Large US cohort finds no link between total ultra-processed food intake and colorectal cancer in older adults

A study published in PLOS Medicine on 15 October 2026 found that total ultra-processed food (UPF) intake was not associated with colorectal cancer in a large cohort of older US adults.

Study type and methods

This is an observational cohort study using the NIH-AARP Diet and Health Study. It included 461,682 adults aged 50 to 71 who were cancer-free when they enrolled in 1995–96 and reported their diet through a food-frequency questionnaire. Foods were classified by the Nova processing system. Participants were followed through 2018, during which 10,075 colorectal adenocarcinoma cases were diagnosed. Median UPF intake was about 43% of daily energy.

Main findings

• Comparing the highest with the lowest fifth of UPF intake, the hazard ratio was 0.97 (95% CI 0.91–1.03) — no clear difference in risk.
• Within UPFs, foods that supplied whole grains, fibre, dairy and calcium were linked to lower risk (breakfast cereals, for example, had a hazard ratio of 0.84), while meat from UPF sources was linked to higher risk.
• The authors suggest these opposing effects may partly explain the overall null result, and say the findings support existing advice to eat whole grains, fibre, dairy and calcium and to avoid processed meat.

As NBC News noted, the results do not explain rising colorectal cancer rates among younger people, which the study did not examine.

Limitations

The authors cite residual confounding and misclassification from self-reported diet; diet was measured mainly at baseline decades ago; the cohort covers only older US adults. An observational design cannot prove cause and effect. This is not personal medical advice — talk to your doctor about diet and screening.