Ultra-Processed Food Cancer Study of 460,000

A new analysis of more than 460,000 adults gives shoppers a clearer way to read the grocery aisle: for ultra-processed food and cancer risk, what a food actually contains appears to matter more than its processing label. Researchers reported that higher total ultra-processed food intake was not associated with a higher overall incidence of colorectal cancer, though individual food groups pointed in opposite directions. The study, led by Erikka Loftfield of the National Cancer Institute, was published October 15 in the open-access journal PLOS Medicine.

What did the study find?

According to the researchers, participants who ate more ultra-processed food did not, as a group, develop colorectal cancer at higher rates. The headline result was the absence of an overall association between total ultra-processed food consumption and colorectal cancer incidence.

A closer look at specific food categories told a more detailed story. The researchers reported that 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 associated with higher cancer incidence. Ultra-processed foods account for more than half of the calories consumed by American adults, and the category spans a wide range of products, which the authors say makes it hard to judge as a single group.

How was the research conducted?

The team examined health and dietary records from 461,682 Americans who were between 50 and 71 years old when they joined the NIH-AARP Diet and Health Study in 1995 and 1996. Participants completed questionnaires describing how often they ate different foods, and researchers used those responses to estimate each person’s ultra-processed food intake. Participants were tracked through 2018, with a median follow-up of 18.8 years, covering nearly two decades of cancer outcomes.

Does swapping foods change the picture?

The researchers also modeled what might happen when ultra-processed foods were replaced with less processed options. Their analysis 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. The authors say this supports judging foods by their nutritional content and specific health associations rather than treating everything labeled ultra-processed as equally harmful.

In a statement accompanying the study, Loftfield said: “In this large population of older US adults, we did not observe an association between total ultra-processed food (UPF) intake and colorectal cancer incidence; however, when we looked at food groups, like whole grains, dairy, and meat, by UPF or non-UPF source, we found that associations were in line with current dietary guidance for colorectal cancer prevention such that higher whole grain and dairy but lower meat intakes were associated with lower colorectal cancer incidence.”

Why do the findings come with limits?

The authors are careful about how far the results reach. Most participants were older, white Americans, so the findings may not reflect the experience of younger adults or more racially and ethnically diverse groups. Participants reported their eating habits only once, at the start of the study, so the researchers could not account for diet changes over the following decades. The availability and variety of ultra-processed foods also grew over that period, which the authors say may mean the baseline questionnaires underestimated actual consumption. Because the study was observational, it cannot establish whether particular foods directly raise or lower cancer risk.

What to do now

The study and current dietary guidance it cites describe these steps.

Read foods by their contents, not just a processing label. The same broad category held items linked to both lower and higher cancer incidence.
Favor whole grains, fiber, dairy, and calcium-rich foods, which were associated with lower colorectal cancer incidence in this study and align with existing prevention guidance.
Limit processed meat, the ultra-processed source linked to higher cancer incidence here.
Where it is easy, replace some ultra-processed items with minimally processed alternatives. The study linked swapping 10% of intake by weight with a 2% lower incidence.
Treat the results as population averages, not personal predictions, since the research was observational and drawn mostly from older adults.

FAQ

Does ultra-processed food cause colorectal cancer?

The study did not find an association between total ultra-processed food intake and overall colorectal cancer incidence, and because it was observational it cannot establish that any food directly causes or prevents cancer.

Which ultra-processed foods were linked to lower cancer risk?

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 was associated with a higher incidence.

How large was the study and how long did it run?

Researchers studied 461,682 Americans aged 50 to 71 at enrollment in 1995 and 1996, tracking them through 2018 with a median follow-up of 18.8 years.

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