged 50-71 years for a median of 18.8 years. During follow-up, 10,075 colorectal adenocarcinomas were diagnosed, including 4,787 proximal colon, 2,633 distal colon, and 2,389 rectal cancers.

Overall UPF intake was not associated with CRC incidence. Participants in the highest versus lowest quintile of UPF consumption had essentially the same colorectal cancer risk after adjustment for demographic, lifestyle, and health factors. The null findings were also consistent across tumor subsites and after additional adjustment for diet quality and BMI.

However, risk varied substantially by UPF type. Higher intake of UPF sources of whole grains, fiber, dairy, and calcium was associated with lower CRC incidence, while higher intake of UPF meat products was associated with increased incidence. Compared with the lowest intake groups, participants with the highest consumption of breakfast cereals, breads, and dairy-based UPFs experienced roughly 9% to 18% lower CRC incidence, whereas those consuming the most reconstituted meat and fish products had about a 10% higher incidence.

The findings mirrored established dietary guidance. Each additional daily serving of dairy from UPF sources was associated with about a 25% lower CRC incidence, while each daily serving of meat from UPF sources was associated with an 8% higher incidence. Replacing 10% of UPF intake with minimally processed foods was associated with a modest 2% reduction in CRC incidence.

“In this large population of older US adults, we did not observe an association between total ultra-processed food intake and colorectal cancer incidence; however, when we looked at food groups... associations were in line with current dietary guidance for colorectal cancer prevention,” said senior author Erikka Loftfield.

Source: Abar L, et al. (2026 Oct 15) PLoS Med. Associations of food processing and dietary risk factors with colorectal cancer incidence in the NIH-AARP Diet and Health Study: A cohort study