A study of 461,682 Americans found no overall link between eating more ultra-processed foods and developing colorectal cancer, also called bowel cancer. Participants were between 50 and 71 when they joined, and researchers followed them for nearly 19 years. Ultra-processed foods go through extensive industrial processing, but this broad category contains many different kinds of food.
When researchers examined individual groups, the results varied. Eating more whole grain foods and dairy products from ultra-processed sources was associated with lower cancer rates. Meat from these sources was associated with higher rates. The team also analyzed replacing ultra-processed foods with minimally processed alternatives, which undergo fewer changes before sale. Replacing 10% of intake by weight was linked to a 2% lower cancer rate. These findings suggest that a food's nutritional content may be more useful than its processing category alone when considering health effects.
However, the study observed people's diets and health rather than testing whether particular foods caused cancer. Most participants were older white Americans, so the results may not apply equally to other populations. Participants also reported their diets only at the beginning, meaning later changes in eating habits were not captured.
