Massive study of 460,000 people challenges ultra-processed food cancer fears
A massive study of more than 460,000 Americans found that ultra-processed foods were not associated with increased colorectal cancer risk overall, challenging a widely held assumption. While processed meat was linked to higher cancer incidence, ultra-processed whole grains and dairy products were associated with lower incidence.
Key points
- A study of 461,682 Americans found no overall link between total ultra-processed food intake and colorectal cancer.
- Whole grain, fiber, dairy and calcium from ultra-processed sources were linked to lower cancer rates; ultra-processed meat to higher rates.
- Replacing 10% of ultra-processed food by weight with minimally processed food was tied to a 2% lower incidence.
A study of more than 460,000 Americans found no overall association between eating ultra-processed food and colorectal cancer incidence, according to findings led by Erikka Loftfield of the National Cancer Institute and published October 15 in PLOS Medicine. The research tracked 461,682 people aged 50 to 71 who joined the NIH-AARP Diet and Health Study in 1995 and 1996, following them through 2018 with a median follow-up of 18.8 years.
While total ultra-processed food intake showed no link to cancer rates, the results differed by food type. Some ultra-processed foods were associated with lower cancer rates and others with higher rates, suggesting the health effects may depend on what the foods contain.
How food types differed
Higher consumption of whole grains, fiber, dairy products and calcium from ultra-processed sources was associated with a lower incidence of colorectal cancer. Meat from ultra-processed sources showed the opposite pattern, with greater consumption linked to higher cancer incidence.
The team also found that substituting minimally processed foods for 10% of ultra-processed food intake by weight was associated with a 2% lower incidence of colorectal cancer.
we did not observe an association between total ultra-processed food (UPF) intake and colorectal cancer incidence
— Erikka Loftfield
Limits of the study
The researchers caution the findings may not apply equally to everyone, since most participants were older, white Americans. Dietary information was collected only once, at the start of the study, so later changes in diet could not be accounted for, and the variety of ultra-processed foods grew during the follow-up period.
Because the research was observational, it cannot establish whether particular foods directly increase or decrease cancer risk. The authors said the results align with current dietary guidance for colorectal cancer prevention.
