A federal study that followed more than 461,000 older Americans for nearly two decades found no link between total ultra-processed food intake and colorectal cancer, but it did find that the type of processed food matters.
Researchers led by Erikka Loftfield of the National Cancer Institute published the findings Oct. 15 in the journal PLOS Medicine, according to ScienceDaily.
Who was studied
The team used data from the NIH-AARP Diet and Health Study. It enrolled 461,682 Americans ages 50 to 71 in 1995 and 1996 and asked them detailed questions about what they ate. Researchers then tracked who developed colorectal cancer through 2018, a median of 18.8 years.
The researchers sorted foods by how heavily they were processed, then looked at what was in them.
What they found
Total ultra-processed food intake was not associated with overall colorectal cancer rates. “We did not observe an association between total ultra-processed food (UPF) intake and colorectal cancer incidence,” Loftfield said.
The type of food made a difference. Whole grains, fiber, dairy and calcium that came from ultra-processed products were linked to lower colorectal cancer rates. Meat from ultra-processed sources was linked to higher rates.
The researchers also estimated that replacing 10% of ultra-processed food, by weight, with minimally processed foods was associated with a 2% lower rate of colorectal cancer.
Why it matters at the dinner table
Ultra-processed foods make up more than half of the calories American adults eat, so the question of which ones carry risk is a practical one. The study suggests the label “processed” by itself says less than what is actually in the package.
A few takeaways for shoppers:
- Read the label, not the category. A whole-grain bread or a plain yogurt is not the same food as a hot dog, even though both are factory-made.
- Watch the processed meat. The meat category was the one tied to higher risk in this study.
- Keep the fiber, calcium and whole grains coming. Those nutrients were linked to lower risk even when they came in a box or a carton.
- Swap where it’s easy. Trading some packaged foods for minimally processed ones, such as fresh vegetables, eggs, beans or home-cooked meat, was associated with a small benefit.
The limits
The authors were careful about what the study can and can’t show. Participants were mostly older white Americans, so the results may not carry over to younger or more diverse groups. Diet was measured only once, at the start, and ultra-processed foods became more common during the study period. Because it is an observational study, it shows associations, not cause and effect.
The study was funded by the National Cancer Institute’s own research program, which had no role in its design or analysis.
The bottom line
For anyone who cooks at home and shops carefully, this study backs up common sense. Food doesn’t have to come straight from the garden to be good for you, and a box of whole-grain cereal is not the same as a package of processed deli meat. Pay attention to what’s in the food, go easy on processed meats and keep fiber, whole grains and dairy on the menu.